MAP1LC3A

Researchers describe a natural product-like molecule, Tantalosin, that inhibits interaction between two proteins in complexes that reshape membranes inside the cell. The findings lead to a deeper understanding of how membrane remodeling works in human cells and future development of new drugs. In a study published in PNAS, Umeå researchers describe a natural product-like molecule, Tantalosin, that inhibits interaction between two proteins in complexes that reshape membranes inside the cell. The findings lead to a deeper understanding of how membrane remodelling works in human cells and future development of new drugs. "Our study is a good case to use small molecules as valuable chemical tools for understanding complex biological mechanisms. I am happy to coordinate a fantastic collaboration with colleagues in Umeå, Stockholm and Germany," says Yaowen Wu, professor at the Department of Chemistry at Umeå University. Membranes of cells are made of lipids and proteins, and they serve barrier functions for cells and intracellular organelles. Membranes of cells are highly dynamic mosaic-fluid structures that undergo constant reshaping. The endosomal sorting complex required for transport (ESCRT) is tasked with remodelling membranes inside the cell. The ESCRT machinery assembles at the site in the cell where membranes need deformation and then forms helical protein polymers that can contract and pinch off cell membranes. Previously, Professor Yaowen Wu and his group, in collaboration with Professor Herbert Waldmann's laboratory at Max Planck Institute Dortmund in Germany, identified a chemical molecule, Tantalosin, that induces a phenotype like autophagy -- a self-eating process in the cell. Tantalosin is a synthetic molecule inspired by alkaloids from the medical plant Cinchona. They observed a very interesting phenomenon in the cell treated with Tantalosin and investigated further the molecular mechanism how Tantalosin works in the cell. In collaboration with the chemical proteomics core facility at SciLifeLab in Karolinska Institute the team scrutinized potential cellular targets of Tantalosin. "To our surprise, we found that none of the autophagy-related proteins were on the list of potential targets. However, IST1 protein in ESCRT complexes was identified and validated as the cellular target of Tantalosin. We were excited to work on deciphering this unexpected connection between ESCRT complexes and autophagy," says first author Anastasia Knyazeva, who just recently completed her doctoral degree at the Department of Chemistry at Umeå University. The researchers characterized the mechanism using a range of biochemical and cell biological methods. When they studied protein-protein interaction in solution, they found that Tantalosin completely stops the interaction between IST1 and its binding partner CHMP1B. "We then took a closer look at these two proteins using a transmission electron microscope in collaboration with Kasturika Shankar, a PhD student from Lars-Anders Carlson's lab at Umeå University. Intriguingly, Tantalosin disrupts the formation of ordered IST1-CHMP1B filaments," explains Shuang Li, the paper's co-first author and postdoctoral fellow at the Department of Chemistry at Umeå University. Furthermore, the researchers looked inside the cell and found that Tantalosin rapidly disrupts the recycling of cell-surface receptors back to the cell surface. This property could be potentially beneficial for treating certain types of cancers that are driven by cell-surface receptors. In this study, the researchers found that LC3 protein, which is usually a hallmark of autophagy, is linked to the endosomal membranes during Tantalosin treatment. Interestingly, the canonical autophagic degradation was not observed. Instead, they found that the process follows a noncanonical autophagy pathway. "We believe that Tantalosin can be a unique molecule that facilitates understanding new functions of noncanonical conjugation of LC3 to endosomal membranes. We hope that further studies will reveal the role of LC3-membrane conjugation and its associated proteins in membrane deformation processes," says Anastasia Knyazeva.

Fragile X syndrome (FXS) is the most common genetic cause of intellectual disabilities and a major genetic factor for autism spectrum disorder (ASD). It is characterized by deficits in executive function, learning difficulties, and social anxiety. A recent study has found that elevated levels of the protein MAP1B result in neuronal autophagy defects closely linked to human ASD. Treating FXS and ASD with rapamycin, a drug that inhibits autophagy, may be a promising potential therapy. As Synapse database indicates, the drug is currently being used for immune System Diseases, neoplasms, congenital Disorders, digestive System Disorders, among many other conditions, but none of the behavioral disorders. The lack of FMRPThe study observed that, without enough fragile X messenger ribonucleoprotein 1 protein (FMRP), MAP1B levels increase, impairing dendritic development and neuronal activity in humans. Compared to control cortical neurons infected with LV-shNC, MAP1B expression was significantly higher in cortical neurons infected with LV-shFMR1. Human neurons with elevated MAP1B levels exhibited significantly reduced dendritic complexity, total dendritic length, and increased excitability when compared to control neurons. These might suggest that FMR1 knockdown leads to overexpression of MAP1B, which correlates with dendritic abnormalities and overexcitability in human cortical neurons. Elevated MAP1B level leads to impaired dendritic development and altered electrophysiology of human neurons.Whole-cell patch clamp recordings were conducted to evaluate the intrinsic excitability of neurons. MAP1B neurons required less injected current to elicit action potentials (lower rheobase current), and the response to current injection showed a higher peak frequency compared to neurons without elevated MAP1B levels, consistent with the increased excitability measured by MEA. Synaptic transmission in these neurons was further evaluated by recording miniature excitatory postsynaptic currents (mEPSCs). Compared to control neurons, the study found a decrease in the frequency and amplitude of mEPSCs in MAP1B neurons, which may be due to impaired dendritic maturation. Therefore, elevated levels of MAP1B lead to neuronal overexcitability and impaired synaptic transmission in human neurons.  It seems the lack of FMRP leads to an increase in MAP1B levels, which impairs the morphology and electrophysiological maturation of human neurons.  MAP1B and ASD-like social behavior The study also revealed that MAP1B transcript levels were significantly higher in the ASD population compared to the normal population, but not in the BPD or SCZ population. This suggests that MAP1B may be a convergent molecular feature of FXS and ASD. To investigate the potential impact of increased MAP1B expression in the PFC on ASD and FXS-related behaviors in mice, further evaluations were conducted. The results demonstrated that MAP1B in excitatory neurons in the PFC contributes to the social behavior deficits observed in FXS and ASD. Additionally, elevated levels of MAP1B were found to impair neuronal autophagy. These findings suggest a potential mechanism underlying the neurological abnormalities observed in individuals with FXS and ASD and provide insight into potential therapeutic targets for these disorders. Elevated MAP1B level leads to autism-like behaviors.To investigate the molecular mechanisms of MAP1B on dendritic development and behavior, the study used the BioGRID database to identify various autophagy-related proteins that interact with MAP1B. The study first observed that overexpression of MAP1B led to a reduction in LC3, and protein blot analysis showed that the level of LC3-II in neurons overexpressing MAP1B was lower than that in control cells, while the level of LC3-I was unchanged, indicating that MAP1B affects autophagosome formation rather than autophagosome-lysosome fusion. The same result was obtained by inhibiting autophagosome-lysosome fusion with bafilomycin A1 (BafA1). Elevated MAP1B level leads to autophagy deficits in mouse neurons.Autophagy defects observed in primary mouse neurons with MAP1B overexpression were due to a reduction in autophagosome formation rather than autophagosome-lysosome fusion. That is, a decrease in autophagosome formation is a common cause of impaired cellular autophagy. Autophagosomes deliver proteins and organelles to lysosomes for degradation through cargo adapter proteins such as p62. When autophagosome formation is reduced, the final degradation step is also reduced, resulting in the accumulation of p62.  Compared to the control group, p62 expression increased in neurons overexpressing MAP1B. MAP1B and LC3 proteinGFP-LC3 fusion protein from cells overexpressing MAP1B pulled more MAP1B and less ATG7, compared to control neurons, suggesting an increased interaction between MAP1B and LC3, but a decreased interaction between ATG7 and LC3 in cells overexpressing MAP1B. MAP1B overexpression can isolate cell LC3-I, thereby reducing its lipidation and promoting its interaction with MAP1B, rather than with ATG7, which impairs autophagosome formation and leads to autophagy defects. Elevated MAP1B sequesters LC3 and prevents its lipidation in neurons.Furthermore, the study explored whether rapamycin, an autophagy enhancer, could alleviate the deficits caused by MAP1B overexpression. The results demonstrated that rapamycin treatment restored dendritic complexity and total dendritic length in neurons overexpressing MAP1B. Additionally, rapamycin treatment alleviated the social behavior deficits in mice resulting from MAP1B overexpression in the PFC. These findings suggest that the use of autophagy enhancers such as rapamycin may hold therapeutic potential for FXS and ASD, which are associated with MAP1B-related autophagy defects. This study provides evidence that increased MAP1B levels can negatively impact neuronal development and social behavior through the autophagy pathway, which is associated with FXS and ASD. The findings shed light on the molecular mechanisms underlying these disorders and suggest that rapamycin represents a promising potential therapy for FXS and ASD. References: Levine JE, Wang D, Chang Q, Zhao X. Elevated levels of FMRP-target MAP1B impair human and mouse neuronal development and mouse social behaviors via autophagy pathway. Nat Commun. 2023 Jun 26;14(1):3801.

Statistically significant decreased levels of novel biomarker AGO2 (p= 0.002) observed in newly diagnosed people living with Parkinson's disease (PD) compared to healthy individuals NeuroSense's combination platform has been observed in a clinical trial to induce an increase of AGO2 in ALS patients, indicating therapeutic potential in PD NeuroSense is exploring co-development of PD asset with potential collaborators CAMBRIDGE, Mass., May 2, 2023 /PRNewswire/ -- NeuroSense Therapeutics Ltd. (Nasdaq: NRSN) ("NeuroSense"), a company developing treatments for severe neurodegenerative diseases, today announced positive preliminary results from a novel biomarker study conducted to evaluate the potential of NeuroSense's combination platform therapy for the treatment of Parkinson's disease (PD), the second most common neurodegenerative disorder. This study compared blood samples from 30 healthy individuals to 30 people living with PD by utilizing neuronal derived exosomes to identify modulations in PD-associated biomarkers, including AG02. AGO2 (Argonaute 2), the catalytic subunit of the protein complex responsible for RNA-induced silencing,1 was shown to be critical to the regulation of alpha-synuclein (αSyn) accumulation in dopaminergic neurons of the substantia nigra pars compacta, the region of the brain that is responsible for motor control.2 The dysregulation of αSyn through dysfunction of AGO2 can have detrimental effects in the brain, which can lead to PD. In the PD biomarker study, NeuroSense observed a statistically significant (p= 0.002) decrease in levels of AGO2 in newly diagnosed PD patients (n=15) when compared to the healthy control group. There were no significant changes observed in AGO2 levels of more advanced stage PD patients, indicating this trend could be related to disease onset. In a Phase 2a clinical trial conducted in people living with amyotrophic lateral sclerosis (ALS), NeuroSense's platform combination therapy was observed to induce a statistically significant (p= 0.039) increase of AGO2 and also showed a trend of increased levels of LC3 (p= 0.054). LC3 is an essential protein involved in autophagy,3 a cellular recycling process utilized to degrade aggregated proteins and damaged organelles, which has been reported to be involved in many neurodegenerative disorders, including PD. In the PD biomarker study NeuroSense observed a change in levels of LC3, which decreased in newly diagnosed PD patients (p= 0.034), suggesting an impairment in cellular recycling processes. Other biomarkers that were measured, including some PD-specific markers, did not reveal trends and may be revisited in future studies. "We believe these results strengthen the scientific rationale to develop NeuroSense's platform technology for PD, as the mechanism of action may be helpful in targeting disease-specific pathways, specifically AGO2 dysregulation," stated Dr. Shiran Zimri, NeuroSense's VP of R&D. "We intend to further evaluate these findings, as well as explore additional biomarkers and their involvement in the progression and pathology of PD in future studies." Prof. Roy Alcalay M.D., Chief of the Movement Disorders Center at Tel-Aviv Sourasky Medical Center, who participated in conducting the PD biomarker study, commented, "We are excited by this interesting collaboration and look forward to continuing our work together." "We believe that these data denote the potential of NeuroSense's platform technology to target early stages of Parkinson's disease. This is particularly relevant as early detection of PD is becoming more common," stated NeuroSense's CEO, Alon Ben-Noon. "Based on these encouraging results, we are now looking to co-develop our PD asset with collaborators that have a core focus on Parkinson's." About Parkinson's Disease Parkinson's disease (PD) is the second most common neurogenerative condition after Alzheimer's disease. Nearly 1 million people in the U.S. and an estimated 10 million people worldwide are living with PD. Characterized by uncontrollable movements, difficulty with balance and coordination, as well fatigue, depression, and memory difficulties, these symptoms begin to occur when dopaminergic neurons in the substantia nigra become impaired and die. The global PD treatment market was valued at $5.7 billion in 2021 and is projected to reach $10.4 billion by 2031, growing at a CAGR of 6.2%. About AGO2 AGO2 is a protein-coding gene essential for miRNA function. It is involved in the regulation of alpha-synuclein (αSyn) biogenesis. As obtained in cultures and cell tissues alike, depletion of AGO2 leads to αSyn accumulation. In pre-clinical studies, an increase in αSyn mRNA and protein expression was observed when AGO2 is knocked-out. The dysregulation of αSyn through dysfunction of AGO2 can have detrimental effects in the brain, resulting in PD.2 About LC3 LC3, microtubule-associated protein 1A/1B-light chain 3, is an essential protein involved in autophagosome biogenesis/maturation, as well as an adaptor protein for selective autophagy.3 The most prevalent pathological features of many neurodegenerative diseases are the aggregation of misfolded proteins and the loss of neurons. Autophagy, utilized to degrade aggregated proteins and damaged organelles, has been reported to be involved in the occurrence of pathological changes in many neurodegenerative disorders, including Alzheimer's disease, Parkinson's disease, Huntington's disease and amyotrophic lateral sclerosis (ALS).4Therefore, LC3 has been widely used to monitor the number of autophagosomes as well as autophagic activity.3 About NDEs NeuroSense's biomarker study utilized neuronal-derived exosomes (NDEs) extracted from plasma. NDEs are small extracellular vesicles (EVs) generated by neurons that encapsulate a variety of molecules such as proteins, nucleic acids, and metabolites. ExoSORT™ by NeuroDex was used to identify NDEs in this biomarker study. Identification of NDEs and their cargo in body fluids can facilitate the discovery of new biomarkers for prognosis and therapy, as these vesicles can pass the blood-brain barrier (BBB) and provide a depiction of the current physiological status of neurons in the brain. About NeuroSense NeuroSense Therapeutics, Ltd. is a clinical-stage biotechnology company focused on discovering and developing treatments for patients suffering from debilitating neurodegenerative diseases. NeuroSense believes that these diseases, which include amyotrophic lateral sclerosis (ALS), Alzheimer's disease and Parkinson's disease, among others, represent one of the most significant unmet medical needs of our time, with limited effective therapeutic options available for patients to date. Due to the complexity of neurodegenerative diseases and based on strong scientific research on a large panel of related biomarkers, NeuroSense's strategy is to develop combined therapies targeting multiple pathways associated with these diseases. For additional information, we invite you to visit our website and follow us on LinkedIn and Twitter. Forward-Looking Statements This press release contains "forward-looking statements" that are subject to substantial risks and uncertainties. All statements, other than statements of historical fact, contained in this press release are forward-looking statements. Forward-looking statements contained in this press release may be identified by the use of words such as "anticipate," "believe," "contemplate," "could," "estimate," "expect," "intend," "seek," "may," "might," "plan," "potential," "predict," "project," "target," "aim," "should," "will" "would," or the negative of these words or other similar expressions, although not all forward-looking statements contain these words. Forward-looking statements are based on NeuroSense Therapeutics' current expectations and are subject to inherent uncertainties, risks and assumptions that are difficult to predict and include statements regarding the co-development of our PD assets with collaborators with a core focus on Parkinson's. Further, certain forward-looking statements are based on assumptions as to future events that may not prove to be accurate. Forward-looking statements are subject to a number of risks and uncertainties, including a delay in the reporting of top-line results from our ALS Phase 2b clinical trial, the risk that the final results of Parkinson's Disease (PD) Biomarker Study will not be consistent with the preliminary results and the risk that we will not be successful in signing co-development agreement or other agreements with collaborators with a core focus on Parkinson's. The future events and trends may not occur and actual results could differ materially and adversely from those anticipated or implied in the forward looking statements. You should not rely on these statements as representing our views in the future. More information about the risks and uncertainties affecting the Company is contained under the heading "Risk Factors" in the Annual Report on Form 20-F filed with the Securities and Exchange Commission on March 22, 2023. Forward-looking statements contained in this announcement are made as of this date, and NeuroSense Therapeutics Ltd. undertakes no duty to update such information except as required under applicable law. 1 O'Carroll, D. & Schaefer, A. General Principals of miRNA Biogenesis and Regulation in the Brain. Neuropsychopharmacology 38, 39-54, doi:10.1038/npp.2012.87 (2013). 2 Hernandez, S. M. et al. Unexpected Implication of SRP and AGO2 in Parkinson's Disease: Involvement in Alpha-Synuclein Biogenesis. Cells 10, doi:10.3390/cells10102792 (2021). 3 Lee, Y. K. & Lee, J. A. Role of the mammalian ATG8/LC3 family in autophagy: differential and compensatory roles in the spatiotemporal regulation of autophagy. BMB reports 49, 424-430, doi:10.5483/bmbrep.2016.49.8.081 (2016). 4 Guo, F., Liu, X., Cai, H. & Le, W. Autophagy in neurodegenerative diseases: pathogenesis and therapy. Brain pathology (Zurich, Switzerland) 28, 3-13, doi:10.1111/bpa.12545 (2018). Company Codes: NASDAQ-NMS:NRSN