Post-translational Modifications of α-Synuclein, their Therapeutic Potential and Crosstalk in Health and Neurodegenerative Diseases.

α-Synuclein (α-Syn) aggregation in Lewy bodies and Lewy neurites has emerged as a key pathogenetic feature in Parkinson's disease (PD), Dementia with Lewy Bodies and Multiple System Atrophy. Various factors, including post-translational modifications (PTMs), can influence the propensity of α-Syn to misfold and aggregate. PTMs are biochemical modifications of a protein that occur during or after translation and are typically mediated by enzymes. PTMs modulate several characteristics of proteins including their structure, activity, localization, and stability. α-Syn undergoes various post-translational modifications, including phosphorylation, ubiquitination, SUMOylation, acetylation, glycation, O-GlcNAcylation, nitration, oxidation, polyamination, arginylation, and truncation. Different PTMs of a protein can physically interact with one another or work together to influence a particular physiological or pathological feature in a process known as PTMs crosstalk. The development of detection techniques for the co-occurrence of PTMs in recent years has uncovered previously unappreciated mechanisms of their crosstalk. This has led to the emergence of evidence supporting an association between α-Syn PTMs crosstalk and synucleinopathies. In this review, we provide a comprehensive evaluation of α-Syn PTMs, their impact on misfolding and pathogenicity, the pharmacological means of targeting them, and their potential as biomarkers of disease. We also highlight the importance of the crosstalk between these PTMs in α-Syn function and aggregation. Insight into these PTMS and the complexities of their crosstalk can improve our understanding of the pathogenesis of synucleinopathies and identify novel targets of therapeutic potential. Significance Statement α-Synuclein as a key pathogenic protein in Parkinson's disease and other synucleinopathies, making it a leading therapeutic target for disease modification. Multiple post-translational modifications occur at various sites in α-Synuclein and alter its biophysical and pathological properties, some interacting with one another to add to the complexity of the pathogenicity of this protein. This review details these modifications, their implications in disease and potential therapeutic opportunities.

Molecular mechanism and potential therapeutic targets of necroptosis and ferroptosis in Alzheimer's disease.

Alzheimer's disease (AD), a neurodegenerative condition, is defined by neurofibrillary tangles, amyloid plaques, and gradual cognitive decline. Regardless of the advances in understanding AD's pathogenesis and progression, its causes are still contested, and there are currently no efficient therapies for the illness. The post-mortem analyses revealed widespread neuronal loss in multiple brain regions in AD, evidenced by a decrease in neuronal density and correlated with the disease's progression and cognitive deterioration. AD's neurodegeneration is complicated, and different types of neuronal cell death, alone or in combination, play crucial roles in this process. Recently, the involvement of non-apoptotic programmed cell death in the neurodegenerative mechanisms of AD has received a lot of attention. Aberrant activation of necroptosis and ferroptosis, two newly discovered forms of regulated non-apoptotic cell death, is thought to contribute to neuronal cell death in AD. In this review, we first address the main features of necroptosis and ferroptosis, cellular signaling cascades, and the mechanisms involved in AD pathology. Then, we discuss the latest therapies targeting necroptosis and ferroptosis in AD animal/cell models and human research to provide vital information for AD treatment.

Alpha-Pinene Alleviates Motor Activity in Animal Model of Huntington's Disease via Enhancing Antioxidant Capacity.

Huntington's disease (HD) is a progressive, neurodegenerative, and inherited disease. Antioxidants have been shown to be effective in slowing disease progression in animal models of HD and are under investigation in human clinical trials. α-pinene, a member of the monoterpene class, has been shown to exert antioxidant activity. Therefore, this study aimed to investigate the impact of α-pinene on animal model of HD. Thirty-two male Wistar rats received 3-Nitropropionic acid (3-NP) for induction of the disease model or treated with α-pinene + 3-NP in different groups. Motor skill, and biochemical evaluations to detect oxidant/antioxidant markers in rat cortex and striatum were performed in all groups. We found that α-pinene significantly improved 3-NP-induced changes in the body weight, rotarod activity, time taken to cross the narrow beam, and locomotor activity. Biochemical analysis revealed that α-pinene significantly decreased the 3NP-induced elevation in oxidant markers, nitrite, and malondialdehyde in both cortex and striatum. In addition, α-pinene counteracted the 3-NP-induced fall in antioxidant enzymes, including superoxide dismutase, catalase, and glutathione in the cortex and striatum. In conclusion, we found that α-pinene prevented the motor dysfunction induced by 3-NP in the animal model of Huntington's disease. Oxidants-antioxidant balance might be involved in the protective effect of α-pinene.

Non-SUMOylated alternative spliced isoforms of alpha-synuclein are more aggregation-prone and toxic.

The exon skipping of α-Synuclein (α-Syn), the main constituent of the abnormal protein aggregation in Lewy bodies of Parkinson's disease (PD), forms four isoforms. In contrast to the full length α-Syn (α-Syn 140), little is known about the splice isoforms' properties and functions. SUMOylation, a post-translational modification, regulates α-Syn function, aggregation, and degradation, but information about α-Syn isoforms and the effect of SUMOylation on them is unknown. Therefore, this study aims to characterize the SUMOylation of α-Syn isoforms and its impact on cell death and α-Syn aggregation. In a cellular model of PD induced by rotenone, cell toxicity, SUMOylation, and α-Syn aggregation with or without isoforms overexpression were evaluated. First, rotenone induced cell toxicity and α-Syn aggregation, with a significant reduction of SUMOylation and autophagy. Boosting SUMOylation prevented α-Syn aggregation, phosphorylation and recovery of autophagy. Moreover, α-Syn 140 and α-Syn 126 were SUMOylated while the other two isoforms, α-Syn 112 and 98 were not and their overexpression showed that were more toxic and induced more α-Syn aggregation. Rotenone increased their toxicity that was not affected by boosting SUMOylation. These results may indicate a role of SUMOylation in modulating α-Syn aggregation, inducing to understanding more about the behavior of α-Syn isoforms.

Protective Effect of Curcuma Extract in an Ex Vivo Model of Retinal Degeneration via Antioxidant Activity and Targeting the SUMOylation.

Retinal degeneration is the major and principal cause behind many incurable blindness diseases. Several studies indicated the neuroprotective effect of Curcuma longa in eye pathologies, specifically retinopathy. However, the molecular mechanism behind its effect has not been completely elucidated. Using an ex vivo model of retinal degeneration obtained from an ex vivo optic nerve cut (ONC), we demonstrated that Curcuma extract (Cur) exerted a neuroprotective effect. Importantly, Cur was able to modulate apoptosis and MAPK signaling pathway activation and prevent retinal ganglion cell (RGC) loss. Other well-known neuroprotective pharmacological tools, including memantine (Mem), citicoline (Cit), and ginkgolic acid (GA), were used to compare the potential mechanisms of Cur. The antioxidant activity of retinas treated with Cur following optic nerve cut was significantly higher than control, but Cur failed to change the retina glutamate content. Considering the antioxidant effect of Cur and taking advantage of our recent findings on the crosstalk between oxidative stress and post-translational protein modifiers, in particular, small ubiquitin-related modifier (SUMO), we were interested in exploring the effect of Cur on SUMOylation. We found that Cur significantly prevented the increase of protein SUMOylation, confirming our previous in vitro data indicating the cytoprotective effect of curcumin through modulating the oxidative stress and SUMO-JNK axis. Altogether, these results suggest that Curcuma protects the retina from degeneration via antioxidant activity and targets SUMOylation. Therefore, it might be considered for the combination therapy with other neuroprotective agents with different mechanisms in preclinical studies on retinal degeneration.

Syntaxin-1a and SNAP-25 expression level is increased in the blood samples of ischemic stroke patients.

The interest for the discovery of blood biomarkers for several neurological disorders, including Ischemic Stroke (IS), is growing and their identification in blood samples would be revolutionary allowing a fast and better pathology prediction or outcome and to collect information on patient recovery. The increased permeability of the blood-brain barrier, following a brain infarct, allows the detection of brain proteins in the blood flow. In this work, we analyzed the expression levels of two synaptic proteins Syntaxin (STX)-1a and Synaptosomal Associated Protein, 25 kDa (SNAP-25), in Peripheral Blood Mononuclear Cell (PBMC), serum and in Neuronal Derived Extracellular vesicles (NDEs) of IS patients, age and sex matched healthy control (HC) and younger HC (Y-HC). Interestingly, we identified STX-1a protein in the cytoplasm of PBMC and both STX-1a and SNAP-25 expression levels were significantly augmented in all IS patient's blood fractions compared to control subjects. In addition, STX-1a blood levels correlated with the IS clinical scales National Institutes of Health Stroke Scale (NIH-SS) and the modified Barthel Index (BI). These results prompted us to speculate that STX-1a and SNAP-25 hematic fluctuations depict the brain damage after an ischemic attack and that their hematic detection could represent a novel and accessible IS biomarkers.

Topical phenytoin administration accelerates the healing of acetic acid-induced colitis in rats: evaluation of transforming growth factor-beta, platelet-derived growth factor, and vascular endothelial growth factor.

Ulcerative colitis (UC), limited to the colon's innermost lining, has become a global health problem. Immunomodulatory and monoclonal antibodies are used to treat UC despite their side effects and limitations. Phenytoin is used to heal wounds owing to its effects on growth factors, collagen, and extracellular matrix synthesis. This study aimed to evaluate the effect of topical phenytoin administration in UC. Phenytoin was administered in two doses during the treatment. Eighty male Wistar rats (230-280 g) were divided randomly into ten groups of sham, control, hydrocortisone, phenytoin 1%, and 3% groups in 6- or 12-day treatment protocols. The UC model was induced by the administration of acetic acid 4% into the colon. Animals were killed on the 7th and 13th postoperative days. The main outcome measures included body weight loss, microscopic score, and ulcer index measured using specific criteria. Growth factors were measured by western blotting. Results illustrated that body weight loss was reversed in the treatment groups. Ulcer index had decreased on 6- and 12-day treatment protocols. Microscopic scores in 6-day enema treatment significantly decreased compared to the control groups. Transforming growth factor-beta (TGFß) significantly increased in a time-dependent manner and platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) significantly increased in a time- and dose-dependent manner in phenytoin 1% and 3% in the 6- and 12-day protocols. Phenytoin dose- and time-dependently reversed weight loss. In addition, histopathological parameters included microscopic scores, and the ulcer index was decreased through the induction of growth factors TGFß, PDGF, and VEGF and consequently accelerated ulcer healing.

An overview of the therapeutic effects of curcumin in reproductive disorders with a focus on the antiinflammatory and immunomodulatory activities.

Curcumin, the polyphenolic compound obtained from turmeric, has several pharmacological properties. These properties include antioxidant, antimicrobial, anti-angiogenic, anticarcinogenic, antiinflammatory, and immunomodulatory activities. Therefore, the clinical efficacy of this substance has been largely investigated for curing numerous disorders. Based on a growing body of literature, this review aimed to investigate curcumin's molecular and clinical effects on reproduction and related disorders. Curcumin in the female reproductive system attenuates folliculogenesis, promotes apoptosis of oocytes and blastocyst, and decreases embryo implantation and survival. Curcumin at <100 mg concentration shows protective effects against testicular injury. The concentration of >250 mg of curcumin exhibits immobilizing action on sperms, and at 500 mg concentration completely blocks pregnancy. Curcumin inhibits vaginal infections, attenuates the severity of the premenstrual syndrome, ameliorates inflammatory conditions in polycystic ovary syndrome, improves preeclampsia, and prevents ectopic endometrial lesions. Taken together, curcumin, because of the numerous biological activities, low level of toxicity, and lower adverse effects compared to the synthetic drugs, could be considered as a protective agent for preserving the semen quality parameters, a contraceptive, and chemotherapeutic or chemopreventive agent, as well as an appropriate agent for the treatment of female reproductive disorders.

Association between trace elements in cancerous and non-cancerous tissues with the risk of breast cancers in western Iran.

This study aimed to assess the tissue content of essential and toxic metals including lead (Pb), cadmium (Cd), arsenic (As), silver (Ag), aluminum (Al), chromium (Cr), copper (Cu), iron (Fe), selenium (Se), and zinc (Zn) in the breast cancerous tissues compared to the non-cancerous tissue. The biopsy specimens of 63 breast cancers along with 63 adjacent healthy tissues in Kurdistan Province, Iran, were collected from 2019 to 2020 and assayed using ICP-MS (Agilent 7900). The results of the Mann-Whitney test illustrated that the concentration of Pb, Cd, As, Cr, Cu, and Se were significantly elevated in cancerous tissue (p < 0.05), while Zn was the only trace element with higher levels in healthy subjects (p < 0.05). Moreover, weak to moderate correlations between elements were observed in the cancerous group including Al-Cr (r=0.60), As-Cu (r=0.52), and Cu-Se (r=0.56). In contrast, no correlation over 0.50 was found between trace elements in the non-cancerous group. Raw risk differences (RDs) accounted for a significant effect for Pb, Cd, As, Ag, Cr, Se, and Zn on the development of breast cancer. In conclusion, elevated levels of As, Cd, Cu, Pb, and Se may contribute to enhancing the risk of breast cancer.

Oral Administration of Probiotic Enterococcus durans to Ameliorate Experimental Autoimmune Encephalomyelitis in Mice.

Introduction: Probiotics, including lactobacilli, have immunomodulatory activities with promising effects on inflammatory diseases. In this study, we evaluate the effect of Enterococcus durans (Edu) and three various strains of lactobacilli (Lacto-mix), including L. rhamnosus, L. casei, and L. plantarum, to prevent Experimental Autoimmune Encephalomyelitis (EAE) features. Methods: C57BL/6 female mice were inoculated with Myelin Oigodendrocyte Glycoprotein (MOG35-55) in CFA (complete Freund's adjuvant) to induce EAE. Five groups (n=6 in each group) of animals received saline or probiotics by oral gavage with 200 µL of lactobacilli (1.5×108 CFU/mL) for 2 weeks before the immunization and during the test for one month. Results: Histopathological studies showed an increase in infiltration of inflammatory cells and destruction of the myelin membrane in the EAE group but a decrease in inflammatory cells in the probiotic-treated animals. Pro-inflammatory cytokines (Interleukin [IL]-17 and Interferon [IFN]-γ) concentration in the supernatant of the brain and spinal cord tissues showed a significant increase in the EAE compared with the normal saline group (P<0.01). While in the spinal cord tissue, there was a decrease in IL-17 in those animals treated with the Lactomix and Edu + Lacto-mix (P<0.01) and a significant decrease in IFN-γ in those animals that received Edu (P<0.05). Western blot analysis of matrix metalloproteinase-9 and myelin basic protein showed a decrease and increase in treatment and EAE groups, respectively, compared to the normal control group. Conclusion: Our data suggest that probiotic Enterococcus durans and Lacto-mix prevents EAE, but further studies are needed to clarify the exact mechanisms and their application in preclinical and clinical trials. Highlights: Dysfunction of the blood-brain barrier, migration of inflammatory cells into the Central Nervous System (CNS), and an increase in the pro-inflammatory factors, are the hallmarks in the pathogenesis of Multiple Sclerosis (MS) and Experimental Autoimmune Encephalomyelitis (EAE).The optimal effects of probiotic strains may involve the simultaneous use of more than one strain.Probiotic Enterococcus durans and Lacto-mix have a preventive effect against EAE. Plain Language Summary: Multiple Sclerosis (MS) is a myelin-degenerating autoimmune disease in the central nervous system. Experimental Autoimmune Encephalomyelitis (EAE), due to its similar clinical and pathologic features to MS, is widely used in many model studies of this disease. The microbiome refers to a genomic set of germs (bacteria, arches, fungi, and viruses), a commensal flora that lives in the intestine and niche of humans and other mammals. The microbiome affects the host's physiological system, especially the balance between health and disease. Additionally, the importance of the microbiome is evident in regulating the intestine-brain axis, or the coordination of the digestive and the central nervous system. In this regard, probiotics, including lactobacilli, have antioxidant and anti-inflammatory properties in vitro and in vivo. Probiotic strains have a wide range of health-improvement effects, and a combination of strains with specific properties provides a broader range of antimicrobial spectrum and stronger anti-inflammatory effects. Considering the critical role of probiotics in the immune system, this study aimed to investigate the possible role of Enterococcus durans alone or in combination with Lactobacillus mixture (L. rhamnosus, L. casei, and L. plantarum) on the EAE animal model of MS.