Triangle of cytokine storm, central nervous system involvement, and viral infection in COVID-19: the role of sFasL and neuropilin-1

Matrix metalloproteinase/Fas ligand (MMP/FasL) interaction dynamics in COVID-19: An in silico study and neuroimmune perspective

Background

The initiator of cytokine storm in Coronavirus disease (COVID-19) is still unknown. We recently suggested a complex interaction of matrix metalloproteinases (MMPs), Fas ligand (FasL), and viral entry factors could be responsible for the cytokine outrage In COVID-19. We explored the molecular dynamics of FasL/MMP7-9 in COVID-19 conditions in silico and provide neuroimmune insights for future.

Methods

We enrolled and analyzed a clinical cohort of COVID-19 patients, and recorded their blood Na + levels and temperature at admission. A blood-like molecular dynamics simulation (MDS) box was then built. Four conditions were studied; MMP7/FasL (healthy), MMP7/FasL (COVID-19), MMP9-FasL (healthy), and MMP9/FasL (COVID-19). MDS was performed by GROningen MAchine for Chemical Simulation (GROMACS). We analyzed bonds, short-range energies, and free binding energies to draw conclusions on the interaction of MMP7/MMP9 and FasL to gain insights into COVID-19 immunopathology. Genevestigator was used study RNA-seq/microarray expression data of MMPs in the cells of immune and nervous systems. Finally, epitopes of MMP/FasL complexes were identified as drug targets by machine learning (ML) tools.

Results

MMP7-FasL (Healthy), MMP7-FasL (COVID-19), MMP9-FasL (Healthy), and MMP9-FasL (COVID-19) systems showed 0, 1, 4, and 2 salt bridges, indicating MMP9 had more salt bridges. Moreover, in both COVID-19 and normal conditions, the number of interacting residues and surface area was higher for MMP9 compared to MMP7 group. The COVID-19 MMP9-FasL group had more H-bonds compared to MMP7-FasL group (12 vs. 7). 15 epitopes for FasL-MMP9 and 10 epitopes for FasL-MMP7 were detected. Extended MD simulation for 100 ns confirmed stronger binding of MMP9 based on Molecular Mechanics Generalized Borne Surface analysis (MM-GBSA) and Coul and Leonard-Jones (LJ) short-range energies.

Conclusions

MMP9 interacts stronger than MMP7 with FasL, however, both molecules maintained strong interaction through the MDS. We suggested epitopes for MMP-FasL complexes as valuable therapeutic targets in COVID-19. These data could be utilized in future immune drug and protein design and repurposing efforts.

Empagliflozin treatment of cardiotoxicity: A comprehensive review of clinical, immunobiological, neuroimmune, and therapeutic implications

Cancer and cardiovascular disorders are known as the two main leading causes of mortality worldwide. Cardiotoxicity is a critical and common adverse effect of cancer-related chemotherapy. Chemotherapy-induced cardiotoxicity has been associated with various cancer treatments, such as anthracyclines, immune checkpoint inhibitors, and kinase inhibitors. Different methods have been reported for the management of chemotherapy-induced cardiotoxicity. In this regard, sodium-glucose cotransporter-2 inhibitors (SGLT2i), a class of antidiabetic agents, have recently been applied to manage heart failure patients. Further, SGLT2i drugs such as EMPA exert protective cardiac and systemic effects. Moreover, it can reduce inflammation through the mediation of major inflammatory components, such as Nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasomes, Adenosine 5'-monophosphate-activated protein kinase (AMPK), and c-Jun N-terminal kinase (JNK) pathways, Signal transducer and activator of transcription (STAT), and overall decreasing transcription of proinflammatory cytokines. The clinical outcome of EMPA administration is related to improving cardiovascular risk factors, including body weight, lipid profile, blood pressure, and arterial stiffness. Intriguingly, SGLT2 suppressors can regulate microglia-driven hyperinflammation affecting neurological and cardiovascular disorders. In this review, we discuss the protective effects of EMPA in chemotherapy-induced cardiotoxicity from molecular, immunological, and neuroimmunological aspects to preclinical and clinical outcomes.

Mortality in ICU COVID-19 Patients Is Associated with Neutrophil-to-Lymphocyte Ratio (NLR): Utility of NLR as a Promising Immunohematological Marker

Background

Achieving a suitable medical laboratory index is very important for the prediction of clinical outcome of COVID-19 patients hospitalized to the intensive care unit (ICU). The correlation between neutrophil-to-lymphocyte ratio (NLR) and unfavorable outcome of COVID-19 patients hospitalized to ICU was the aim of this study.

Methods

We evaluated a cross-sectional study of 312 COVID-19 patients who were hospitalized to the ICU (confirmed by PCR and CT-Scan), in Babol city, Mazandaran province. WBC, RBC, lymphocyte, neutrophil, monocyte, platelet count, NLR, C-reactive protein (CRP), ESR, MCV, MHC, and other factors were evaluated.

Results

Our findings indicated that all patients aged 56 to 69 years with COVID-19 had a significant difference (P < 0.05) in neu, lymph, PLT count, NLR, ESR, Hb, and CRP. Also, NLR was significantly (P < 0.05) correlated with the death or discharge of the ICU hospitalized patients. The cut-off of NLR was 7.02 and the mean of NLR was 11.3 ± 10.93 and 5.8 ± 7.45 in death and discharge COVID-19 patients hospitalized to ICU, respectively. ROC curve indicated that, for NLR, the area under curve was 0.76.

Conclusions

Our findings showed that NLR can be utilized as a clinical laboratory predictive parameter for mortality of COVID-19 patients admitted to ICU.

Is neuropilin-1 the neuroimmune initiator of multi-system hyperinflammation in COVID-19?

A major immunopathological feature of Coronavirus disease-2019 (COVID-19) is excessive inflammation in the form of "cytokine storm". The storm is characterized by injurious levels of cytokines which form a complicated network damaging different organs, including the lungs and the brain. The main starter of "cytokine network" hyperactivation in COVID-19 has not been discovered yet. Neuropilins (NRPs) are transmembrane proteins that act as neuronal guidance and angiogenesis modulators. The crucial function of NRPs in forming the nervous and vascular systems has been well-studied. NRP1 and NRP2 are the two identified homologs of NRP. NRP1 has been shown as a viral entry pathway for SARS-CoV2, which facilitates neuroinvasion by the virus within the central or peripheral nervous systems. These molecules directly interact with various COVID-19-related molecules, such as specific regions of the spike protein (major immune element of SARS-CoV2), vascular endothelial growth factor (VEGF) receptors, VEGFR1/2, and ANGPTL4 (regulator of vessel permeability and integrity). NRPs mainly play a role in hyperinflammatory injury of the CNS and lungs, and also the liver, kidney, pancreas, and heart in COVID-19 patients. New findings have suggested NRPs good candidates for pharmacotherapy of COVID-19. However, therapeutic targeting of NRP1 in COVID-19 is still in the preclinical phase. This review presents the implications of NRP1 in multi-organ inflammation-induced injury by SARS-CoV2 and provides insights for NRP1-targeting treatments for COVID-19 patients.

Neurological adverse effects of chimeric antigen receptor T-cell therapy

INTRODUCTION

Chimeric antigen receptor (CAR) T-cell is among the most prevalent approaches that act by directing T-cells toward cancer; however, they need to be optimized to minimize side effects and maximize efficacy before being used as standard treatment for malignancies. Neurotoxicity associated with CAR T-cell therapy has been well-documented in recent works.

AREAS COVERED

In this regard, two established syndromes exist. Immune effector cell-associated neurotoxicity syndrome (ICANS), previously called cytokine release encephalopathy syndrome (CRES), is a neuropsychiatric condition which can occur after therapy by immune effector cells (IEC) and T-lymphocytes utilizing treatments. Another syndrome is cytokine release syndrome (CRS), which may overlap with ICANS.

EXPERT OPINION

ICANS clinical manifestations include cerebral edema, mild lethargy, aphasia, and seizures. Notably, ICANS is associated with changes to EEG and neuroradiological findings. Therefore, it is necessary to make a timely and accurate diagnosis of neurological complications of CAR T-cells by clinical presentations, neuroimaging, and EEG. Since neurological events by different CAR T-cell products are heterogeneous, guides should be developed according to each product. Here, we provide an updated review of general information on CAR T-cell therapies and applications, neurological syndromes associated with their use, and risk factors contributing to ICANS.

Deep brain stimulation (DBS) as a therapeutic approach in gait disorders: What does it bring to the table?

Gait deficits are found in various degenerative central nervous system conditions, and are particularly a hallmark of Parkinson's disease (PD). While there is no cure for such neurodegenerative disorders, Levodopa is considered as the standard medication in PD patients. Often times, the therapy of severe PD consists of deep brain stimulation (DBS) of the subthalamic nucleus. Earlier research exploring the effect of gait have reported contradictory results or insufficient efficacy. A change in gait includes various parameters, such as step length, cadence, Double-stance phase duration which may be positively affected by DBS. DBS could also be effective in correcting the levodopa-induced postural sway abnormalities. Moreover, during normal walking, interaction among the subthalamic nucleus and cortex -essential regions which exert a role in locomotion- are coupled. However, during the freezing of gait, the activity is desynchronized. The mechanisms underlying DBS-induced neurobehavioral improvements in such scenarios requires further study. The present review discusses DBS in the context of gait, the benefits associated with DBS compared to standard pharmacotherapy options, and provides insights into future research.

Host microRNA interactions with the SARS-CoV-2 viral genome 3'-untranslated region

The 2019 pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has marked the spread of a novel human coronavirus. While the viral life cycle is well understood, most of the interactions at the virus-host interface remain elusive. Furthermore, the molecular mechanisms behind disease severity and immune evasion are still largely unknown. Conserved elements of the viral genome such as secondary structures within the 5'- and 3'-untranslated regions (UTRs) serve as attractive targets of interest and could prove crucial in furthering our understanding of virus-host interactions. It has been proposed that microRNA (miR) interactions with viral components could be used by both the virus and host for their own benefit. Analysis of the SARS-CoV-2 viral genome 3'-UTR has revealed the potential for host cellular miR binding sites, providing sites for specific interactions with the virus. In this study, we demonstrate that the SARS-CoV-2 genome 3'-UTR binds the host cellular miRNAs miR-760-3p, miR-34a-5p, and miR-34b-5p, which have been shown to influence translation of interleukin-6 (IL-6), the IL-6 receptor (IL-6R), as well as progranulin (PGRN), respectively, proteins that have roles in the host immune response and inflammatory pathways. Furthermore, recent work suggests the potential of miR-34a-5p and miR-34b-5p to target and inhibit translation of viral proteins. Native gel electrophoresis and steady-state fluorescence spectroscopy were utilized to characterize the binding of these miRs to their predicted sites within the SARS-CoV-2 genome 3'-UTR. Additionally, we investigated 2'-fluoro-D-arabinonucleic acid (FANA) analogs of these miRNAs as competitive binding inhibitors for these miR binding interactions. The mechanisms detailed in this study have the potential to drive the development of antiviral treatments for SARS-CoV-2 infection, and provide a potential molecular basis for cytokine release syndrome and immune evasion which could implicate the host-virus interface.

Exogenous Players in Mitochondria-Related CNS Disorders: Viral Pathogens and Unbalanced Microbiota in the Gut-Brain Axis

Billions of years of co-evolution has made mitochondria central to the eukaryotic cell and organism life playing the role of cellular power plants, as indeed they are involved in most, if not all, important regulatory pathways. Neurological disorders depending on impaired mitochondrial function or homeostasis can be caused by the misregulation of "endogenous players", such as nuclear or cytoplasmic regulators, which have been treated elsewhere. In this review, we focus on how exogenous agents, i.e., viral pathogens, or unbalanced microbiota in the gut-brain axis can also endanger mitochondrial dynamics in the central nervous system (CNS). Neurotropic viruses such as Herpes, Rabies, West-Nile, and Polioviruses seem to hijack neuronal transport networks, commandeering the proteins that mitochondria typically use to move along neurites. However, several neurological complications are also associated to infections by pandemic viruses, such as Influenza A virus and SARS-CoV-2 coronavirus, representing a relevant risk associated to seasonal flu, coronavirus disease-19 (COVID-19) and "Long-COVID". Emerging evidence is depicting the gut microbiota as a source of signals, transmitted via sensory neurons innervating the gut, able to influence brain structure and function, including cognitive functions. Therefore, the direct connection between intestinal microbiota and mitochondrial functions might concur with the onset, progression, and severity of CNS diseases.

Impaired VEGF-A-Mediated Neurovascular Crosstalk Induced by SARS-CoV-2 Spike Protein: A Potential Hypothesis Explaining Long COVID-19 Symptoms and COVID-19 Vaccine Side Effects?

Long coronavirus disease-19 (COVID-19) is a newly discovered syndrome characterized by multiple organ manifestations that persist for weeks to months, following the recovery from acute disease. Occasionally, neurological and cardiovascular side effects mimicking long COVID-19 have been reported in recipients of COVID-19 vaccines. Hypothetically, the clinical similarity could be due to a shared pathogenic role of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike (S) protein produced by the virus or used for immunization. The S protein can bind to neuropilin (NRP)-1, which normally functions as a coreceptor for the vascular endothelial growth factor (VEGF)-A. By antagonizing the docking of VEGF-A to NRP-1, the S protein could disrupt physiological pathways involved in angiogenesis and nociception. One consequence could be the increase in unbound forms of VEGF-A that could bind to other receptors. SARS-CoV-2-infected individuals may exhibit increased plasma levels of VEGF-A during both acute illness and convalescence, which could be responsible for diffuse microvascular and neurological damage. A few studies suggest that serum VEGF-A may also be a potential biomarker for long COVID-19, whereas evidence for COVID-19 vaccines is lacking and merits further investigation.

Mechanisms of COVID-19-induced cerebellitis

The COVID-19 pandemic caused by SARS-CoV2 has raised several important health concerns, not least increased mortality and morbidity. SARS-CoV2 can infect the central nervous system via hematogenous or transneuronal routes, acting through different receptors including ACE2, DPP4, and neuropilin 1 and cause several issues, including the focus here, cerebellitis. The cerebellum is an essential part of the CNS located adjacent to the brainstem with a complex micro and macroscopic structure. The cerebellum plays several physiological roles, such as coordination, cognition, and executive functioning. Damage to the cerebellum can lead to incoordination and ataxia. In our narrative review, we searched different databases from 2021 to 2022 with the keywords cerebellum and COVID-19; 247 studies were identified and reviewed, focusing on clinical studies and excluding non-clinical studies; 56 studies were finally included for analysis. SARS-CoV2 infection of the cerebellum can be seen to be assessed through many methods such as MRI, PET, CT, postmortem studies, and histological findings. These methodological studies have demonstrated that cerebellar infection with COVID-19 can bring about several sequelae: thrombosis, microbleed, hemorrhage, stroke, autoantibody production, ataxia, and widespread inflammation in the cerebellum. Such central effects are likely to exacerbate the known multiorgan effects of SARS-CoV2 and should also be considered as part of disease prognosis.

Recombinant human plasma gelsolin reverses increased permeability of the blood-brain barrier induced by the spike protein of the SARS-CoV-2 virus

BACKGROUND

Plasma gelsolin (pGSN) is an important part of the blood actin buffer that prevents negative consequences of possible F-actin deposition in the microcirculation and has various functions during host immune response. Recent reports reveal that severe COVID-19 correlates with reduced levels of pGSN. Therefore, using an in vitro system, we investigated whether pGSN could attenuate increased permeability of the blood-brain barrier (BBB) during its exposure to the portion of the SARS-CoV-2 spike protein containing the receptor binding domain (S1 subunit).

MATERIALS AND METHODS

Two- and three-dimensional models of the human BBB were constructed using the human cerebral microvascular endothelial cell line hCMEC/D3 and exposed to physiologically relevant shear stress to mimic perfusion in the central nervous system (CNS). Trans-endothelial electrical resistance (TEER) as well as immunostaining and Western blotting of tight junction (TJ) proteins assessed barrier integrity in the presence of the SARS-CoV-2 spike protein and pGSN. The IncuCyte Live Imaging system evaluated the motility of the endothelial cells. Magnetic bead-based ELISA was used to determine cytokine secretion. Additionally, quantitative real-time PCR (qRT-PCR) revealed gene expression of proteins from signaling pathways that are associated with the immune response.

RESULTS

pGSN reversed S1-induced BBB permeability in both 2D and 3D BBB models in the presence of shear stress. BBB models exposed to pGSN also exhibited attenuated pro-inflammatory signaling pathways (PI3K, AKT, MAPK, NF-κB), reduced cytokine secretion (IL-6, IL-8, TNF-α), and increased expression of proteins that form intercellular TJ (ZO-1, occludin, claudin-5).

CONCLUSION

Due to its anti-inflammatory and protective effects on the brain endothelium, pGSN has the potential to be an alternative therapeutic target for patients with severe SARS-CoV-2 infection, especially those suffering neurological complications of COVID-19.

Microglia dynamics in aging-related neurobehavioral and neuroinflammatory diseases

Microglia represent the first line of immune feedback in the brain. Beyond immune surveillance, they are essential for maintaining brain homeostasis. Recent research has revealed the microglial cells' spatiotemporal heterogeneity based on their local and time-based functions in brain trauma or disease when homeostasis is disrupted. Distinct "microglial signatures" have been recorded in physiological states and brain injuries, with discrete or sometimes overlapping pro- and anti-inflammatory functions. Microglia are involved in the neurological repair processes, such as neurovascular unit restoration and synaptic plasticity, and manage the extent of the damage due to their phenotype switching. The versatility of cellular phenotypes beyond the classical M1/M2 classification, as well as the double-edge actions of microglia in neurodegeneration, indicate the need for further exploration of microglial cell dynamics and their contribution to neurodegenerative processes. This review discusses the homeostatic functions of different microglial subsets focusing on neuropathological conditions. Also, we address the feasibility of targeting microglia as a therapeutic strategy in neurodegenerative diseases.

In silico design of a TLR4-mediating multiepitope chimeric vaccine against amyotrophic lateral sclerosis via advanced immunoinformatics

Amyotrophic lateral sclerosis (ALS) is the most prevalent motor neuron disorder worldwide. In ALS, progressing disease can result from misfolding and aggregation of superoxide dismutase-1 (SOD1) or TAR DNA-binding protein 43 kDa (TDP43). An efficient immunotherapy for ALS should spare intact SOD1 while eliminating its dysfunctional variant. We utilized advanced immunoinformatics to suggest a potential vaccine candidate against ALS by proposing a model of dynamic TLR4 mediation and induction of a specific Th2-biased shift against mutant SOD1, TDP43, and TRAF6, a protein that specifically interacts with dysfunctional SOD1. SOD1, TDP43, and TRAF6 were retrieved in FASTA. Immune Epitopes Database and CTLpred suggested T/B-cell epitopes from disease-specific regions of selected antigens. A TLR4-mediating adjuvant, RS01, was used. Sequences were assembled via suitable linkers. Tertiary structure of the protein was calculated. Refined protein structure and physicochemical features of the 3D structure were verified in silico. Differential immune induction was assessed via C-ImmSim. GROningen MAchine for Chemical Simulation was used to assess evolution of the docked vaccine-TLR4 complex in blood. Our protein showed high structural quality and was nonallergenic and immune inducing. Also, the vaccine-TLR4 complex stability was verified by RMSD, RMSF, gyration, and visual analyses of the molecular dynamic trajectory. Contact residues in the vaccine-TLR4 complex showed favorable binding energies. Immune stimulation analyses of the proposed candidate demonstrated a sustained memory cell response and a strong adaptive immune reaction. We proposed a potential vaccine candidate against ALS and verified its physicochemical and immune inducing features. Future studies should assess this vaccine in animal studies.

Utilizing Immunoinformatics to Target Brain Tumors; An Aid to Current Neurosurgical Practice

Context: Despite major advancements in the field, the current neurosurgical practice requires an interdisciplinary approach. It is known that surgical practice and other cancer-eliminating treatments can be combined for optimal results. However, recent attempts have failed to address many debilitating conditions, indicating an emergent need for novel interdisciplinary therapeutic approaches. Evidence Acquisition: We searched PubMed and Google Scholar for the keywords “immunoinformatics,” “in silico,” “neurology,” and “neurosurgery.” Without time restriction. Results: The immune system is versatile because it is involved in physiological brain function and affects the course of central nervous system (CNS) disease and infection. A novel approach combines neurosurgery and immunoinformatics for optimal results. For instance, brain tumors, such as glioblastoma multiforme (GBM), are still associated with a severely reduced survival of patients, and resection of tumors may provide little help. In silico approaches could help to identify molecular pathways and design immunotherapies for such conditions at a significantly increased speed compared to traditional vaccinology approaches. Conclusions: The neurosurgical practice could be affected by different infectious organisms. These organisms can be targeted by in silico vaccinology techniques. Here, we provide a brief overview of bioinformatics/immunoinformatics and discuss the possible role of immunoinformatics in neurosurgery. In light of the current Coronavirus disease-2019 (COVID-19) epidemic, projections for future studies are also included.

The Efficacy of Methylprednisolone in Clinical Manifestations, Inflammatory Biomarkers, and Antioxidant Changes in the COVID-19 Patients

Background: The application of methylprednisolone in ARDS patients has led to a sustained reduction in inflammatory plasma cytokines and chemokines and has recently been used in the treatment of patients with SARS-CoV-2 infection. Objectives: In this study, the effect of methylprednisolone on clinical symptoms and antioxidant changes of patients with COVID-19 has been investigated. Methods: In the present study, patients with moderate to severe COVID-19 who required hospitalization were entered into the study phase. Then, in addition to standard treatment, patients received methylprednisolone at a dose of 250 mg intravenously over three days. Necessary evaluations include analysis of arterial blood gases, pulse oximetry, monitoring of patient clinical signs, examination of inflammatory biomarkers, and also receiving 10 cc of peripheral blood samples to check for antioxidant changes, at the beginning of the study, after 24 hours, and 72 hours after receiving methylprednisolone was on the agenda. Results: Changes in fever, superoxide dismutase (SOD, Glutathione-S-Transferase (GST, the ferric reducing ability of plasma (FRAP, malondialdehyde (MDA, Nitric oxide, Ferritin, and TNF-α before treatment and 72 hours after treatment were significantly different between the two stages (P < 0.05). Conclusions: The use of methylprednisolone improves the balance of antioxidants and immunological factors in patients with COVID-19 and thus improves some clinical indicators in these patients.

Serum soluble Fas ligand is a severity and mortality prognostic marker for COVID-19 patients

Finding cytokine storm initiator factors associated with uncontrolled inflammatory immune response is necessary in COVID-19 patients. The aim was the identification of Fas/Fas Ligand (FasL) role in lung involvement and mortality of COVID-19 patients. In this case-control study, mild (outpatient), moderate (hospitalized), and severe (ICU) COVID-19 patients and healthy subjects were investigated. RNA isolated from PBMCs for cDNA synthesis and expression of mFas/mFasL mRNA was evaluated by RT-PCR. Serum sFas/sFasL protein by ELISA and severity of lung involvement by CT-scan were evaluated. Also, we docked Fas and FasL via Bioinformatics software (in silico) to predict the best-fit Fas/FasL complex and performed molecular dynamics simulation (MDS) in hyponatremia and fever (COVID-19 patients), and healthy conditions. mFasL expression was increased in moderate and severe COVID-19 patients compared to the control group. Moreover, mFas expression showed an inverse correlation with myalgia symptom in COVID-19 patients. Elevation of sFasL protein in serum was associated with reduced lung injury and mortality. Bioinformatics analysis confirmed that blood profile alterations of COVID-19 patients, such as fever and hyponatremia could affect Fas/FasL complex interactions. Our translational findings showed that decreased sFasL is associated with lung involvement; severity and mortality in COVID-19 patients. We think that sFasL is a mediator of neutrophilia and lymphopenia in COVID-19. However, additional investigation is suggested. This is the first report describing that the serum sFasL protein is a severity and mortality prognostic marker for the clinical management of COVID-19 patients.

Aging, testosterone, and neuroplasticity: friend or foe?

Neuroplasticity or neural plasticity implicates the adaptive potential of the brain in response to extrinsic and intrinsic stimuli. The concept has been utilized in different contexts such as injury and neurological disease. Neuroplasticity mechanisms have been classified into neuroregenerative and function-restoring processes. In the context of injury, neuroplasticity has been defined in three post-injury epochs. Testosterone plays a key yet double-edged role in the regulation of several neuroplasticity alterations. Research has shown that testosterone levels are affected by numerous factors such as age, stress, surgical procedures on gonads, and pharmacological treatments. There is an ongoing debate for testosterone replacement therapy (TRT) in aging men; however, TRT is more useful in young individuals with testosterone deficit and more specific subgroups with cognitive dysfunction. Therefore, it is important to pay early attention to testosterone profile and precisely uncover its harms and benefits. In the present review, we discuss the influence of environmental factors, aging, and gender on testosterone-associated alterations in neuroplasticity, as well as the two-sided actions of testosterone in the nervous system. Finally, we provide practical insights for further study of pharmacological treatments for hormonal disorders focusing on restoring neuroplasticity.

Neuropilin Is a New Player in the Pathogenesis of COVID-19

Abstract—A family of glycoproteins called neuropilins is gaining attention as a new contributor to the pathogenesis of COVID-19. The concept of penetration of SARS-CoV-2 into host cells is traditionally associated with the receptor role of the ACE2 protein. New evidence suggests that it is possible to enhance pulmonary viral infection by involvement of neuropilins. Neuropilins have two prominent features: (a) a wide range of participation in cellular and tissue processes; (b) a concomitant enhancement of effects associated with the co-reception of regulatory proteins. These features determine the special role of functionally disseminated neuropilins in the pathogenesis of vascular system damage, immunothrombosis, and organ damage with comorbid manifestations during COVID-19. However, the presentation of neuropilins as a generalized therapeutic target that has a corrective effect on the affected areas is an ambiguous approach and requires a selective strategy.

Covid-19-Induced Dysautonomia: A Menace of Sympathetic Storm

Among the plethora of debilitating neurological disorders of COVID-19 syndrome in survivors, the scope of SARS-CoV-2-induced dysautonomia (DNS) is yet to be understood, though the implications are enormous. Herein, we present an inclusive mini-review of SARS-CoV-2-induced DNS and its associated complications. Although, the direct link between Covid-19 and DSN is still speculative, the hypothetical links are thought to be either a direct neuronal injury of the autonomic pathway or a para/post-infectious immune-induced mechanism. SARS-CoV-2 infection-induced stress may activate the sympathetic nervous system (SNS) leading to neuro-hormonal stimulation and activation of pro-inflammatory cytokines with further development of sympathetic storm. Sympathetic over-activation in Covid-19 is correlated with increase in capillary pulmonary leakage, alveolar damage, and development of acute respiratory distress syndrome. Furthermore, SARS-CoV-2 can spread through pulmonary mechanoreceptors and chemoreceptors to medullary respiratory center in a retrograde manner resulting in sudden respiratory failure. Taken together, DSN in Covid-19 is developed due to sympathetic storm and inhibition of Parasympathetic nervous system-mediated anti-inflammatory effect with development of cytokine storm. Therefore, sympathetic and cytokine storms together with activation of Renin-Angiotensin-System are the chief final pathway involved in the development of DSN in Covid-19.