SVHRSP Alleviates Age-Related Cognitive Deficiency by Reducing Oxidative Stress and Neuroinflammation.

BACKGROUND: Our previous studies have shown that scorpion venom heat-resistant synthesized peptide (SVHRSP) induces a significant extension in lifespan and improvements in age-related physiological functions in worms. However, the mechanism underlying the potential anti-aging effects of SVHRSP in mammals remains elusive. METHODS: Following SVHRSP treatment in senescence-accelerated mouse resistant 1 (SAMR1) or senescence-accelerated mouse prone 8 (SAMP8) mice, behavioral tests were conducted and brain tissues were collected for morphological analysis, electrophysiology experiments, flow cytometry, and protein or gene expression. The human neuroblastoma cell line (SH-SY5Y) was subjected to H2O2 treatment in cell experiments, aiming to establish a cytotoxic model that mimics cellular senescence. This model was utilized to investigate the regulatory mechanisms underlying oxidative stress and neuroinflammation associated with age-related cognitive impairment mediated by SVHRSP. RESULTS: SVHRSP significantly ameliorated age-related cognitive decline, enhanced long-term potentiation, restored synaptic loss, and upregulated the expression of synaptic proteins, therefore indicating an improvement in synaptic plasticity. Moreover, SVHRSP demonstrated a decline in senescent markers, including SA-ß-gal enzyme activity, P16, P21, SIRT1, and cell cycle arrest. The underlying mechanisms involve an upregulation of antioxidant enzyme activity and a reduction in oxidative stress-induced damage. Furthermore, SVHRSP regulated the nucleoplasmic distribution of NRF2 through the SIRT1-P53 pathway. Further investigation indicated a reduction in the expression of proinflammatory factors in the brain after SVHRSP treatment. SVHRSP attenuated neuroinflammation by regulating the NF-κB nucleoplasmic distribution and inhibiting microglial and astrocytic activation through the SIRT1-NF-κB pathway. Additionally, SVHRSP significantly augmented Nissl body count while suppressing neuronal loss. CONCLUSION: SVHRSP could remarkably improve cognitive deficiency by inhibiting oxidative stress and neuroinflammation, thus representing an effective strategy to improve brain health.

Scorpion venom heat-resistant synthesized peptide ameliorates epileptic seizures and imparts neuroprotection in rats mediated by NMDA receptors.

Finding new and effective natural products for designing antiepileptic drugs is highly important in the scientific community. The scorpion venom heat-resistant peptide (SVHRP) was purified from Buthus martensii Karsch scorpion venom, and subsequent analysis of the amino acid sequence facilitated the synthesis of a peptide known as scorpion venom heat-resistant synthesis peptide (SVHRSP) using a technique for peptide synthesis. Previous studies have demonstrated that the SVHRSP can inhibit neuroinflammation and provide neuroprotection. This study aimed to investigate the antiepileptic effect of SVHRSP on both acute and chronic kindling seizure models by inducing seizures in male rats through intraperitoneal administration of pentylenetetrazole (PTZ). Additionally, an N-methyl-D-aspartate (NMDA)-induced neuronal injury model was used to observe the anti-excitotoxic effect of SVHRSP in vitro. Our findings showed that treatment with SVHRSP effectively alleviated seizure severity, prolonged latency, and attenuated neuronal loss and glial cell activation. It also demonstrated the prevention of alterations in the expression levels of NMDA receptor subunits and phosphorylated p38 MAPK protein, as well as an improvement in spatial reference memory impairment during Morris water maze (MWM) testing in PTZ-kindled rats. In vitro experiments further revealed that SVHRSP was capable of attenuating neuronal action potential firing, inhibiting NMDA receptor currents and intracellular calcium overload, and reducing neuronal injury. These results suggest that the antiepileptic and neuroprotective effects of SVHRSP may be mediated through the regulation of NMDA receptor function and expression. This study provides new insight into therapeutic strategies for epilepsy.

NLRP3 mediates the neuroprotective effects of SVHRSP derived from scorpion venom in rotenone-induced experimental Parkinson's disease model.

ETHNOPHARMACOLOGICAL RELEVANCE: In traditional Chinese medicine, scorpion is used to treat diseases with symptoms such as trembling, convulsion and dementia. Our laboratory employs patented technology to extract and purify the active single component from scorpion venom. We then utilize mass spectrometry to determine the amino acid sequence of the polypeptide and synthesize it artificially to acquire the polypeptide with a purity of 99.3%, named SVHRSP (Scorpion Venom Heat-Resistant Peptide). SVHRSP has been demonstrated to display potent neuroprotective efficacy in Parkinson's disease. AIM OF THE STUDY: To explore the molecular mechanisms and potential molecular targets of SVHRSP-afforded neuroprotection in PD mouse models, as well as to investigate the role of NLRP3 in SVHRSP-mediated neuroprotection. MATERIALS AND METHODS: The PD mouse model was induced by rotenone and the neuroprotective role of SVHRSP on the PD mouse model was measured using the gait test, rotarod test, the number of dopaminergic neurons, and the activation of microglia. RNA sequencing and GSEA analysis were performed to find the differentially biological pathways regulated by SVHRSP. Primary mid-brain neuron-glial cultures and NLRP3-/- mice were applied to verify the role of NLRP3 by using qRT-PCR, western blotting, enzyme-linked immunosorbent assay (ELISA) and immunostaining. RESULTS: SVHRSP-afforded dopaminergic neuroprotection was accompanied with inhibition of microglia-mediated neuroinflammatory pathways. Importantly, depletion of microglia markedly reduced the neuroprotective efficacy of SVHRSP against rotenone-induced dopaminergic neurotoxicity in vitro. SVHRSP inhibited microglial NOD-like receptor pathway, mRNA expression and protein level of NLRP3 in rotenone PD mice. SVHRSP also reduced rotenone-induced caspse-1 activation and IL-1ß maturation, indicating that SVHRSP mitigated activation of NLRP3 inflammasome. Moreover, inactivation of NLRP3 inflammasome by MCC950 or genetic deletion of NLRP3 almost abolished SVHRSP-afforded anti-inflammatory, neuroprotective effects and improvement of motor performance in response to rotenone. CONCLUSIONS: NLRP3 mediated the neuroprotective effects of SVHRSP in rotenone-induced experimental PD model, providing additional evidence for the mechanisms of SVHRSP-afforded anti-inflammatory and neuroprotective effects in PD.

Scorpion venom heat-resistant synthetic peptide protects dopamine neurons against 6-hydroxydopamine neurotoxicity in C. elegans.

Parkinson's disease (PD) is a common neurodegenerative disease. The main pathological feature is the degeneration and loss of dopaminergic neurons in the substantia nigra, which leads to the significant decrease of dopamine content in the striatum. Our recent studies have shown that scorpion venom heat-resistant synthetic peptide (SVHRSP) have protective effects on neuroinflammation. In this study, using C. elegans induced by 6-hydroxydopamine (6-OHDA) as neurodegenerative model, we investigated the effect of SVHRSP on dopaminergic neurons neurotoxicity. Our results implied that SVHRSP treatment could improve the motor capacity in 6-OHDA-induced C. elegans and improve dopaminergic neuron mediated food sensitivity behavior. After SVHRSP treatment, dopaminergic neuron degeneration induced by 6-OHDA was significantly prevented along with a decreased α-synuclein aggregation and restored lipid deposition in C. elegans induced by 6-OHDA. We also observed the reduced levels of reactive oxygen species (ROS) after SVHRSP treatment in model-building C. elegans. In addition, the genes related to apoptosis, oxidative stress, like ctl-1, egl-1and cat-2 in C. elegans induced by 6-OHDA upregulated after treatment with SVHRSP. In conclusion, SVHRSP may impose anti-PD effect through its neuroprotective action on dopaminergic neurons. This study elucidates the effect and related mechanism of SVHRSP on PD and provides evidences for the therapeutic treatment of PD.

Scorpion Venom Heat-Resistant Synthesized Peptide Increases Stress Resistance and Extends the Lifespan of Caenorhabditis elegans via the Insulin/IGF-1-Like Signal Pathway.

Improving healthy life expectancy by targeting aging-related pathological changes has been the spotlight of geroscience. Scorpions have been used in traditional medicine in Asia and Africa for a long time. We have isolated heat-resistant peptides from scorpion venom of Buthusmartensii Karsch (SVHRP) and found that SVHRP can attenuate microglia activation and protect Caenorhabditis elegans (C. elegans) against ß-amyloid toxicity. Based on the amino acid sequence of these peptides, scorpion venom heat-resistant synthesized peptide (SVHRSP) was prepared using polypeptide synthesis technology. In the present study, we used C. elegans as a model organism to assess the longevity-related effects and underlying molecular mechanisms of SVHRSP in vivo. The results showed that SVHRSP could prolong the lifespan of worms and significantly improve the age-related physiological functions of worms. SVHRSP increases the survival rate of larvae under oxidative and heat stress and decreases the level of reactive oxygen species and fat accumulation in vivo. Using gene-specific mutation of C. elegans, we found that SVHRSP-mediated prolongation of life depends on Daf-2, Daf-16, Skn-1, and Hsf-1 genes. These results indicate that the antiaging mechanism of SVHRSP in nematodes might be mediated by the insulin/insulin-like growth factor-1 signaling pathway. Meanwhile, SVHRSP could also up-regulate the expression of stress-inducing genes Hsp-16.2, Sod-3, Gei-7, and Ctl-1 associated with aging. In general, our study may have important implications for SVHRSP to promote healthy aging and provide strategies for research and development of drugs to treat age-related diseases.

A novel synthetic peptide SVHRSP attenuates dopaminergic neurodegeneration by inhibiting NADPH oxidase-mediated neuroinflammation in experimental models of Parkinson's disease.

Current treatment of Parkinson's disease (PD) ameliorates symptoms but fails to block disease progression. This study was conducted to explore the protective effects of SVHRSP, a synthetic heat-resistant peptide derived from scorpion venom, against dopaminergic neurodegeneration in experimental models of PD. Results showed that SVHRSP dose-dependently reduced the loss of dopaminergic neuron in the nigrostriatal pathway and motor impairments in both rotenone and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid (MPTP/p)-induced mouse PD models. Microglial activation and imbalance of M1/M2 polarization were also abrogated by SVHRSP in both models. In rotenone-treated primary midbrain neuron-glial cultures, loss of dopaminergic neuron and microglial activation were mitigated by SVHRSP. Furthermore, lipopolysaccharide (LPS)-elicited microglial activation, M1 polarization and related dopaminergic neurodegeneration in primary cultures were also abrogated by SVHRSP, suggesting that inhibition of microglial activation contributed to SVHRSP-afforded neuroprotection. Mechanistic studies revealed that SVHRSP blocked both LPS- and rotenone-induced microglial NADPH oxidase (NOX2) activation by preventing membrane translocation of cytosolic subunit p47phox. NOX2 knockdown by siRNA markedly attenuated the inhibitory effects of SVHRSP against LPS- and rotenone-induced gene expressions of proinflammatory factors and related neurotoxicity. Altogether, SVHRSP protects dopaminergic neurons by blocking NOX2-mediated microglial activation in experimental PD models, providing experimental basis for the screening of clinical therapeutic drugs for PD.

Scorpion venom heat-resistant synthesized peptide ameliorates 6-OHDA-induced neurotoxicity and neuroinflammation: likely role of Nav 1.6 inhibition in microglia.

BACKGROUND AND PURPOSE: Microglia-related inflammation is associated with the pathology of Parkinson's disease. Functional voltage-gated sodium channels (VGSCs) are involved in regulating microglial function. Here, we aim to investigate the effects of scorpion venom heat-resistant synthesized peptide (SVHRSP) on 6-hydroxydopamine (6-OHDA)-induced Parkinson's disease-like mouse model and reveal its underlying mechanism. EXPERIMENTAL APPROACH: Unilateral brain injection of 6-OHDA was performed to establish Parkinson's disease mouse model. After behaviour test, brain tissues were collected for morphological analysis and protein/gene expression examination. Primary microglia culture was used to investigate the role of sodium channel Nav 1.6 in the regulation of microglia inflammation by SVHRSP. KEY RESULTS: SVHRSP treatment attenuated motor deficits, dopamine neuron degeneration, activation of glial cells and expression of pro-inflammatory cytokines induced by 6-OHDA lesion. Primary microglia activation and the production of pro-inflammatory cytokines induced by lipopolysaccharide (LPS) were also suppressed by SVHRSP treatment. In addition, SVHRSP could inhibit mitogen-activated protein kinases (MAPKs) pathway, which plays pivotal roles in the pro-inflammatory response. Notably, SVHRSP treatment suppressed the overexpression of microglial Nav 1.6 induced by 6-OHDA and LPS. Finally, it was shown that the anti-inflammatory effect of SVHRSP in microglia was Nav 1.6 dependent and was related to suppression of sodium current and probably the consequent Na+ /Ca2+ exchange. CONCLUSIONS AND IMPLICATIONS: SVHRSP might inhibit neuroinflammation and protect dopamine neurons via down-regulating microglial Nav 1.6 and subsequently suppressing intracellular Ca2+ accumulation to attenuate the activation of MAPKs signalling pathway in microglia.