AMP-activated protein kinase as a mediator of mitochondrial dysfunction of multiple sclerosis in animal models: A systematic review.

Multiple sclerosis (MS) is a chronic central nervous system (CNS) disorder characterized by demyelination, neuronal damage, and oligodendrocyte depletion. Reliable biomarkers are essential for early diagnosis and disease management. Emerging research highlights the role of mitochondrial dysfunction and oxidative stress in CNS disorders, including MS, in which mitochondria are central to the degenerative process. Adenosine monophosphate-activated protein kinase (AMPK) regulates the mitochondrial energy balance and initiates responses in neurodegenerative conditions. This systematic review, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, aimed to comprehensively assess the literature on AMPK pathways, mitochondrial dysfunction, and in vivo studies using MS animal models. The search strategy involved the use of AMPK syntaxes, MS syntaxes, and animal model syntaxes. The PubMed, Scopus, Web of Science, and Google Scholar databases were systematically searched on August 26, 2023 without publication year restrictions. The review identified and analyzed relevant papers to provide a comprehensive overview of the current state of related research. Eight studies utilizing various interventions and methodological approaches were included. Risk of bias assessment revealed some areas of low risk but lacked explicit reporting in others. These studies collectively revealed a complex relationship between AMPK, mitochondrial dysfunction, and MS pathogenesis, with both cuprizone and experimental autoimmune encephalomyelitis models demonstrating associations between AMPK and mitochondrial disorders, including oxidative stress and impaired expression of mitochondrial genes. These studies illuminate the multifaceted role of AMPK in MS animal models, involving energy metabolism, inflammatory processes, oxidative stress, and gene regulation leading to mitochondrial dysfunction. However, unanswered questions about its mechanisms and clinical applications underscore the need for further research to fully harness its potential in addressing MS-related mitochondrial dysfunction.

Efficacy of clofazimine against acute and chronic Toxoplasma gondii infection in mice.

Toxoplasmosis is a zoonotic protozoal disease affecting approximately one-third of the world's population. The lack of current treatment options necessitates the development of drugs with good tolerance and effectiveness on the active and cystic stages of the parasite. The present study was established to investigate, for the first time, the potential potency of clofazimine (CFZ) against acute and chronic experimental toxoplasmosis. For this purpose, the type II T. gondii (Me49 strain) was used for induction acute (20 cysts in each mouse) and chronic (10 cysts in each mouse) experimental toxoplasmosis. The mice were treated with 20 mg/kg of CFZ intraperitoneally and orally. The histopathological changes, brain cyst count, total Antioxidant Capacity (TAC), malondialdehyde (MDA) assay, and the level of INF-γ were also evaluated. In the acute toxoplasmosis, both IP and oral administration of CFZ induced a significant reduction in brain parasite burden by 90.2 and 89%, respectively, and increased the survival rate to 100% compared with 60% in untreated controls. In the chronic infection, cyst burden decreased at 85.71 and 76.18% in CFZ-treated subgroups in comparison to infected untreated controls. In addition, 87.5% and 100% of CFZ-treated subgroups survived versus untreated control 62.5%. Moreover, CFZ significantly increased INF-γ levels in acute and chronic toxoplasmosis. Tissue inflammatory lesions were considerably reduced in the CFZ-treated chronic subgroups. CFZ treatment significantly reduced MDA levels and elevated TAC in both acute and chronic infections. In conclusion, CFZ showed a promising finding regarding the ability to reduce cyst burden in acute and chronic infection. Further studies are needed to investigate the therapeutic role of CFZ on toxoplasmosis using the long-term treatment and more advanced approaches. In addition, clofazimine may need to be accompanied by another drug to augment its effect and prevent the regrowth of parasites.

Impact of disease-modifying drugs on the severity of COVID-19 infection in multiple sclerosis patients.

Recent evidence suggested that neurological manifestations occur in patients with a severe form of coronavirus disease (COVID-19). On the basis of this issue, neurologists are very concerned about patients with neurological disorders, especially multiple sclerosis (MS), as consumers of immunosuppressive or immune-modulating drugs. Therefore, the administration of proper disease-modifying therapies (DMTs) in MS patients is critical during the pandemic status. On the one hand, both the autoimmune diseases and immunosuppressive drugs increase the risk of infection due to impairment in the immune system, and on the other hand, postponing of MS treatment has serious consequences on the central nervous system. In the present study, we discussed recent literature about the effect of DMTs administration on the severity of COVID-19 in the MS patients. Overall, it seems that DMTs do not provoke the COVID-19 infection in the MS patients by declining immune responses and cytokine storm. However, as a precaution, the supervision of a neurologist is highly recommended.

The role of inflammasomes in multiple sclerosis.

Multiple sclerosis (MS) is considered as an inflammatory autoimmune disease of the central nervous system (CNS), with a complex and heterogenic etiology. However, the involvement of inflammation in its pathophysiology is well documented and current therapies for MS are mainly immunosuppressive drugs. Although the available drugs reduce new lesions and relapses, their long-term outcome is not completely satisfactory. Inflammasomes are multimeric protein complexes that play a critical role in the inflammatory process. Several lines of evidence suggest an association between inflammasome activation and MS. In this paper, we have reviewed current studies that demonstrate the involvement of inflammasomes in MS development, in both animal model and MS patients. Furthermore, prior studies about the effect of inflammasome inhibitor drugs on development and progression of MS are discussed.

Association between rs3088440 (G > A) polymorphism at 9p21.3 locus with the occurrence and severity of coronary artery disease in an Iranian population.

BACKGROUND: Several genome-wide association studies showed that a series of genetic variants located at the chromosome 9p21 locus are strongly associated with coronary artery disease (CAD). RATIONALE AND PURPOSE OF THE STUDY: In the present study, the relationship of rs3088440 (G > A) in cyclin-dependent kinase inhibitor 2A (CDKN2A) gene site with the presence of coronary artery disease (CAD) and its severity was evaluated in an Iranian population. METHODS AND RESULTS: The presence of rs3088440 (G > A) genotypes was assessed by polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) technique in 324 CAD patients and 148 normal controls. rs3088440 (G > A) polymorphism was associated with increased risk of CAD in the total population (adjusted OR = 1.76, 95% CI = 1.10-2.82; p-value = 0.017) or in women (adjusted OR = 2.96, 95% CI = 1.34-6.55; p-value = 0.007), but not in the men (adjusted OR = 1.35, 95% CI = 0.70-2.6; p-value = 0.368). CONCLUSIONS: Our findings suggest that the presence of rs3088440 (G > A) is potentially linked with the risk of CAD and its severity in whole study subjects or in women only, independent of CAD risk factors.

Direct conversion of somatic cells towards oligodendroglial lineage cells: A novel strategy for enhancement of myelin repair.

Oligodendrocyte precursor cells (OPCs) are considered as the main cell source for myelination in the central nervous system. Following demyelination, proliferation, migration, and differentiation capability of endogenous OPCs remarkably increase leading to remyelination in damaged areas. Despite the beneficial impacts of resident OPCs for myelin repair, the capacity of endogenous repair is low and insufficient. Therefore, several strategies have been developed to improve endogenous myelin repair. Although stem cell therapy has been introduced as a promising strategy for neurodegenerative disorders, but several limitations such as cell rejection, teratoma formation, and ethical concerns have hampered the extensive application of stem cells in clinic. In recent years, direct conversion of fully differentiated somatic cells into desired cells in the lesion area has opened a new era in regenerative medicine. In addition to direct reprogramming of somatic cells to neurons, recent evidence have also demonstrated that somatic cells, including fibroblasts and astrocytes, can be directly reprogrammed to OPC-like cells by overexpression of some specific transcription factors, microRNAs, or application of small molecules. Interestingly, induced OPCs differentiated to myelinating oligodendrocytes that could effectively ensheath the host axons. In the present review article, the current advancements in direct conversion of somatic cells towards oligodendroglial cells have been discussed both in vitro and in vivo.

Possible regenerative effects of fingolimod (FTY720) in multiple sclerosis disease: An overview on remyelination process.

Fingolimod (FTY720) is a sphingosine 1-phosphate (S1P) receptor analog, which has been approved as an oral immunomodulator for treating relapsing-remitting multiple sclerosis. This drug prevents lymphocyte egression from lymph nodes and reduces the infiltration of inflammatory mediators into the central nervous system. Based on its lipophilic nature, FTY720 passes through the blood-brain barrier and can directly affect neural cells. A notably different subtype of S1P receptors expresses in neural cells, which suggests FTY720 is a drug capable of affecting neural cells. Oligodendrocytes (OLs) are considered as the primary target cells in MS. Remyelination is a process including the proliferation of neural progenitors and oligodendrocyte precursor cells, their migration to the lesion site and their differentiation to mature oligodendrocytes. Experimental and clinical studies have described the impact of FTY720 on endogenous remyelination elements. In this review, we will explain the current clinical and experimental evidence that exists on the effects of FTY720 on remyelination and the underlying mechanisms.

Update on cerebrovascular manifestations of COVID-19.

The novel member of coronaviruses family, severe acute respiratory coronavirus-2 (SARS-CoV-2), with high structural homology to SARS-CoV and Middle East respiratory syndrome-related coronavirus (MERS) has spread rapidly with about 20 million cases infection and over 700,000 deaths. SARS-CoV-2 has been emerged as a worldwide disaster due to non-specific few respiratory and gastrointestinal manifestations at the onset of disease as well as long incubation period. Surprisingly, not only respiratory failure but also the underlying coagulation disorder and neurovascular involvement worsen the clinical outcome of infected patients. In this review article, we describe the probable mechanisms of SARS-CoV-2 infection and stroke occurrence. We will also discuss the cerebrovascular events following SARS-CoV-2 infection, the recommended therapies, and future prospects to better manage these patients in coronavirus disease 2019 (COVID-19) outbreak.

miR-302/367-induced neurons reduce behavioral impairment in an experimental model of Alzheimer's disease.

In vivo reprogramming of reactive glial cells to neurons has opened a new horizon in regenerative medicine. Our previous study showed that astrocytes could be converted to neurons by the microRNA-302/367 (miR-302/367) cluster in adult brains. In this study, we investigated the possible contribution of miR-302/367-induced neurons in behavioral improvement and neural repair in an Alzheimer's disease (AD) animal model. The AD model was induced by an intracerebroventricular (i.c.v) injection of streptozotocin (STZ). GFP-only or miR-302/367+GFP expressing lentiviral particles were injected into the dentate gyrus of the hippocampus along with intraperitoneal (i.p) valproate (VPA) injection, 3weeks after the STZ administration. We assessed short-term and spatial memories by the Y-maze and Morris water maze (MWM) tasks, respectively. Electrophysiological activities of induced neuron-like cells were investigated using a whole-cell patch clamp technique, 6months after injection of miR-302/367. Behavioral analysis showed that the STZ injection significantly impaired short-term memory and increased escape latency parameter in the MWM task. Compared to STZ and STZ+VPA groups, miR-302/367 combined with VPA significantly improved the spontaneous alternation and spatial memory. Immunostaining against NeuN, as a mature neuronal marker, and its quantification indicated that co-labeled GFP and NeuN significantly increased in the miR-302/367+VPA group. Induced neurons were detected 6months after the miR-302/367 injection. The patch-clamp recording suggested that induced neurons could fire repetitive action potential like endogenous neurons. In conclusion, our results indicated that in vivo reprogramming of reactive astrocytes to neurons by the miR-302/367 cluster might be considered as a novel strategy to restore learning and memory in AD patients.

Arbutin reduces cognitive deficit and oxidative stress in animal model of Alzheimer's disease.

Objectives: Recent evidences have shown the beneficial effects of natural products for treating of Alzheimer's disease (AD). Arbutin is derived from Pyrus biossieriana and exerts a wide range of pharmacological activities including anti-inflammatory and anti-oxidant effects. The present study was designed to examine the protective effects of arbutin on streptozotocin (STZ)-induced neurotoxicity in rats. Materials and methods: The spatial memory impairment was induced by intracerebroventricular (i.c.v) microinjection of STZ (3 mg/kg, 10 µL). Animals received the pretreatment of arbutin (50 mg/kg) for 21 days before STZ injection. The Morris Water maze (MWM) task was used to study the spatial learning and memory. The levels of oxidative stress markers including malondialdehyde (MDA), nitrite and carbonyl were measured in serum and hippocampus samples. In addition, antioxidant level was assessed by ferric reducing antioxidant power (FRAP) test. Results: The obtained result indicated that administration of STZ is led to memory impairment and increases the levels of oxidative stress markers in the hippocampus tissues. Conversely, arbutin improves spatial memory and reduces oxidative and nitrosative stress, as evidenced by a significant decrease in the amount of MDA and nitrite in the serum and hippocampus. In addition, an increase in FRAP levels of hippocampus was observed in arbutin receiving animals. The protein carbonyl content was not reduced in arbutin receiving animals. Conclusion: It could be concluded that arbutin protects the brain against STZ-induced memory impairment and oxidative damage in the hippocampus. The neuroprotective effect of arbutin might be mediated through its antioxidant and free radical scavenging effects.