Promoting remyelination through cell transplantation therapies in a model of viral-induced neurodegenerative disease

Down-Regulation of p38 Mitogen-Activated Protein Kinases/Nuclear Factor Kappa Light Chain Enhancer of Activated B Cells (p38 MAPK/NF-κB) Signaling Pathway Promotes Bone Marrow Mesenchymal Stem Cells Differentiation into Neural Stem Cells in Healing Neurodegeneration

This study intends to promote bone marrow mesenchymal stem cells (BMSCs) differentiation into neural stem cells by down-regulating p38 MAPK/NF-κB to heal neurodegeneration. 26 patients with neurodegenerative diseases were enrolled from the Department of Neurology along with recruitment of 26 other healthy controls followed by analysis of p38 MAPK/NF-κB signaling pathway expression by ELISA. BMSCs were cultured and characterized by flow cytometry. Western blot and qRTPCR measured the p38 MAPK/NF-κB expression in the absence or presence of p38 MAPK/NF-κB inhibitors. p38 MAPK/NF-κB expression in 26 neurodegenerative patients was significantly higher than that of 26 healthy controls. The qRT-PCR and western blot results showed that the neural stem cell-specific proteins expression was increased as days went; after addition of p38 MAPK/NF-κB inhibitor, the expression of related specific genes were significantly decreased. In conclusion, inhibition of the expression of p38 MAPK/NF-κB signaling pathway can heal neurodegeneration by promoting the differentiation of BMSCs into neural stem cells.

The overall impact of COVID-19 on healthcare during the pandemic: A multidisciplinary point of view

BACKGROUND AND AIMS

The Coronavirus disease 2019 (COVID-19) pandemic globally changed the priorities of medical and surgical procedures. It has caused many healthcare systems to stop performing their routine screenings. Altering medical clinics to COVID-19 referral centers, lockdowns, and the public fear to refer to medical centers caused a significant reduction in the referral rate; especially in the elderly. This short review article highlights the transform in clinical practice during the post-COVID era and the need for future medical revolutions.

METHODS

A comprehensive literature search was separately performed by both authors. The articles published between 2019 and August 2021 were included in this study and selected according to a quality appraisal method.

RESULTS

We have summarized the possible corresponding changes in the diagnosis and treatment of all fields of medical care including internal medicine, surgical, and minor subcategories after the COVID-19 pandemic. We have also discussed the potential impacts of the pandemic on all these different categories and subcategories of medicine, including the outpatient setting and clinical work. We do believe that the lack of routine check-ups has led to an increase in the stage of disease in patients with a previously diagnosed problem. On the other hand, the dramatic change in the lifestyle of the population including restricted mobility and increased consumption of unhealthy food has caused metabolic syndrome and other new diseases that have not been diagnosed and properly managed.

CONCLUSION

Our findings revealed the urgent need for public health awareness. It indicated the need to carry out both psychological and screening approaches in the post-COVID era to not miss patients with a chronic disease and new cases who were undiagnosed during the COVID pandemic.

Emerging Roles of Coronavirus in Autoimmune Diseases

Virus infection can alter immune regulatory activity, and thus may be involved in the occurrence of autoimmune diseases. Recently, the pandemic of COVID-19 has posed a huge threat to public health and emerging evidence suggests that coronavirus may be implicated in the development and pathogenesis of autoimmune diseases. However, how coronavirus infection impacts the risk of autoimmune disease remains largely unknown. In this review, we focused on the association between coronavirus and autoimmunity, and elucidated the molecular mechanisms linking coronavirus exposure to autoimmunity. Additionally, we briefly introduced the role that coronavirus plays in several autoimmune diseases including multiple sclerosis (MS), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and idiopathicthrombocytopenic purpura (ITP).

Regulatory T cells promote remyelination in the murine experimental autoimmune encephalomyelitis model of multiple sclerosis following human neural stem cell transplant

Multiple sclerosis (MS) is a chronic, inflammatory autoimmune disease that affects the central nervous system (CNS) for which there is no cure. In MS, encephalitogenic T cells infiltrate the CNS causing demyelination and neuroinflammation; however, little is known about the role of regulatory T cells (Tregs) in CNS tissue repair. Transplantation of neural stem and progenitor cells (NSCs and NPCs) is a promising therapeutic strategy to promote repair through cell replacement, although recent findings suggest transplanted NSCs also instruct endogenous repair mechanisms. We have recently described that dampened neuroinflammation and increased remyelination is correlated with emergence of Tregs following human NPC transplantation in a murine viral model of immune-mediated demyelination. In the current study we utilized the prototypic murine autoimmune model of demyelination experimental autoimmune encephalomyelitis (EAE) to test the efficacy of hNSC transplantation. Eight-week-old, male EAE mice receiving an intraspinal transplant of hNSCs during the chronic phase of disease displayed remyelination, dampened neuroinflammation, and an increase in CNS CD4⁺CD25⁺FoxP3⁺ regulatory T cells (Tregs). Importantly, ablation of Tregs abrogated histopathological improvement. Tregs are essential for maintenance of T cell homeostasis and prevention of autoimmunity, and an emerging role for Tregs in maintenance of tissue homeostasis through interactions with stem and progenitor cells has recently been suggested. The data presented here provide direct evidence for collaboration between CNS Tregs and hNSCs promoting remyelination.

Regulatory T cells promote remyelination in the murine experimental autoimmune encephalomyelitis model of multiple sclerosis following human neural stem cell transplant

Multiple sclerosis (MS) is a chronic, inflammatory autoimmune disease that affects the central nervous system (CNS) for which there is no cure. In MS, encephalitogenic T cells infiltrate the CNS causing demyelination and neuroinflammation; however, little is known about the role of regulatory T cells (Tregs) in CNS tissue repair. Transplantation of neural stem and progenitor cells (NSCs and NPCs) is a promising therapeutic strategy to promote repair through cell replacement, although recent findings suggest transplanted NSCs also instruct endogenous repair mechanisms. We have recently described that dampened neuroinflammation and increased remyelination is correlated with emergence of Tregs following human NPC transplantation in a murine viral model of immune-mediated demyelination. In the current study we utilized the prototypic murine autoimmune model of demyelination experimental autoimmune encephalomyelitis (EAE) to test the efficacy of hNSC transplantation. Eight-week-old, male EAE mice receiving an intraspinal transplant of hNSCs during the chronic phase of disease displayed remyelination, dampened neuroinflammation, and an increase in CNS CD4⁺CD25⁺FoxP3⁺ regulatory T cells (Tregs). Importantly, ablation of Tregs abrogated histopathological improvement. Tregs are essential for maintenance of T cell homeostasis and prevention of autoimmunity, and an emerging role for Tregs in maintenance of tissue homeostasis through interactions with stem and progenitor cells has recently been suggested. The data presented here provide direct evidence for collaboration between CNS Tregs and hNSCs promoting remyelination.

Semaphorin4A causes loss of mature oligodendrocytes and demyelination in vivo

Background

Inappropriate contact between the immune system and the central nervous system is thought to be a cause of demyelination. We previously reported the ability of the class IV semaphorin, Semaphorin4A (Sema4A), to induce apoptosis in human oligodendrocytes; however, these results have yet to be translated to an in vivo setting. Importantly, HIV-associated neurocognitive disorder remains a significant complication for patients on combined anti-retroviral therapy, with white matter damage seen on MRI.

Methods

Human cerebrospinal fluid and serum was assayed for Sema4A using a Sema4A-specific ELISA. Wild-type mice were injected with Sema4A via stereotaxic infusion. Data was assessed for significance using unpaired t tests, comparing the corpus callosum of PBS-injected mice versus Sema4A-injected mice.

Results

Here, we demonstrate elevated levels of Sema4A in the cerebrospinal fluid and serum of people with HIV infection. Furthermore, we demonstrate that direct injection of Sema4A into the corpus callosum of mice results in loss of myelin architecture and decreased myelin, concomitant with apoptosis of mature myelinating oligodendrocytes. Sema4A injection also causes increased activation of microglia.

Conclusions

Taken together, our data further establish Sema4A as a potentially significant mediator of demyelinating diseases and a direct connection between the immune system and oligodendrocytes.

Innate Immune Responses and Viral-Induced Neurologic Disease

Multiple sclerosis (MS) is a disease of the central nervous system (CNS) characterized by chronic neuroinflammation, axonal damage, and demyelination. Cellular components of the adaptive immune response are viewed as important in initiating formation of demyelinating lesions in MS patients. This notion is supported by preclinical animal models, genome-wide association studies (GWAS), as well as approved disease modifying therapies (DMTs) that suppress clinical relapse and are designed to impede infiltration of activated lymphocytes into the CNS. Nonetheless, emerging evidence demonstrates that the innate immune response e.g., neutrophils can amplify white matter damage through a variety of different mechanisms. Indeed, using a model of coronavirus-induced neurologic disease, we have demonstrated that sustained neutrophil infiltration into the CNS of infected animals correlates with increased demyelination. This brief review highlights recent evidence arguing that targeting the innate immune response may offer new therapeutic avenues for treatment of demyelinating disease including MS.