No abstract

Our findings suggested that BDNF contributed to neuronal growth and proliferation and differentiation of NSCs in vitro by stimulating PI3K/AKT/GSK3β/β-catenin pathways.

The pandemic of COVID-19 caused by SARS-CoV-2 continues to spread despite the global efforts taken to control it. The 3C-like protease (3CLpro), the major protease of SARS-CoV-2, is one of the most interesting targets for antiviral drug development because it is highly conserved among SARS-CoVs and plays an important role in viral replication. Herein, we developed high throughput screening for SARS-CoV-2 3CLpro inhibitor based on AlphaScreen. We screened 91 natural product compounds and found that all-trans retinoic acid (ATRA), an FDA-approved drug, inhibited 3CLpro activity. The 3CLpro inhibitory effect of ATRA was confirmed in vitro by both immunoblotting and AlphaScreen with a 50% inhibition concentration (IC50) of 24.7 ± 1.65 µM. ATRA inhibited the replication of SARS-CoV-2 in VeroE6/TMPRSS2 and Calu-3 cells, with IC50 = 2.69 ± 0.09 µM in the former and 0.82 ± 0.01 µM in the latter. Further, we showed the anti-SARS-CoV-2 effect of ATRA on the currently circulating variants of concern (VOC); alpha, beta, gamma, and delta. These results suggest that ATRA may be considered as a potential therapeutic agent against SARS-CoV-2.

Brain-derived neurotrophic factor (BDNF) plays important roles in neural stem cell (NSC) growth. In this study, we investigated whether BDNF exerts its neurotrophic effects through the Wnt/β-catenin signaling pathway in human embryonic spinal cord NSCs (hESC-NSCs) in vitro. We found an increase in hESC-NSC growth by BDNF overexpression. Furthermore, expression of Wnt1, Frizzled1 and Dsh was upregulated, whereas GSK-3β expression was downregulated. In contrast, hESC-NSC growth was decreased by BDNF RNA interference. BDNF, Wnt1 and β-catenin components were all downregulated, whereas GSK-3β was upregulated. Next, we treated hESC-NSCs with 6-bromoindirubin-3'-oxime (BIO), a small molecule inhibitor of GSK-3β. BIO reduced the effects of BDNF upregulation/downregulation on the cell number, soma size and differentiation, and suppressed the effect of BDNF modulation on the Wnt signaling pathway. Our findings suggest that BDNF promotes hESC-NSC growth in vitro through crosstalk with the Wnt/β-catenin signaling pathway, and that this interaction may be mediated by GSK-3β.

Objective: The purpose of this paper was to study the protective effect of paeoniflorin on acute cerebral ischemia. The animal model of cerebral infarction induced by Middle Cerebral Artery Occlusion (MCAO) was blocked by the suture method. Sixty SD rats were randomly divided into the shame group, MCAO group, paeoniflorin (60, 120, 240 mg/kg, respectively) and Nimodipine (NMDP) group (n = 10 per group). Methods: The rats were intragastrically administered immediately after the operation. After 7 days of gavage, the brains were decapitated at 24 h. Hematoxylin and Eosin (HE) staining was used to observe the degree of cell damage in the cerebral cortex of rats. Immunohistochemistry was used to detect silver plating and to observe changes in nerve cells. Rats in the model group showed obvious symptoms of neurological deficits, such as the ischemic morphological changed, the Malondialdehyde (MDA), Lactate Dehydrogenase (LD) content and lactate dehydrogenase (LDH) activity were significantly increased in the ischemic brain tissue, while the Superoxide Dismutase (SOD) activity was decreased. Results: The decrease in Na+-K+-ATPase activity was significantly lower than that in the sham group. The neurological symptoms and signs of MCAO in the different doses of paeoniflorin group were improved, and the neuronal edema in the cortical area was alleviated. The activities of SOD, LDH and Na+-K+-ATPase were significantly increased, and the contents of MDA and LD were decreased. Conclusion: Therefore, paeoniflorin could alleviate the degree of tissue damage in rats with acute cerebral infarction, inhabit the formation of free radicals in the brain tissue after ischemia, and reduce the degree of lipid peroxidation. Thus, the degree of cell damage was reduced greatly and a protective effect was showed on cerebral ischemia.

The SIRT1 enzyme-stimulating and anti-glycation activities of Kaempferia parviflora extract and its main polymethoxyflavonoids were evaluated in vitro. K. parviflora extract elevated SIRT1 catalytic activity by eight-and 17-fold at 20 g/mL and 100 g/mL, respectively, compared with vehicle only. Two major polymethoxyflavonoids, 3,5,7,3',4'-pentamethoxyflavone (4) and 5,7,4'-trimethoxyflavone (5), were isolated from this extract and are four-and fivefold more potent than resveratrol, hitherto the strongest known natural SIRT1 activator. In addition, the anti-glycation activity of K. parviflora extract was observed to be seven times more effective than aminoguanidine, a clinical anti-diabetes drug. 3,5,7,3',4'-Pentamethoxyflavone (4) and 5,7,4'-trimethoxyflavone (5) showed the strongest anti-glycation activity among the tested polymethoxyflavonoids. Further comparison of the activity of these structurally related polymethoxyflavonoids revealed a possible structure-activity relationship, in particular, for the contribution of methoxy moieties.

Background: Brain-Derived Neurotrophic Factor (BDNF) plays critical roles during development of the central and peripheral nervous systems, as well as in neuronal survival after injury. Although proBDNF induces neuronal apoptosis after injury in vivo, whether it can also act as a death factor in vitro and in vivo under physiological conditions and after nerve injury, as well as its mechanism of inducing apoptosis, is still unclear. Objective: In this study, we investigated the mechanisms by which proBDNF causes apoptosis in sensory neurons and Satellite Glial Cells (SGCs) in Dorsal Root Ganglia (DRG) After Sciatic Nerve Transection (SNT). Methods: SGCs cultures were prepared and a scratch model was established to analyze the role of proBDNF in sensory neurons and SGCs in DRG following SNT. Following treatment with proBDNF antiserum, TUNEL and immunohistochemistry staining were used to detect the expression of Glial Fibrillary Acidic Protein (GFAP) and Calcitonin Gene-Related Peptide (CGRP) in DRG tissue; immunocytochemistry and Cell Counting Kit-8 (CCK8) assay were used to detect GFAP expression and cell viability of SGCs, respectively. RT-qPCR, western blot, and ELISA were used to measure mRNA and protein levels, respectively, of key factors in BDNF-TrkB, proBDNF-p75NTR/sortilin, and apoptosis signaling pathways. Results: proBDNF induced mitochondrial apoptosis of SGCs and neurons by modulating BDNF-TrkB and proBDNF-p75NTR/sortilin signaling pathways. In addition, neuroprotection was achieved by inhibiting the biological activity of endogenous proBDNF protein by injection of anti-proBDNF serum. Furthermore, the anti-proBDNF serum inhibited the activation of SGCs and promoted their proliferation. Conclusion: proBDNF induced apoptosis in SGCs and sensory neurons in DRG following SNT. The proBDNF signaling pathway is a potential novel therapeutic target for reducing sensory neuron and SGCs loss following peripheral nerve injury.

No abstract