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How your gut influences your mood and behaviour Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link The dopamine connection 11/07/25, 10:02 Last updated: Published: 25/03/24, 12:01 How your gut influences your mood and behaviour Introduction to dopamine Dopamine is a neurotransmitter derived from an amino acid called phenylalanine, which must be obtained through the diet, through foods such as fish, meat, dairy and more. Dopamine is produced and released by dopaminergic neurons in the central nervous system and can be found in different brain regions. The neurotransmitter acts via two mechanisms: wiring transmission and volume transmission. In wiring transmission, dopamine is released to the synaptic cleft and acts on postsynaptic dopamine receptors. In volume transmission, extracellular dopamine arrives at neurons other than postsynaptic ones. Through methods such as diffusion, dopamine then reaches receptors in other neurons that are not in direct contact with the cell that has released the neurotransmitter. In both mechanisms, dopamine binds to the receptors, transmitting signals between neurons and affecting mood and behaviour. The link between dopamine and gut health Dopamine has been known to result in positive emotions, including pleasure, satisfaction and motivation, which can be influenced by gut health. Therefore, what you eat and other factors, including motivation, could impact your mood and behaviour. This was proven by a study (Hamamah et al., 2022), which looked at the bidirectional gut-brain connection. The study found that gut microbiota was important in maintaining the concentrations of dopamine via the gut-brain connection, also known as the gut microbiota-brain axis or vagal gut-to-brain axis. This is the communication pathway between the gut microbiota and the brain facilitated by the vagus nerve, and it is important in the neuronal reward pathway, which regulates motivational and emotional states. Activating the vagal gut-to-brain axis, which leads to dopamine release, suggests that modulating dopamine levels could be a potential treatment approach for dopamine-related disorders. Some examples of gut microbiota include Prevotella, Bacteroides, Lactobacillus, Bifidobacterium, Clostridium, Enterococcus, and Ruminococcus , and they can affect dopamine by modulating dopaminergic activity. These gut microbiota are able to produce neurotransmitters, including dopamine, and their functions and bioavailability in the central nervous system and periphery are influenced by the gut-brain axis. Gut dysbiosis is the disturbance of the healthy intestinal flora, and it can lead to dopamine-related disorders, including Parkinson's disease, ADHD, depression, anxiety, and autism. Gut microbes that produce butyrate, a short-chain fatty acid, positively impact dopamine and contribute to reducing symptoms and effects seen in neurodegenerative disorders. Dopamine as a treatment It is important to understand the link between dopamine and gut health, as this could provide information about new therapeutic targets and improve current methods that have been used to prevent and restore deficiencies in dopamine function in different disorders. Most cells in the immune system contain dopamine receptors, allowing processes such as antigen presentation, T-cell activation, and inflammation to be regulated. Further research into this could open up a new possibility for dopamine to be used as a medication to treat diseases by changing the activity of dopamine receptors. Therefore, dopamine is important in various physiological processes, both in the central nervous and immune systems. For example, studies have shown that schizophrenia can be treated with antipsychotic medications which target dopamine neurotransmission. In addition, schizophrenia has also been treated by targeting the dysregulation (decreasing the amount) of dopamine transmission. Studies have shown promising results regarding dopamine being used as a form of treatment. Nevertheless, further research is needed to understand the interactions between dopamine, motivation and gut health and explore how this knowledge can be used to create medications to treat conditions. Conclusion The bidirectional gut-brain connection shows the importance of gut microbiota in controlling dopamine levels. This connection influences mood and behaviour but also has the potential to lead to new and innovative dopamine-targeted treatments being developed (for conditions including dopamine-related disorders). For example, scientists could target and manipulate dopamine receptors in the immune system to regulate the above mentioned processes: antigen presentation, T-cell activation, and inflammation. While current research has shown some promising results, further investigations are needed to better comprehend the connection between gut health and dopamine levels. Nevertheless, through consistent studies, scientists can gain a deeper understanding of this mechanism to see how changes in gut microbiota could affect dopamine regulation and influence mood and behaviour. Written by Naoshin Haque Related articles: the gut microbiome / Crohn's disease / Microbes in charge Project Gallery

Exenatide as a potential drug Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link A common diabetes drug treating Parkinson’s disease 08/07/25, 14:37 Last updated: Published: 24/01/24, 21:15 Exenatide as a potential drug A new investigational drug, originally developed for type 2 diabetes, is being readied for human clinical trials in search of the world's first treatment to impede Parkinson's disease progression. Parkinson's (PD) is the second most common neurodegenerative disorder. The connection between type 2 diabetes (T2DM) and PD was discovered in 1993, when PD patients with co-existing T2DM had worse motor symptoms and response to therapy. Dopaminergic neurons promote eating behaviour in hypoglycaemic states, mediated via insulin receptors in the substantia nigra, because dopaminergic neuronal loss affects glycaemic control. Thus, T2DM patients are more likely to acquire PD than people without diabetes. Excess glucose in the brain, as found in uncontrolled T2DM, may interact randomly with surrounding proteins and interfere with their function. These interactions also result in toxic end products promoting inflammation and α-synuclein clustering, both of which are PD characteristics. Over a 12-year period, retrospective data (N=8,190,323) showed that T2DM responders had considerably greater PD rates when compared to those without diabetes. The rise was significantly more pronounced among individuals with complex T2DM and those aged 25-44. Exenatide: Overview and Mechanism of Action Exenatide is a synthetic form of exendin-4, a naturally occurring protein identified in the saliva of the Gila monster (poisonous lizard endemic to the Southwest US) by Dr. Eng in the early 1990s. In humans, the chemical is produced after a meal to increase insulin production, decreasing blood sugar. GLP-1 degrades fast in humans, and its benefits are short-lived. However, investigations have shown effects of exendin-4 continue longer in people. This finally led to FDA clearance in 2005, when the product was sold as Byetta TM . Its current indications are for the treatment of balancing glucose levels in T2DM with or without additional oral hypoglycemic medications. This glycaemic control is an analogue of human GLP-1, used in T2DM treatment, either alone or in conjunction with other antidiabetic medications. Exendin-4's neuroprotective characteristics may aid in rescuing degenerating cells and neuron protection. Because T2DM and PD are linked, researchers want to explore its effectiveness as a PD therapy. Patients treated with exenatide for one year (in addition to standard medication) experienced less deterioration in motor symptoms when tested without medication compared to the control group. Research on Exenatide as a Potential Parkinson's Disease Therapy 21 patients with intermediate PD were assessed over a 14-month period, and their progress was compared to 24 other people with Parkinson's who served as controls. Exenatide was well accepted by participants, albeit some individuals complained about weight loss. Significantly, exenatide-treated participants improved their PD movement symptoms, while the control patients continued to deteriorate. The researchers investigate exenatide, a possible PD therapy, in an upcoming clinical study, lending support to the repurposing of diabetes drugs for Parkinson's patients. This research adds to the evidence for a phase 3 clinical trial of exenatide for PD patients. Data on 100,288 T2DM revealed that people using two types of diabetic medications, GLP-1 agonists and DPP4-inhibitors, were less likely to be diagnosed with Parkinson's up to 3.3 years follow-up. Those who used GLP-1 agonists were 60% less likely to acquire PD than those who did not. The results revealed that T2DM had a higher risk of Parkinson's than those without diabetes, although routinely given medicines, GLP-1 agonists, and DPP4-inhibitors seemed to reverse the association. Furthermore, a 2-year follow-up research indicated individuals previously exposed to exenatide displayed a substantial improvement in their motor characteristics 12 months after they ceased taking the medication. However, this experiment was an open-label research so the gains may be explained by a placebo effect. The research adds to the evidence that exenatide may assist to prevent or treat PD, perhaps by altering the course of the illness rather than just lowering symptoms. Other risk factors for PD should be considered by clinicians when prescribing T2DM drugs, although further study is required to clarify clinical significance. Findings from Clinical Trials and Studies Based on these findings, the UCL team broadened their investigation and conducted a more extensive, double-blind, placebo-controlled experiment. The findings establish the groundwork for a new generation of PD medicines, but they also confirm the repurposing of a commercially existing therapy for this illness. Patients were randomly randomised (1:1) to receive exenatide 2 mg or placebo subcutaneous injections once weekly in addition to their current medication for 48 weeks, followed by a 12-week washout period. Web-based randomisation was used, with a two-stratum block design depending on illness severity. Treatment allocation was concealed from both patients and investigators. The main outcome was the adjusted difference in the motor subscale of the Movement Disorders Society Unified Parkinson's Disease Rating Scale after 60 weeks in the realistically defined off-medication condition. Six major adverse events occurred in the exenatide group and two in the placebo group, but none were deemed to be connected to the research treatments in either group. It is unclear if exenatide alters the underlying illness mechanism or causes long-term clinical consequences. Implications and Future Directions Indeed, the UCL study showed that exenatide decreases deterioration compared to a placebo. However, participants reported no change in their quality of life. The study team would broaden their study to include a broader sample of people from several locations. Because PD proceeds slowly, longer-term trials might provide a better understanding of how exenatide works in these responders. Overall, findings suggest that gathering data on this class of medications should be the topic of additional inquiry to evaluate their potential. Exenatide is also being studied to see whether it might postpone the onset of levodopa-induced problems (e.g., dyskinesias). Furthermore, if exenatide works for Parkinson's, why not for other neurodegenerative illnesses (Alzheimer's, amyotrophic lateral sclerosis, Huntington's disease, multiple sclerosis) or neurological diseases (including cerebrovascular disorders, traumatic brain injury...)? Exenatide has been FDA-approved for diabetes for many years and has a good track record, but it does have some adverse side effects in Parkinson's patients, namely gastrointestinal difficulties (nausea, constipation). Exenatide as a prospective PD therapy is an example of medication repurposing or repositioning, an essential method for bringing novel therapies to patients in a timely and cost-effectively. However, further research is required, so it will be many years before a new therapy is licenced and available. Drug repurposing, or using authorised medicines for one ailment to treat another, opens up new paths for Parkinson's therapeutic development. Conclusion Exenatide shows potential as a therapy for Parkinson's disease (PD). Studies have shown that exenatide may help improve motor symptoms and slow down the progression of PD. However, further research and clinical trials are needed to fully understand its effectiveness and long-term effects. The findings also suggest that repurposing existing medications, like exenatide, could provide new avenues for developing PD therapies. While exenatide shows promise, it will likely be many years before it is licensed and widely available as a PD treatment. PROJECT GALLERY IMAGES DESCRIPTION Figure 1- The use of GLP-1 is beyond diabetes treatment. Nineteen clinical studies found that GLP-1 agonists can improve motor scores in Parkinson's Disease, improve glucose metabolism in Alzheimer's, and improve quality of. They can also treat chemical dependency, improve lipotoxicity, and reduce insulin resistance. However, adverse effects are primarily gastrointestinal. Thus, GLP-1 analogues may be beneficial for other conditions beyond diabetes and obesity. Figure 2- Potent GLP-1 agonists suppress appetite through a variety of mechanisms, including delayed gastric emptying, increased glucose-dependent insulin secretion, decreased glucagon levels, and decreased food ingestion via central nervous system effects. Short-acting agents, including exenatide, primarily function by impeding gastric evacuation, thereby leading to a decrease in postprandial glucose levels. On the contrary, extended-release exenatide and other long-acting agonists (e.g., albiglutide, dulaglutide) exert a more pronounced impact on fasting glucose levels reduction via their mechanism of action involving the release of insulin and glucagon. The ineffectiveness of long-acting GLP-1 receptor agonists on gastric evacuation can be attributed to the development of tolerance to GLP-1 effects, which is regulated by parasympathetic tone alterations. Figure 3- Illustrated is the cross-communication with insulin receptor signalling pathways and downstream effectors . Biomarkers can be derived from the formation and origin of extracellular vesicles, which indicate the initial inward budding of the plasma membrane. An early endosome is formed when this membrane fuses; it subsequently accumulates cytoplasmic molecules. As a consequence, multivesicular bodies are generated, which subsequently fuse with the plasma membrane and discharge their constituents into the extracellular milieu. Akt denotes protein kinase B; Bcl-2 signifies extracellular signal-related kinase; Bcl-2 antagonist of death; Bcl-2 extra large; Bcl-XL signifies Bcl-2; Bim signifies Bcl-2-like protein 11; cAMP signifies cyclic adenosine monophosphate; CREB signifies cAMP response element-binding protein; Erk1/2 signifies extracellular signal-related kinase IDE, insulin-degrading enzyme; IL-1α, interleukin 1α; IRS-1, insulin receptor signalling substrate 1; MAPK, mitogen-associated protein kinase; mTOR, mechanistic target of rapamycin; mTORC1, mTOR complex 1; mTORC2, mTOR complex 2; NF-kB, nuclear factor–κB; PI3-K, phosphoinositide 3-kinase; PKA, protein kinase; FoxO1/O3, forkhead box O1/O3, forkhead box O1/O3; GRB2, growth factor receptor-bound protein 2; GSK-3β, Written by Sara Maria Majernikova Related articles: Pre-diabetes / Will diabetes mellitus become an epidemic? / Parkinson's risk / Markers for Parkinsonism Project Gallery

Bilingual individuals must regularly manage interference, focus their attention, and switch between linguistic rules Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link Does being bilingual make you smarter? Last updated: 06/12/25, 20:07 Published: 11/12/25, 08:00 Bilingual individuals must regularly manage interference, focus their attention, and switch between linguistic rules The question of whether bilingualism makes a person smarter has fascinated researchers for years, and modern neuroscience provides strong evidence that speaking multiple languages gives the brain a significant cognitive workout. Because both language systems are constantly active, bilingual individuals must regularly manage interference, focus their attention, and switch between linguistic rules. This continuous practice strengthens executive functions, the mental skills responsible for problem solving, inhibition, and flexible thinking, resulting in sharper overall cognitive control. Brain imaging research highlights these effects clearly. When bilinguals switch between languages, areas such as the dorsolateral prefrontal cortex and the anterior cingulate cortex show increased activation, the same regions involved in handling complex decisions and monitoring conflicting information ( Figure 1 ). The left inferior frontal gyrus, a core language production area, also contributes to nonverbal cognitive control. This overlap suggests that the very skills required to manage multiple languages spill over into broader mental abilities, making the bilingual brain more efficient at processing information far beyond the realm of language. Together, these neural advantages align with emerging evidence that the sustained cognitive engagement required to manage multiple languages may offer long-term neuroprotective effects, including a meaningful delay in the onset of dementia. The cognitive boost extends into sensory processing as well. Studies show that bilingual adolescents encode speech sounds more robustly, especially in noisy environments. Their stronger brainstem responses reveal enhanced auditory attention and sharper sound discrimination ( Figure 2 ). This means that the mental discipline of navigating multiple languages does not only affect high level reasoning but also improves the brain’s ability to detect, filter, and interpret sound, giving bilingual individuals an advantage in environments where listening is challenging. These advantages are reinforced by physical changes within the brain itself. Learning and using multiple languages increases grey matter density and strengthens white matter pathways involved in communication between brain regions. Even a few months of second language learning can produce measurable structural changes. Taken together, these neurological, cognitive, and sensory benefits demonstrate that knowing multiple languages profoundly shapes the brain. While bilingualism may not raise IQ scores in the strictest sense, it enhances mental flexibility, attention, memory, and auditory precision, suggesting that in many practical ways, being bilingual truly does make you smarter. Written by Maria Z Kahloon Related articles: The mutualism theory of general intelligence / Childhood intelligence Project Gallery

CRISPR, regenerative medicine, vaccine development and recombinant DNA tech Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link Medical Biotechnology 10/07/25, 10:21 Last updated: Published: 03/06/23, 13:57 CRISPR, regenerative medicine, vaccine development and recombinant DNA tech Introduction Throughout the course of human history, the foundation of medicine has predominantly relied upon biochemistry. Whereby, scientists utilise naturally occurring and artificially synthesised chemical compounds to elicit therapeutic responses within the body. However, during the 21st century, the field of medicine witnessed a paradigm shift towards medical biotechnology- driving major breakthroughs in healthcare. What is medical biotechnology? Medical biotechnology can be defined as the use of living organisms or their products to investigate, understand and target biological systems in order to improve healthcare outcomes. By integrating the principles of genetic engineering and biological processes, scientists are able to develop novel pharmaceuticals and create diagnostic tools for disease management. Major advancements in medical biotechnology A groundbreaking technology within this field is the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) — Cas9 system. Which utilises CRISPR-associated protein Cas9 and guide RNA (gRNA) as a molecular tool to precisely modify genetic material. By harnessing this gene editing system, scientists can manipulate specific DNA sequences and modulate gene expression, making it an invaluable tool towards precision medicine. Its ability to correct genetic defects has shown promise in the future development of targeted therapies for genetic diseases. Regenerative medicine, another frontier in medical biotechnology aims to regenerate damaged or diseased tissues and organs. This interdisciplinary field integrates principles from tissue engineering and stem cell biology to enable tissue repair and regeneration. Stem cells possess a remarkable capacity to self-renew and differentiate into various specialised cell types. Through research biotechnologists seek to engineer functional tissues and organs for transplantation or stimulate the body's innate regenerative abilities. The development of vaccines is yet another critical aspect of medical biotechnology. Vaccines are designed to stimulate the immune system and confer immunity against specific pathogens, thereby preventing infectious diseases. Modern biotechnology techniques, such as genetic engineering and cell culture, enable cost-effective vaccine development. Recombinant DNA technology enables antigen production in non-pathogenic host cells, eliminating the need for pathogen harvesting. Ongoing advancements include RNA/DNA vaccines, allowing antigen production within recipients' bodies. Conclusion Medical biotechnology continues to play a pivotal role in advancing scientific knowledge and enhancing disease diagnostics and treatment. It holds immense promise for the future of healthcare, particularly in the field of precision medicine. However, it is crucial to acknowledge that this technology also carries inherent risks. Misuse can lead to negative consequences, such as bioterrorism and other destructive outcomes. Written by Komal Nasir Related article: Biggest innovations in the biosciences currently Project Gallery

Looking at p53 mutations and cancer predisposition Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link Decoding p53: the guardian against cancer 09/07/25, 14:03 Last updated: Published: 23/11/23, 11:38 Looking at p53 mutations and cancer predisposition Being a tumour suppressor protein, p53 encoded by the TP53 gene plays a critical role in regulating cell division and preventing the formation of tumours. Its function in maintaining genome stability is vital in inhibiting cancer development. Understanding p53 Located on chromosome locus 17p13.1, TP53 encodes the p53 transcription factor 1. Consisting of three domains, p53 can directly initiate or suppress the expression of 3661 different genes involved in cell cycle control and DNA repair 2. With this control, p53 can influence cell division on a massive scale. Cancer is characterised by uncontrolled cell division, which can occur due to accumulated mutations in either proto-oncogenes or tumour suppressor genes. Wild-type p53 can repair mutations in oncogenes such that they will not affect cell division. However, if p53 itself is mutated, then its ability to repair DNA and control the cell cycle is inhibited, leading to the emergence of cancer. Mutations in TP53 are actually the most prevalent genetic alterations found in patients with cancer. The mechanisms by which mutated p53 leads to cancer are manifold. One such mechanism is p53’s interaction with p21. Encoded by CDKN1A , p21 is activated by p53 and prevents cell cycle progression by inhibiting the activity of cyclin-dependent kinases (CDKs). Therefore, we can see that a non-functional p53 would lead directly to uncontrolled cell division and cancer. Clinical significance The importance of p53 in preventing cancer is highlighted by the fact that individuals with inherited TP53 mutations (a condition known as Li-Fraumeni syndrome or LFS) have a significantly greater risk of developing any cancer. These individuals inherit one defective TP53 allele from one parent, making them highly susceptible to losing the remaining functional TP53 allele, ultimately leading to cancer. Loss of p53 also endows cells with the ability to ignore pro-apoptotic signals such that if a cell becomes cancerous, it is far less likely to undergo programmed cell death 3. Its interactions with the apoptosis-inducing proteins Bax and Bak, are lost when mutated, thus leading to cellular apoptosis resistance. The R337H mutation in TP53 is an example of the founder effect at work. The founder effect refers to the loss of genetic variation when a large population descends from a smaller population of fewer individuals. The descendants of the initial population are much more likely to harbour genetic variations that are less common in the species as a whole. In southern Brazil, the R337H mutation in p53 is present at an unusually high frequency 4 and is thought to have been introduced by European settlers several hundred years ago. It is responsible for a widespread incidence of early-onset breast cancers, LFS, and paediatric adrenocortical tumours. Interestingly, individuals with this mutation can trace their lineage back to the group of European settlers that set foot in Brazil hundreds of years ago. Studying p53 has enabled us to unveil its intricate web of interactions with other proteins and molecules within the cell and unlock the secrets of cancer development and potential therapeutic strategies. By restoring or mimicking the functions of p53, we may be able to provide cancer patients with some relief from this life-changing condition. Written by Malintha Hewa Batage Related articles: Zinc finger proteins / Anti-freeze proteins Project Gallery

A hereditary neurodegenerative disorder Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link Huntington's disease 27/09/25, 11:04 Last updated: Published: 18/10/23, 16:12 A hereditary neurodegenerative disorder Huntington’s disease (HD) is a neurodegenerative disorder causing cognitive decline, behavioural difficulties, and uncontrollable movements. It is a hereditary disease that has a devastating effect on the individual’s life and unfortunately is incurable. Genetic component What may come as a surprise, is that in everyone’s genetics there are two copies (one from each parent) of the Huntingtin’s gene coding for the Huntingtin protein. This gene is coded by CAG repeats. In healthy genes, the CAG sequence is repeated between 10 and 26 times. However, if the gene is faulty, CAG repeats over 40 times resulting in a dysfunctional Huntingtin protein. The disease is autosomal dominant meaning regardless of gender, if either parent is a carrier, their child has a 50% chance of inheriting the faulty gene. REMINDER: because the gene is dominant, it means those who inherit even one copy will develop the disease Effect on the brain The faulty Huntingtin protein accumulates in cells, leading to cell death and damage to the brain. If you were to look at the brains of individuals with Huntington’s Disease, you would see a reduction in volume of the caudate and putamen. These areas are part of the striatum, which is a subdivision of the basal ganglia, involved in fine tuning our voluntary movements, i.e., reaching out to grab a cup. As the disease progresses, this atrophy can extend to other areas of the brain including the thalamus, frontal lobe, and cerebellum. Symptoms The symptoms normally manifest in three categories: motor, cognitive and psychiatric. We know that the basal ganglia is involved in our voluntary movement, so the damage causes one of the most visible symptoms in HD- uncontrollable and jerky movements. Cognitive symptoms include personality changes, difficulties with planning and attention. There can also be impairments to how those with HD recognise emotions- all these symptoms can interact to make social interaction more difficult. Finally, the psychiatric symptoms often seen include irritability and aggression, depression, anxiety, and apathy. Impact on life and family At the age when diagnosis usually occurs (around 30 years old), patients are often buying houses, getting married and either having children or deciding to start a family. The diagnosis may change peoples outlook on having children and can put a great psychological burden on them if they have unknowingly passed it along to those already born. Diagnosis also brings consequences to seemingly mundane, but incredibly important issues such as gaining life insurance, with some companies not covering individuals with an official diagnosis. Subsequently this makes life harder for their families, as the patient will eventually be unable to work and there could be associated costs with the need for care facilities as the disease progresses. Unfortunately, this is a progressive neurodegenerative condition with no cure. The only treatment options available at present, are interventions which aim to alleviate the patients’ symptoms. Whilst these treatments will reduce the motor and psychiatric symptoms, they cannot stop the progression of Huntington’s disease. We have only scratched the surface on the impact Huntington’s disease has on a patient and their families. It is so important to understand ways in which everyone that is affected can be best supported during the disease progression, to give all those involved a better quality of life. Written by Alice Jayne Greenan Related articles: A potential gene therapy for HD / Epilepsy Project Gallery

Exploring the distinctive features that define and disrupt the brain Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link A deep dive into the hallmarks defining Alzheimer’s disease 08/07/25, 14:39 Last updated: Published: 06/11/24, 12:02 Exploring the distinctive features that define and disrupt the brain The progressive decline in neurocognition, resulting in a detrimental effect on one’s activities of daily living, is referred to as dementia. It typically affects people over the age of 65. Multiple theories have been proposed to explain the pathogenesis of Alzheimer’s disease (AD), including the buildup of amyloid plaques in the brain and the formation of neurofibrillary tangles (NFT) in cells. Understanding the pathophysiology of AD is imperative to the development of therapeutic strategies. Therefore, this article will outline the major hallmarks and mechanisms of AD. Hallmark 1: amyloid plaques One of the most widely accepted hypotheses for AD is the accumulation of amyloid beta protein (Aβ) in the brain. Aβ is a 4.2 kDa peptide consisting of approximately 40–42 amino acids, originating from a precursor molecule called amyloid precursor protein. This process, defined as amyloidosis, is strongly linked to brain aging and neurocognitive decline. How do the amyloid plaques form? See Figure 1 . Reasons for the accumulation of amyloid plaques: Decreased autophagy: Amyloid proteins are abnormally folded proteins. Autophagy in the brain is primarily carried out by neuronal and glial cells, involving key structures known as autophagosomes and lysosomes. When autophagy becomes downregulated, the metabolism of Aβ is impaired, eventually resulting in plaque buildup. Overproduction of acetylcholinesterase (AChE): Acetylcholine (Ach) is the primary neurotransmitter involved in memory, awareness, and learning. Overproduction of ACHE by astrocytes into the synaptic cleft can lead to excessive breakdown of Ach, with detrimental effects on cognition. Reduced brain perfusion: Blood flow delivers necessary nutrients and oxygen for cellular function. Reduced perfusion can lead to “intracerebral starvation”, depriving cells of the energy needed to clear Aβ. Reduced expression of low-density lipoprotein receptor-related protein 1: Low-density lipoprotein receptor-related protein 1 (LRP1) receptors are abundant in the central nervous system under normal conditions. They are involved in speeding up the metabolic pathway of Aβ by binding to its precursor and transporting them from the central nervous system into the blood, thereby reducing buildup. Reduced LRP1 expression can hinder this process, leading to amyloid buildup. Increased expression of the receptor for advanced glycation end products (RAGE): RAGE is expressed on the endothelial cells of the BBB, and its interaction with Aβ facilitates the entry of Aβ into the brain. Hallmark 2: neurofibrillary tangles See Figure 2 Neurofibrillary tangles are excessive accumulations of tau protein. Microtubules typically support neurons by guiding nutrients from the soma (cell body) to the axons. Furthermore, tau proteins stabilise these microtubules. In AD, signalling pathways involving phosphorylation and dephosphorylation cause tau proteins to detach from microtubules and stick to each other, eventually forming tangles. This results in a disruption in synaptic communication of action potentials. However, the exact mechanism remains unclear. Recent studies suggest an interaction between Aβ and tau, where Aβ can cause tau to misfold and aggregate, forming neurofibrillary tangles inside brain cells. Both Aβ and tau can self-propagate, spreading their toxic effects throughout the brain. This creates a vicious cycle, where Aβ promotes tau toxicity, and toxic tau can further exacerbate the harmful effects of Aβ, ultimately causing significant damage to synapses and neurons in AD. Hallmark 3: neuroinflammation Microglia are the primary phagocytes in the central nervous system. They can be activated by dead cells and protein plaques, where they initiate the innate immune response. This involves the release of chemokines to attract other white blood cells and the activation of the complement system which is a group of proteins involved in initiating inflammatory pathways to fight pathogens. In AD, microglia bind to Aβ via various receptors. Due to the substantial accumulation of Aβ, microglia are chronically activated, leading to sustained immune responses and neuroinflammation. Conclusion The contributions of amyloid beta plaques, neurofibrillary tangles and chronic neuroinflammation provide a framework for understanding the pathophysiology of AD. AD is a highly complex condition with unclear mechanisms. This calls for the need of continued research in the area as it is crucial for the development of effective treatments. Written by Blessing Amo-Konadu Related articles: Alzheimer's disease (an overview) / CRISPR-Cas9 to potentially treat AD / Sleep and memory loss REFERENCES 2024 Alzheimer’s Disease Facts and Figures. (2024). Alzheimer’s & dementia, 20(5). doi:https://doi.org/10.1002/alz.13809. A, C., Travers, P., Walport, M. and Shlomchik, M.J. (2001). The complement system and innate immunity. [online] Nih.gov. Available at: https://www.ncbi.nlm.nih.gov/books/NBK27100/ . Bloom, G.S. (2014). Amyloid-β and tau: the Trigger and Bullet in Alzheimer Disease Pathogenesis. JAMA neurology, [online] 71(4), pp.505–8. doi:https://doi.org/10.1001/jamaneurol.2013.5847. Braithwaite, S.P., Stock, J.B., Lombroso, P.J. and Nairn, A.C. (2012). Protein Phosphatases and Alzheimer’s Disease. Progress in molecular biology and translational science, [online] 106, pp.343–379. doi:https://doi.org/10.1016/B978-0-12-396456-4.00012-2. Heneka, M.T., Carson, M.J., El Khoury, J., Landreth, G.E., Brosseron, F., Feinstein, D.L., Jacobs, A.H., Wyss-Coray, T., Vitorica, J., Ransohoff, R.M., Herrup, K., Frautschy, S.A., Finsen, B., Brown, G.C., Verkhratsky, A., Yamanaka, K., Koistinaho, J., Latz, E., Halle, A. and Petzold, G.C. (2015). Neuroinflammation in Alzheimer’s disease. The Lancet. Neurology, 14(4), pp.388–405. doi:https://doi.org/10.1016/S1474-4422(15)70016-5. Kempf, S. and Metaxas, A. (2016). Neurofibrillary Tangles in Alzheimer′s disease: Elucidation of the Molecular Mechanism by Immunohistochemistry and Tau Protein phospho- proteomics. Neural Regeneration Research, 11(10), p.1579. doi:https://doi.org/10.4103/1673-5374.193234. Kumar, A., Tsao, J.W., Sidhu, J. and Goyal, A. (2022). Alzheimer disease. [online] National Library of Medicine. Available at: https://www.ncbi.nlm.nih.gov/books/NBK499922/. Ma, C., Hong, F. and Yang, S. (2022). Amyloidosis in Alzheimer’s Disease: Pathogeny, Etiology, and Related Therapeutic Directions. Molecules, 27(4), p.1210. doi:https://doi.org/10.3390/molecules27041210. National Institute on Aging (2024). What Happens to the Brain in Alzheimer’s Disease? [online] National Institute on Aging. Available at: https://www.nia.nih.gov/health/alzheimers-causes-and-risk-factors/what-happens-brain- alzheimers-disease. Stavoe, A.K.H. and Holzbaur, E.L.F. (2019). Autophagy in Neurons. Annual Review of Cell and Developmental Biology, 35(1), pp.477–500. doi: https://doi.org/10.1146/annurev-cellbio-100818-125242 . Project Gallery

The emperor penguin's life cycle is intertwined with sea ice freezing and melting over the year Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link Emperor penguins, the kings of the ice Last updated: 29/05/25, 10:38 Published: 24/04/25, 07:00 The emperor penguin's life cycle is intertwined with sea ice freezing and melting over the year This is article no. 6 in a series on animal conservation. Next article: Protecting rock-wallabies in Australia . Previous article: Gorongosa National Park . In November 2024, a malnourished emperor penguin was spotted in Australia, over 2000 miles from its home in Antarctica. It is said to be the furthest north a wild emperor has ever been seen. While scientists do not know why or how the penguin ended up there, it sparked conversations about climate change and the survival of this fascinating species. This article will describe the characteristics of the emperor penguin, and how climate change could affect it. Introduction to emperor penguins Emperor penguins ( Aptenodytes forsteri ) are the largest living penguin species, weighing 20-40 kilograms and standing about 1 metre tall. It is estimated that there are 256,000 breeding pairs of emperor penguins across 54 colonies, which are spread out along the entire coast of Antarctica. Their diet consists of krill, fish, and squid - and they can dive over 500m deep to find food. Emperor penguins are the only warm-blooded animal to breed during the Antarctic winter, one of the world's coldest and darkest times of the year. Therefore, they are adapted to the cold days, harsh winds, and high water pressure in which they live. For example, they have over 20 kinds of feathers - some of which help with waterproofing while swimming, and others help with thermal insulation. Many penguin species huddle together as juveniles to conserve body heat, but emperors are the only species to do so as adults. Thus, emperor penguins are a unique and ecologically fascinating species. Life cycle and fast ice The emperor penguin's life cycle is intertwined with sea ice freezing and melting over the year ( Figure 1 ). For most of the year, emperors live on fast ice, which are ice sheets floating on the sea but attached to the coast. The first reason they need fast ice is moulting, when emperor penguins replace all their feathers in late summer. They moult on ice because they cannot swim until their new layer of waterproof feathers has grown. Emperor penguins return to fast ice at the onset of winter to mate, lay eggs, and raise chicks. While one parent stays on the fast ice to look after the chick, the other parent goes to sea to find food for the family. The chick grows waterproof adult feathers for fast ice to break up in summer. At this point, the penguins live at sea until moulting time. This way, emperor penguin survival is linked to fast ice availability. Threat from climate change Because emperor penguins are so heavily dependent on fast ice, scientists are concerned about the potential impacts of global warming. Rising sea surface temperatures mean fast ice may not form long enough in the year for emperor penguins to complete their life cycle. In late 2022, sea ice was dramatically reduced in the Bellingshausen Sea in Antarctica, and 4 of the 5 nearby emperor penguin colonies had a failed breeding season. These failed seasons may become more common in the future with climate change. A 2020 study predicted that in the worst case climate scenario, 80% of penguin colonies will see population declines of over 90% by 2100. If international climate targets are met, only 19% of colonies are expected to decline that badly ( Figure 2 ). Because the International Union for Conservation of Nature classified emperors as Near Threatened, they do not meet Antarctica's criteria for being a protected species. Scientists have requested this conservation status be upgraded to better reflect the inability of emperor penguins to adapt or disperse away from the effects of climate change. Emperor penguins face no threats from humans other than global warming, so reducing greenhouse gas emissions is crucial to protect them. Conclusion Emperor penguins are charismatic creatures with unique adaptations to live during the cold Antarctic winter. Their survival is strongly linked to the availability of sea ice because they moult, breed, and care for their offspring on ice sheets. Global warming is making these ice sheets disappear, so emperor penguins must be monitored and protected to ensure survival through a changing climate. Written by Simran Patel Related articles: The Arctic Springtail / California Condors / Brain-climate connection REFERENCES CBS News. (2024) Malnourished emperor penguin that swam ashore in Australia 2,000 miles from home a quandary for rescuers. CBS News . Available from: https://www.cbsnews.com/news/emperor-penguin-australia-2000-miles-from-antarctic-ice-melting-climate-change/ (Accessed 11th November 2024). Fretwell, P.T., Boutet, A. & Ratcliffe, N. (2023) Record low 2022 Antarctic sea ice led to catastrophic breeding failure of emperor penguins. Communications Earth & Environment . 4 (1): 1–6. Garnier, J., Clucas, G., Younger, J., Sen, B., Barbraud, C., Larue, M., Fraser, A.D., Labrousse, S. & Jenouvrier, S. (2023) Massive and infrequent informed emigration events in a species threatened by climate change: the emperor penguins . Available from: https://hal.science/hal-03822288 (Accessed 10th November 2024). Hooper, S. (11th November 2024) Experts baffled after penguin shows up on beach 2,200 miles away from home Metro . Available from: https://metro.co.uk/2024/11/11/experts-baffled-penguin-shows-beach-2-200-miles-away-home-21970144/ (Accessed 11th November 2024). Jenouvrier, S. et al. (2020) The Paris Agreement objectives will likely halt future declines of emperor penguins. Global Change Biology . 26 (3): 1170–1184. Labrousse, S., Nerini, D., Fraser, A.D., Salas, L., Sumner, M., Le Manach, F., Jenouvrier, S., Iles, D. & LaRue, M. (2023) Where to live? Landfast sea ice shapes emperor penguin habitat around Antarctica. Science Advances . 9 (39): eadg8340. LaRue, M. et al. (2024) Advances in remote sensing of emperor penguins: first multi-year time series documenting trends in the global population. Proceedings of the Royal Society B: Biological Sciences . 291 (2018): 20232067. Le Maho, Y. (1977) The Emperor Penguin: A Strategy to Live and Breed in the Cold: Morphology, physiology, ecology, and behavior distinguish the polar emperor penguin from other penguin species, particularly from its close relative, the king penguin. American Scientist . 65 (6): 680–693. Trathan, P.N. et al. (2020) The emperor penguin - Vulnerable to projected rates of warming and sea ice loss. Biological Conservation . 241: 108216. Williams, C.L., Hagelin, J.C. & Kooyman, G.L. (2015) Hidden keys to survival: the type, density, pattern and functional role of emperor penguin body feathers. Proceedings of the Royal Society B: Biological Sciences . 282 (1817): 20152033. Project Gallery

Unmasking the complexities of the condition Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link Crohn's disease 09/07/25, 14:01 Last updated: Published: 22/03/24, 20:16 Unmasking the complexities of the condition Introduction Crohn's disease is a chronic inflammatory condition that primarily targets the gastrointestinal tract. While it commonly afflicts individuals aged 20 to 50, it can also manifest in children and older adults, albeit less frequently. Symptoms of Crohn's disease vary widely and may include skin lesions spanning from the mouth to the anus, along with prevalent issues such as diarrhoea, abdominal pain, weight loss, rectal bleeding, fatigue, and fever. Diagnosis Diagnosing Crohn's disease can be challenging due to its similarity to other conditions. However, specific symptoms like bloody diarrhoea, iron deficiency, and unexplained weight loss are significant indicators that warrant further investigation by a gastroenterologist. Many tests that can confirm Crohn’s disease: Endoscopy: endoscopy, including procedures like colonoscopy and upper endoscopy, is a dependable method for diagnosing Crohn's disease and distinguishing it from other conditions with similar symptoms. During an endoscopy, a thin tube called an endoscope is inserted into the rectum to visually inspect the entire gastrointestinal tract and collect small tissue samples for further analysis. Imaging: Computed tomography (CT), magnetic resonance imaging (MRI), and ultrasonography are valuable tools for assessing disease activity and detecting complications associated with Crohn's disease. These imaging techniques can examine areas of the gastrointestinal tract that may not be accessible via endoscopy, providing comprehensive insights into the condition's progression and associated issues. Laboratory testing: various laboratory tests, including complete blood count, C-reactive protein levels, pregnancy tests, and stool samples, are conducted to screen for Crohn's disease. These tests are typically the initial step in diagnosis, helping to avoid the necessity for more invasive procedures like endoscopies and imaging. Additionally, laboratory testing may involve assessing inflammatory markers such as erythrocyte sedimentation rate (ESR) and faecal calprotectin to further aid in diagnosis and monitoring of the condition. Treatment and prevention While there is currently no cure for Crohn’s disease, numerous treatments have been developed over time to effectively manage symptoms and sometimes even induce remission. When determining a treatment plan for patients, factors such as age, specific symptoms, and the severity of inflammation are taken into careful consideration. Corticosteroids and immunomodulators are medications commonly used to manage Crohn’s disease. Corticosteroids work by reducing inflammation and suppressing the immune system, typically employed to address flare-ups due to their rapid action. However, they are not suitable for long-term use as they may lead to significant side effects. In contrast, maintenance therapy often involves immunomodulators such as azathioprine, methotrexate, or biologic agents like anti-TNF drugs (such as infliximab or adalimumab). These medications target specific immune pathways to enhance the effectiveness of the immune system. Research indicates that immunomodulators are associated with fewer adverse effects compared to corticosteroids and are effective in maintaining remission. Monoclonal antibody treatment is another approach used to manage symptoms and sustain remission in Crohn's disease. These therapies are categorised as biologic treatments, targeting precise molecules involved in inflammation and the immune response. Despite carrying certain risks, such as infections, the likelihood of developing cancer with these treatments is typically deemed low. Crohn’s disease frequently leads to complications that may necessitate surgical intervention. Gastrointestinal surgeries can greatly alleviate symptoms and enhance the quality of life for patients. However, surgery is usually considered only when medical therapy proves insufficient in controlling the disease or when complications arise. Although the exact cause of Crohn’s disease remains uncertain, factors such as genetics, immune system dysfunction, and environmental influences are believed to contribute to its development. While there is no definitive evidence pinpointing specific causative factors, numerous studies suggest potential links to an unhealthy diet and lifestyle, dysbiosis (imbalance of healthy and unhealthy gut bacteria), smoking, and a family history of the disease. Therefore, it is crucial to minimise exposure to these risk factors in order to decrease the likelihood of developing Crohn’s disease. Written by Sherine Abdul Latheef Related articles: the gut microbiome / the dopamine connection / Diverticular disease / Mesenchymal stem cells REFERENCES Veauthier B, Hornecker JR. Crohn's Disease: Diagnosis and Management. Am Fam Physician. 2018;98(11):661-669. Torres J, Mehandru S, Colombel JF, Peyrin-Biroulet L. Crohn's disease. Lancet. 2017;389(10080):1741-1755. doi:10.1016/S0140-6736(16)31711-1 Mills SC, von Roon AC, Tekkis PP, Orchard TR. Crohn's disease. BMJ Clin Evid. 2011;2011:0416. Published 2011 Apr 27. Sealife, A. (2024) Crohn’s disease, Parkland Natural Health. Available at: https://wellness-studio.co.uk/crohns-disease/ (Accessed: 09 March 2024). How to stop anxiety stomach pain & cramps (2022) Calm Clinic - Information about Anxiety, Stress and Panic. Available at: https://www.calmclinic.com/anxiety/symptoms/stomach-pain (Accessed: 09 March 2024). Project Gallery

When misfolded proteins lead to disease Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link Unfolding prion diseases and their inheritance 22/04/25, 14:11 Last updated: Published: 06/03/24, 11:32 When misfolded proteins lead to disease This is article no. 5 in a series on rare diseases. Next article: Neuromyelitis optica . Previous article: Epitheliod hemangioendothelioma . Prion proteins are found abundantly in the brain; their function is unclear, but they are involved in a multitude of physiological mechanisms, including myelin homeostasis and the circadian rhythm. Correctly folded prion proteins in the cellular form are termed PrP C , while their infectious isoform is called PrP Sc . As shown in Figure 1, the misfolded PrP Sc is largely made up of β-pleated sheets instead of α-helices; PrP Sc is prone to forming aggregates that cause transmissible spongiform encephalopathies (TSEs). Prion diseases can be categorised by their aetiology: acquired, sporadic, and hereditary. Acquired prion diseases are caused by the inadvertent introduction of PrP Sc prions into an individual. Sporadic prion diseases are the most common type, where PrP C misfolds into PrP Sc for an unknown reason and propagates this misfolding within other prion proteins. Hereditary prion diseases are caused by genetic mutation of the human prion protein gene (PRNP), which causes misfolding into the infectious isoform. Consequently, these mutations can be passed to offspring, resulting in the same misfolding and disease. Interestingly, different types of PRNP mutations cause different types of prion diseases. Creutzfeldt-Jakob disease (CJD) is a type of TSE found in humans which causes mental deterioration and involuntary muscle movement; symptoms tend to worsen as the disease progresses, making it a degenerative disorder. Familial CJD (fCJD) is a rare type of hereditary prion disease and can sometimes result in a faster rate of disease progression compared to sporadic cases. Due to a dominant inheritance pattern, relatives of fCJD patients are often also affected by the disease. The most common mutation observed in familial CJD is an E200K mutation denoting the substitution of glutamic acid with lysine in the prion protein. Other common mutations resulting in fCJD include mutations at positions 178 and 210 on the prion protein. However, there are, less frequently, a multitude of other mutations correlated with familial CJD development. Familial CJD can be caused by STOP codon mutations, which result in a truncated protein, some of which show similar pathology to Alzheimer’s disease, such as Q16OX and Q227X. fCJD can also be caused by insertional mutations, possibly caused by unbalanced crossover and recombination. The prion protein consists of a nona-peptide (made up of nine amino acids) followed by four repeats of an octa-peptide (made up of eight amino acids). During insertion mutations, additional repeats of the octa-peptide are present in the prion protein. Interestingly, different numbers of inserts result in different pathological characteristics; patients with 1, 2 or 4 extra repeats show similarity to sporadic CJD, while those with 5-9 extra repeats show similarity to Gerstmann-Sträussler-Scheinker syndrome. Hereditary prion diseases are important to study in order to develop an understanding of not only prion misfolding diseases but also diseases associated with misfolding of other proteins, such as Alzheimer’s and Parkinson’s. Understanding the mechanisms of hereditary prion diseases will aid the development of treatments for such conditions. In particular, observing and investigating particular genetic mutations observed to play a part in prion misfolding is crucial alongside using genetic information to infer the risk of disease an individual may have. Written by Isobel Cunningham Project Gallery