The role of myelin in neurodegeneration: implications for drug targets and neuroprotection strategies

Myelination of axons in the central nervous system offers numerous advantages, including decreased energy expenditure for signal transmission and enhanced signal speed. The myelin sheaths surrounding an axon consist of a multi-layered membrane that is formed by oligodendrocytes, while specific glycoproteins and lipids play various roles in this formation process. As beneficial as myelin can be, its dysregulation and degeneration can prove detrimental. Inflammation, oxidative stress, and changes in cellular metabolism and the extracellular matrix can lead to demyelination of these axons. These factors are hallmark characteristics of certain demyelinating diseases including multiple sclerosis. The effects of demyelination are also implicated in primary degeneration in diseases such as glaucoma and Alzheimer's disease, as well as in processes of secondary degeneration. This reveals a relationship between myelin and secondary processes of neurodegeneration, including resultant degeneration following traumatic injury and transsynaptic degeneration. The role of myelin in primary and secondary degeneration is also of interest in the exploration of strategies and targets for remyelination, including the use of anti-inflammatory molecules or nanoparticles to deliver drugs. Although the use of these methods in animal models of diseases have shown to be effective in promoting remyelination, very few clinical trials in patients have met primary end points. This may be due to shortcomings or considerations that are not met while designing a clinical trial that targets remyelination. Potential solutions include diversifying disease targets and requiring concomitant interventions to promote rehabilitation.

Glial Cell Activation and Immune Responses in Glaucoma: A Systematic Review of Human Postmortem Studies of the Retina and Optic Nerve

Although researched extensively the understanding regarding mechanisms underlying glaucoma pathogenesis remains limited. Further, the exact mechanism behind neuronal death remains elusive. The role of neuroinflammation in retinal ganglion cell (RGC) death has been prominently theorised. This review provides a comprehensive summary of neuroinflammatory responses in glaucoma. A systematic search of Medline and Embase for articles published up to 8th March 2023 yielded 32 studies using post-mortem tissues from glaucoma patients. The raw data were extracted from tables and text to calculate the standardized mean differences (SMDs). These studies utilized post-mortem tissues from glaucoma patients, totalling 490 samples, compared with 380 control samples. Among the included studies, 27 reported glial cell activation based on changes to cellular morphology and molecular staining. Molecular changes were predominantly attributed to astrocytes (62.5%) and microglia (15.6%), with some involvement of Muller cells. These glial cell changes included amoeboid microglial cells with increased CD45 or HLA-DR intensity and hypertrophied astrocytes with increased glial fibrillary acidic protein labelling. Further, changes to extracellular matrix proteins like collagen, galectin, and tenascin-C suggested glial cells' influence on structural changes in the optic nerve head. The activation of DAMPs-driven immune response and the classical complement cascade was reported and found to be associated with activated glial cells in glaucomatous tissue. Increased pro-inflammatory markers such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were also linked to glial cells. Glial cell activation was also associated with mitochondrial, vascular, metabolic and antioxidant component disruptions. Association of the activated glial cells with pro-inflammatory responses, dysregulation of homeostatic components and antigen presentation indicates that glial cell responses influence glaucoma progression. However, the exact mechanism triggering these responses and underlying interactions remains unexplored. This necessitates further research using human samples for an increased understanding of the precise role of neuroinflammation in glaucoma progression.

Semen proteomics reveals alterations in fertility-related proteins post-recovery from COVID-19

Introduction: Changes to sperm quality and decline in reproductive function have been reported in COVID-19-recovered males. Further, the emergence of SARS-CoV-2 variants has caused the resurgences of COVID-19 cases globally during the last 2 years. These variants show increased infectivity and transmission along with immune escape mechanisms, which threaten the already burdened healthcare system. However, whether COVID-19 variants induce an effect on the male reproductive system even after recovery remains elusive. Methods: We used mass-spectrometry-based proteomics approaches to understand the post-COVID-19 effect on reproductive health in men using semen samples post-recovery from COVID-19. The samples were collected between late 2020 (1st wave, n = 20), and early-to-mid 2021 (2nd wave, n = 21); control samples were included (n = 10). During the 1st wave alpha variant was prevalent in India, whereas the delta variant dominated the second wave. Results: On comparing the COVID-19-recovered patients from the two waves with control samples, using one-way ANOVA, we identified 69 significantly dysregulated proteins among the three groups. Indeed, this was also reflected by the changes in sperm count, morphology, and motility of the COVID-19- recovered patients. In addition, the pathway enrichment analysis showed that the regulated exocytosis, neutrophil degranulation, antibacterial immune response, spermatogenesis, spermatid development, regulation of extracellular matrix organization, regulation of peptidase activity, and regulations of calcium ion transport were significantly dysregulated. These pathways directly or indirectly affect sperm parameters and function. Our study provides a comprehensive landscape of expression trends of semen proteins related to male fertility in men recovering from COVID-19. Discussion: Our study suggests that the effect of COVID-19 on the male reproductive system persists even after recovery from COVID-19. In addition, these post-COVID-19 complications persist irrespective of the prevalent variants or vaccination status.

Humoral Immune Response Profile of COVID-19 Reveals Severity and Variant-Specific Epitopes: Lessons from SARS-CoV-2 Peptide Microarray

The amaranthine scale of the COVID-19 pandemic and unpredictable disease severity is of grave concern. Serological diagnostic aids are an excellent choice for clinicians for rapid and easy prognosis of the disease. To this end, we studied the humoral immune response to SARS-CoV-2 infection to map immunogenic regions in the SARS-CoV-2 proteome at amino acid resolution using a high-density SARS-CoV-2 proteome peptide microarray. The microarray has 4932 overlapping peptides printed in duplicates spanning the entire SARS-CoV-2 proteome. We found 204 and 676 immunogenic peptides against IgA and IgG, corresponding to 137 and 412 IgA and IgG epitopes, respectively. Of these, 6 and 307 epitopes could discriminate between disease severity. The emergence of variants has added to the complexity of the disease. Using the mutation panel available, we could detect 5 and 10 immunogenic peptides against IgA and IgG with mutations belonging to SAR-CoV-2 variants. The study revealed severity-based epitopes that could be presented as potential prognostic serological markers. Further, the mutant epitope immunogenicity could indicate the putative use of these markers for diagnosing variants responsible for the infection.

Proteomic Investigation of COVID-19 Severity During the Tsunamic Second Wave in Mumbai

Maharashtra was severely affected during the noxious second wave of COVID-19, with the highest number of cases recorded across India. The emergence of new symptoms and dysregulation of multiple organs resulted in high disease severity during the second wave which led to increased difficulties in understanding the molecular mechanisms behind the disease pathology. Exploring the underlying factors can help to relieve the burden on the medical communities to some extent by prioritizing the patients and, at the same time, opening avenues for improved treatments. In the current study, we have performed a mass-spectrometry-based proteomic analysis to investigate the disease pathology using nasopharyngeal swab samples collected from the COVID-19 patients in the Mumbai region of Maharashtra over the period of March-June 2021, the peak of the second wave. A total of 59 patients, including 32 non-severe and 27 severe cases, were considered for this proteomic study. We identified 23 differentially regulated proteins in severe patients as a host response to infection. In addition to the previously identified innate mechanisms of neutrophil and platelet degranulation, this study revealed significant alterations of anti-microbial peptide pathways in severe conditions, illustrating its role in the severity of the infectious strain of COVID-19 during the second wave. Furthermore, myeloperoxidase, cathepsin G, and profilin-1 were identified as potential therapeutic targets of the FDA-approved drugs dabrafenib, ZINC4097343, and ritonavir. This study has enlightened the role of the anti-microbial peptide pathway associated with the second wave in India and proposed its importance in potential therapeutics for COVID-19.

A Multi-omics Longitudinal Study Reveals Alteration of the Leukocyte Activation Pathway in COVID-19 Patients

Severe coronavirus disease 2019 (COVID-19) infection may lead to lung injury, multi-organ failure, and eventually death. Cytokine storm due to excess cytokine production has been associated with fatality in severe infections. However, the specific molecular signatures associated with the elevated immune response are yet to be elucidated. We performed a mass-spectrometry-based proteomic and metabolomic analysis of COVID-19 plasma samples collected at two time points. Using Orbitrap Fusion LC-MS/MS-based label-free proteomic analysis, we identified around 10 significant proteins, 32 significant peptides, and 5 metabolites that were dysregulated at the severe time points. Few of these proteins identified by quantitative proteomics were validated using the multiple reaction monitoring (MRM) assay. Integrated pathway analysis using distinct proteomic and metabolomic signatures revealed alterations in complement and coagulation cascade, platelet aggregation, myeloid leukocyte activation pathway, and arginine metabolism. Further, we highlight the role of leukocyte activation and arginine metabolism in COVID-19 pathogenesis and targeting these pathways for COVID-19 therapeutics.

Rapid Classification of COVID-19 Severity by ATR-FTIR Spectroscopy of Plasma Samples

The coronavirus disease 2019 (COVID-19) pandemic continues to ravage the world, with many hospitals overwhelmed by the large number of patients presenting during major outbreaks. A rapid triage for COVID-19 patient requiring hospitalization and intensive care is urgently needed. Age and comorbidities have been associated with a higher risk of severe COVID-19 but are not sufficient to triage patients. Here, we investigated the potential of attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy as a rapid blood test for classification of COVID-19 disease severity using a cohort of 160 COVID-19 patients. A simple plasma processing and ATR-FTIR data acquisition procedure was established using 75% ethanol for viral inactivation. Next, partial least-squares-discriminant analysis (PLS-DA) models were developed and tested using data from 130 and 30 patients, respectively. Addition of the ATR-FTIR spectra to the clinical parameters (age, sex, diabetes mellitus, and hypertension) increased the area under the ROC curve (C-statistics) for both the training and test data sets, from 69.3% (95% CI 59.8-78.9%) to 85.7% (78.6-92.8%) and 77.8% (61.3-94.4%) to 85.1% (71.3-98.8%), respectively. The independent test set achieved 69.2% specificity (42.4-87.3%) and 94.1% sensitivity (73.0-99.0%). Diabetes mellitus was the strongest predictor in the model, followed by FTIR regions 1020-1090 and 1588-1592 cm-1. In summary, this study demonstrates the potential of ATR-FTIR spectroscopy as a rapid, low-cost COVID-19 severity triage tool to facilitate COVID-19 patient management during an outbreak.

Mumbai mayhem of COVID-19 pandemic reveals important factors that influence susceptibility to infection

BACKGROUND

COVID-19 severity is disproportionately high in the elderly and people with comorbidities. However, other factors that predispose individuals to increased chances of infection are unclear.

METHODS

Data from 18,600 people screened for COVID-19 in Mumbai during the outbreak's initial phase, March 7 to June 30, 2020, were used to assess risk factors associated with COVID-19 using the odds ratio analysis.

FINDINGS

Males aged ≥60 years having both diabetes and hypertension were at the highest risk of COVID-19 infection (M vs. F OR=2.5, 95% CI=1.34-4.67, p = 0.0049). People having both diabetes and hypertension in ≥20 years (OR=4.11, 95% CI=3.26-5.20, p <0.0001), diabetes and hypertension independently in 20-39 (OR=4.13, 95% CI=2.22-7.70, p <0.0001, OR=4.32, 95% CI=2.10-8.88, p = 0.0001) and ≥60 years (OR=2.69, 95% CI=1.87-3.87, p <0.0001, OR=2.03, 95% CI=1.46-2.82, p <0.0001), chronic renal disease in 20-39 years (OR=5.38, 95% CI=1.91-15.09, p = 0.0007) age groups had significantly higher risk of COVID-19 infection than those without comorbidity. Quarantined people had significantly lower positive odds (OR=0.59, 95% CI=0.53-0.66, p <0.001) than non-quarantined people.

INTERPRETATION

Our research indicates that the risk of getting COVID-19 disease is not equal. When considering sex, age, and comorbidity together, we found that males aged ≥60 years and having both diabetes and hypertension had a significantly high risk of COVID-19 infection. Therefore, remedial measures such as vaccination programs should be prioritized for at-risk individuals.

FUNDING

SERB, India: SB/S1/COVID-2/2020 and Seed grant RD/0520-IRCCHC0-006 from IRCC, IIT Bombay.

Proteomics and Machine Learning Approaches Reveal a Set of Prognostic Markers for COVID-19 Severity With Drug Repurposing Potential

The pestilential pathogen SARS-CoV-2 has led to a seemingly ceaseless pandemic of COVID-19. The healthcare sector is under a tremendous burden, thus necessitating the prognosis of COVID-19 severity. This in-depth study of plasma proteome alteration provides insights into the host physiological response towards the infection and also reveals the potential prognostic markers of the disease. Using label-free quantitative proteomics, we performed deep plasma proteome analysis in a cohort of 71 patients (20 COVID-19 negative, 18 COVID-19 non-severe, and 33 severe) to understand the disease dynamics. Of the 1200 proteins detected in the patient plasma, 38 proteins were identified to be differentially expressed between non-severe and severe groups. The altered plasma proteome revealed significant dysregulation in the pathways related to peptidase activity, regulated exocytosis, blood coagulation, complement activation, leukocyte activation involved in immune response, and response to glucocorticoid biological processes in severe cases of SARS-CoV-2 infection. Furthermore, we employed supervised machine learning (ML) approaches using a linear support vector machine model to identify the classifiers of patients with non-severe and severe COVID-19. The model used a selected panel of 20 proteins and classified the samples based on the severity with a classification accuracy of 0.84. Putative biomarkers such as angiotensinogen and SERPING1 and ML-derived classifiers including the apolipoprotein B, SERPINA3, and fibrinogen gamma chain were validated by targeted mass spectrometry-based multiple reaction monitoring (MRM) assays. We also employed an in silico screening approach against the identified target proteins for the therapeutic management of COVID-19. We shortlisted two FDA-approved drugs, namely, selinexor and ponatinib, which showed the potential of being repurposed for COVID-19 therapeutics. Overall, this is the first most comprehensive plasma proteome investigation of COVID-19 patients from the Indian population, and provides a set of potential biomarkers for the disease severity progression and targets for therapeutic interventions.

Proteomic investigation reveals dominant alterations of neutrophil degranulation and mRNA translation pathways in patients with COVID-19

The altered molecular proteins and pathways in response to COVID-19 infection are still unclear. Here, we performed a comprehensive proteomics-based investigation of nasopharyngeal swab samples from patients with COVID-19 to study the host response by employing simple extraction strategies. Few of the host proteins such as interleukin-6, L-lactate dehydrogenase, C-reactive protein, Ferritin, and aspartate aminotransferase were found to be upregulated only in COVID-19-positive patients using targeted multiple reaction monitoring studies. The most important pathways identified by enrichment analysis were neutrophil degranulation, interleukin-12 signaling pathways, and mRNA translation of proteins thus providing the detailed investigation of host response in COVID-19 infection. Thus, we conclude that mass spectrometry-detected host proteins have a potential for disease severity progression; however, suitable validation strategies should be deployed for the clinical translation. Furthermore, the in silico docking of potential drugs with host proteins involved in the interleukin-12 signaling pathway might aid in COVID-19 therapeutic interventions.

Coexisting prostate adenocarcinoma with multiple myeloma: A rare case report

We report a rare case of an 83-year-old male with synchronous occurrence of prostate adenocarcinoma and multiple myeloma. He presented with lower back pain and incontinence of urine for the past 6 months. Routine hematological and biochemical investigations were performed which pointed toward prostate adenocarcinoma. Transrectal ultrasonography and magnetic resonance imaging showed prostatomegaly along with osteolytic lesions in the skull and vertebrae. Prostate biopsy was performed and adenocarcinoma was confirmed. To rule out metastatic deposits in the bone and to rule out bone marrow infiltration, bone marrow aspiration and biopsy of the patient was done, and unexpectedly, it showed multiple myeloma. The association between these two disorders is poorly understood, but some studies show that bone marrow microenvironment plays an important role.