NEP1-40-overexpressing neural stem cells enhance axon regeneration by inhibiting Nogo-A/NgR1 signaling pathway

Background: Nogo-66 antagonistic peptide (NEP1-40) offers the potential to improve spinal cord injury (SCI). Objective: To explore the effect of NEP1-40 overexpression on neural stem cells (NSCs) regulating the axon regeneration of injured neurons. Methods: We isolated NSCs from brain tissues of pregnant rat fetuses and used Nestin immunofluorescence to identify them. The NEP1-40 overexpressing NSCs were constructed by transfection with the NEP1-40-overexpressing vector. The expression of NSCs differentiation associated markers including Tuj-1, GFAP, Oligo2 and MBP, were detected by RT-PCR, western blotting and immunofluorescence. NeuN immunofluorescence staining was used to measure the number of neurons. And western blotting was used to detect the phosphorylation levels of LIMK1/2, cofilin and MLC-2 and the protein levels of GAP-43, MAP-2 and APP. Results: The NEP1-40 overexpression promoted the expression level of Tuj-1, Oligo2 and MBP, and increased the number of Tuj-1, Oligo2 and MBP positive cells. NEP1-40-overexpressing NSCs (NEP-NSCs) improved NeuN positive cells of co-culture with injured neurons. And NEP-NSCs also increased the protein levels of axon regeneration indicators (GAP-43, MAP-2) and decreased APP protein level. In addition, the phosphorylation level of LIMK1/2, cofilin and MLC-2 were markedly decreased in NEP-NSCs. Conclusion: NEP1-40 overexpression enhanced the ability of NSCs differentiation into neurons and promoted axon regeneration by inhibiting the Nogo-A/NgR1 signaling pathway. This study provides an alternative gene modified transplantation NSCs for the SCI treatment.

An Antagonistic Peptide of Gpr1 Ameliorates LPS-Induced Depression through the Hypothalamic-Pituitary-Ovarian Axis

Depression affects the reproductive axis at the hypothalamus and pituitary levels, which has a significant impact on female fertility. It has been reported that G protein-coupled receptor 1 (Gpr1) mRNA is expressed in both the hypothalamus and ovaries. However, it is unclear whether there is a relationship between Gpr1 and depression, and its role in ovarian function is unknown. Here, the expression of Gpr1 was recorded in the hypothalamus of normal female mice, and co-localized with gonadotrophin-releasing hormone (GnRH) and corticotropin-releasing factor (CRF). We established a depression mouse model to evaluate the antidepressant effect of G5, an antagonistic peptide of Gpr1. The results show that an intraperitoneal injection of G5 improves depressant–like behaviors remarkably, including increased sucrose intake in the sucrose preference test and decreased immobility time in the forced swimming tests. Moreover, G5 treatment increased the release of reproductive hormone and the expression of ovarian gene caused by depression. Together, our findings reveal a link between depression and reproductive diseases through Gpr1 signaling, and suggest antagonistic peptide of Gpr1 as a potential therapeutic application for hormone-modulated depression in women.

PTEN Blocking Stimulates Corticospinal and Raphespinal Axonal Regeneration and Promotes Functional Recovery After Spinal Cord Injury

The long-term disabilities associated with spinal cord injury (SCI) are primarily due to the absence of robust neuronal regeneration and functional plasticity. The inability of the axon to regenerate after SCI is contributed by several intrinsic factors that trigger a cascade of molecular growth program and modulates axonal sprouting. Phosphatase and tensin homolog (PTEN) is one of the intrinsic factors contributing to growth failure after SCI, however, the underlying mechanism is not well known. Here, we developed a novel therapeutic approach for treating SCI by suppressing the action of PTEN in a mouse model of hemisection SCI. We have used a novel peptide, PTEN antagonistic peptide (PAP) to block the critical domains of PTEN to demonstrate its ability to potentially promote axon growth. PAP treatment not only enhanced regeneration of corticospinal axons into the caudal spinal cord but also promoted the regrowth of descending serotonergic axons in SCI mice. Furthermore, expression levels of p-mTOR, p-S6, p-Akt, p-Erk, p-GSK, p-PI3K downstream of PTEN signaling pathway were increased significantly in the spinal cord of SCI mice systemically treated with PAP than control TAT peptide-treated mice. Our novel strategy of administering deliverable compounds postinjury may facilitate translational feasibility for central nervous system injury.

SARS-CoV-2 Spike protein promotes hyper-inflammatory response that can be ameliorated by Spike-antagonistic peptide and FDA-approved ER stress and MAP kinase inhibitors in vitro

SummarySARS-CoV-2 infection causes an inflammatory cytokine storm and acute lung injury. Currently there are no effective antiviral and/or anti-inflammatory therapies. Here we demonstrate that 2019 SARS-CoV-2 spike protein subunit 1 (CoV2-S1) induces high levels of NF-κB activations, production of pro-inflammatory cytokines and mild epithelial damage, in human bronchial epithelial cells. CoV2-S1-induced NF-κB activation requires S1 interaction with human ACE2 receptor and early activation of endoplasmic reticulum (ER) stress, and associated unfolded protein response (UPR), and MAP kinase signalling pathways. We developed an antagonistic peptide that inhibits S1-ACE2 interaction and CoV2-S1-induced productions of pro-inflammatory cytokines. The existing FDA-approved ER stress inhibitor, 4-phenylburic acid (4-PBA), and MAP kinase inhibitors, trametinib and ulixertinib, ameliorated CoV2-S1-induced inflammation and epithelial damage. These novel data highlight the potentials of peptide-based antivirals for novel ACE2-utilising CoVs, while repurposing existing drugs may be used as treatments to dampen elevated inflammation and lung injury mediated by SARS-CoV-2.