Enhancing Cognitive Function of Healthy Wistar Rats with Aqueous Extract of Centella Asiatica

Background: Centella asiatica (L.) Urb is a native herb from Asian countries such as India, China, and Indonesia. This herb has been widely used as a cure for various diseases. However, studies investigating the aqueous extract of Centella asiatica as a nootropic in healthy individuals are still very limited.Objective: This study aims to investigate the potential of aqueous extract of Centella asiatica in enhancing cognitive function of healthy male Wistar rats.Methods: Rats were randomly allocated to four treatment groups, i.e. without treatment and aqueous Centella asiatica extract at doses of 200, 400 and 800 mg/kg. To determine enhancement of cognitive function, novel object recognition (NOR) test was conducted after the course of treatment. Acetylcholine content was assessed by enzyme-linked immunosorbent assay.Results: There was a significantly high preference index towards the novel object in the NOR test in groups treated with 200 mg/kg and 800 mg/kg of the aqueous extract compared to control. This was further confirmed by a significant increase of brain acetylcholine content in rats treated with 200 mg/kg of the extract.Conclusion: Therefore, this study confirms that the aqueous extract is effective in enhancing cognitive performance of healthy Wistar rats

A novel small molecule inhibitor of human Drp1

Mitochondrial dynamin-related protein 1 (Drp1) is a large GTPase regulator of mitochondrial dynamics and is known to play an important role in numerous pathophysiological processes. Despite being the most widely used Drp1 inhibitor, the specificity of Mdivi-1 towards human Drp1 has not been definitively proven and there have been numerous issues reported with its use including off-target effects. In our hands Mdivi-1 showed varying binding affinities toward human Drp1, potentially impacted by compound aggregation. Herein, we sought to identify a novel small molecule inhibitor of Drp1. From an initial virtual screening, we identified DRP1i27 as a compound which directly bound to the human isoform 3 of Drp1 via surface plasmon resonance and microscale thermophoresis. Importantly, DRP1i27 was found to have a dose-dependent increase in the cellular networks of fused mitochondria but had no effect in Drp1 knock-out cells. Further analogues of this compound were identified and screened, though none displayed greater affinity to human Drp1 isoform 3 than DRP1i27. To date, this is the first small molecule inhibitor shown to directly bind to human Drp1

Mdivi-1 protects human W8B2+Cardiac stem cells from oxidative stress and simulated ischemia-reperfusion injury

Cardiac stem cell (CSC) therapy is a promising approach to treat ischemic heart disease. However, the poor survival of transplanted stem cells in the ischemic myocardium has been a major impediment in achieving an effective cell-based therapy against myocardial infarction. Inhibiting mitochondrial fission has been shown to promote survival of several cell types. However, the role of mitochondrial morphology in survival of human CSC remains unknown. In this study, we investigated whether mitochondrial division inhibitor-1 (Mdivi-1), an inhibitor of mitochondrial fission protein dynamin-related protein-1 (Drp1), can improve survival of a novel population of human W8B2+ CSCs in hydrogen peroxide (H2O2)-induced oxidative stress and simulated ischemia-reperfusion injury models. Mdivi-1 significantly reduced H2O2-induced cell death in a dose-dependent manner. This cytoprotective effect was accompanied by an increased proportion of cells with tubular mitochondria, but independent of mitochondrial membrane potential recovery and reduction of mitochondrial superoxide production. In simulated ischemia-reperfusion injury model, Mdivi-1 given as a pretreatment or throughout ischemia-reperfusion injury significantly reduced cell death. However, the cytoprotective effect of Mdivi-1 was not observed when given at reperfusion. Moreover, the cytoprotective effect of Mdivi-1 in the simulated ischemia-reperfusion injury model was not accompanied by changes in mitochondrial morphology, mitochondrial membrane potential, or mitochondrial reactive oxygen species production. Mdivi-1 also did not affect mitochondrial bioenergetics of intact W8B2+ CSCs. Taken together, these experiments demonstrated that Mdivi-1 treatment of human W8B2+ CSCs enhances their survival and can be employed to improve therapeutic efficacy of CSCs for ischemic heart disease

New perspectives on the role of Drp1 isoforms in regulating mitochondrial pathophysiology

Mitochondria are dynamic organelles constantly undergoing fusion and fission. A concerted balance between the process of mitochondrial fusion and fission is required to maintain cellular health under different physiological conditions. Mutation and dysregulation of Drp1, the major driver of mitochondrial fission, has been associated with various neurological, oncological and cardiovascular disorders. Moreover, when subjected to pathological insults, mitochondria often undergo excessive fission, generating fragmented and dysfunctional mitochondria leading to cell death. Therefore, manipulating mitochondrial fission by targeting Drp1 has been an appealing therapeutic approach for cytoprotection. However, studies have been inconsistent. Studies employing Drp1 constructs representing alternate Drp1 isoforms, have demonstrated differing impacts of these isoforms on mitochondrial fission and cell death. Furthermore, there are distinct expression patterns of Drp1 isoforms in different tissues, suggesting idiosyncratic engagement in specific cellular functions. In this review, we will discuss these inherent variations among human Drp1 isoforms and how they could affect Drp1-mediated mitochondrial fission and cell death