OL-FS13 alleviates experimental cerebral ischemia-reperfusion injury

Newly identified peptide Nigrocin-OA27 inhibits UVB induced melanin production via the MITF/TYR pathway

Melasma is a common skin disease induced by an increase in the content of melanin in the skin, which also causes serious physical and mental harm to patients. In this research, a novel peptide (Nigrocin-OA27) from Odorrana andersonii is shown to exert a whitening effect on C57 mice pigmentation model. The peptide also demonstrated non-toxic and antioxidant capacity, and can significantly reduce melanin content in B16 cells. Topical application effectively delivered Nigrocin-OA27 to skin's epidermal and dermal layers and exhibited significant preventive and whitening effects on the UVB-induced ear pigmentation model in C57 mice. The whitening mechanism of Nigrocin-OA27 may be related to reduced levels of the microphthalmia-associated transcription factor and the key enzyme for melanogenesis-tyrosinase (TYR). Nigrocin-OA27 also inhibited the catalytic activity by adhering to the active core of TYR, thereby reducing melanin formation and deposition. In conclusion, Nigrocin-OA27 may be a potentially effective external agent to treat melasma by inhibiting aberrant skin melanin synthesis.

Hydrogel Loaded with Peptide-Containing Nanocomplexes: Symphonic Cooperation of Photothermal Antimicrobial Nanoparticles and Prohealing Peptides for the Treatment of Infected Wounds

Current treatment for chronic infectious wounds is limited due to severe drug resistance in certain bacteria. Therefore, the development of new composite hydrogels with nonantibiotic antibacterial and pro-wound repair is important. Here, we present a photothermal antibacterial composite hydrogel fabricated with a coating of Fe2+ cross-linked carboxymethyl chitosan (FeCMCS) following the incorporation of melanin nanoparticles (MNPs) and the CyRL-QN15 peptide. Various physical and photothermal properties of the hydrogel were characterized. Cell proliferation, migration, cycle, and free-radical scavenging activity were assessed, and the antimicrobial properties of the hydrogel were probed by photothermal therapy. The effects of the hydrogel were validated in a model of methicillin-resistant Staphylococcus aureus (MRSA) infection with full-thickness injury. This effect was further confirmed by changes in cytokines associated with inflammation, re-epithelialization, and angiogenesis on the seventh day after wound formation. The MNPs demonstrated robust photothermal conversion capabilities. The composite hydrogel (MNPs/CyRL-QN15/FeCMCS) promoted keratinocyte and fibroblast proliferation and migration while exhibiting high antibacterial efficacy, effectively killing more than 95% of Gram-positive and Gram-negative bacteria. In vivo study using an MRSA-infected full-thickness injury model demonstrated good therapeutic efficacy of the hydrogel in promoting regeneration and remodeling of chronically infected wounds by alleviating inflammatory response and accelerating re-epithelialization and collagen deposition. The MNPs/CyRL-QN15/FeCMCS hydrogel showed excellent antibacterial and prohealing effects on infected wounds, indicating potential as a promising candidate for wound healing promotion.

Amphibian-derived peptide RL-RF10 ameliorates paraquat-induced pulmonary fibrosis injury

Pulmonary fibrosis is the result of dysfunctional repair after lung tissue injury, characterized by fibroblast proliferation and massive extracellular matrix aggregation. Once fibrotic lesions develop, effective treatment is difficult, with few drugs currently available. Here, we identified a short cyclic decapeptide RL-RF10 derived from frog skin secretions as a potential novel lead molecule for the amelioration of pulmonary fibrosis. In vivo experiments indicated that RL-RF10 treatment ameliorated lung histopathological damage and fibrogenesis after paraquat (PQ) induction in a concentration-dependent manner. On day 7, bronchoalveolar lavage fluid assays performed on mice showed that RL-RF10 exerted anti-inflammatory effects by decreasing the expression of inflammation-related factors, including transforming growth factor-β1 (TGF-β1) and tumor necrosis factor-α, in lung tissue. In addition, RL-RF10 down-regulated the levels of collagen I, collagen III, and vimentin, while increasing the expression of E-cadherin to inhibit epithelial-mesenchymal transition. Further research demonstrated that the SMAD2/3 signaling pathway, which is strongly linked to TGF-β1, played a critical function in enhancing the pulmonary fibrosis relief achieved by RL-RF10. Both in vivo and in vitro assays showed that RL-RF10 treatment led to a significant reduction in the phosphorylation levels of SMAD2 and SMAD3 following PQ induction. Overall, we investigated the protective effects and underlying mechanisms of the RL-RF10 peptide against pulmonary fibrosis and demonstrated its potential as a novel therapeutic drug candidate for the treatment of pulmonary fibrotic diseases.

Peptide RL-QN15 promotes wound healing of diabetic foot ulcers through p38 mitogen-activated protein kinase and smad3/miR-4482-3p/vascular endothelial growth factor B axis

Background

Wound management of diabetic foot ulcers (DFUs) is a complex and challenging task, and existing strategies fail to meet clinical needs. Therefore, it is important to develop novel drug candidates and discover new therapeutic targets. However, reports on peptides as molecular probes for resolving issues related to DFUs remain rare. This study utilized peptide RL-QN15 as an exogenous molecular probe to investigate the underlying mechanism of endogenous non-coding RNA in DFU wound healing. The aim was to generate novel insights for the clinical management of DFUs and identify potential drug targets.

Methods

We investigated the wound-healing efficiency of peptide RL-QN15 under diabetic conditions using in vitro and in vivo experimental models. RNA sequencing, in vitro transfection, quantitative real-time polymerase chain reaction, western blotting, dual luciferase reporter gene detection, in vitro cell scratches, and cell proliferation and migration assays were performed to explore the potential mechanism underlying the promoting effects of RL-QN15 on DFU repair.

Results

Peptide RL-QN15 enhanced the migration and proliferation of human immortalized keratinocytes (HaCaT cells) in a high-glucose environment and accelerated wound healing in a DFU rat model. Based on results from RNA sequencing, we defined a new microRNA (miR-4482-3p) related to the promotion of wound healing. The bioactivity of miR-4482-3p was verified by inhibiting and overexpressing miR-4482-3p. Inhibition of miR-4482-3p enhanced the migration and proliferation ability of HaCaT cells as well as the expression of vascular endothelial growth factor B (VEGFB). RL-QN15 also promoted the migration and proliferation ability of HaCaT cells, and VEGFB expression was mediated via inhibition of miR-4482-3p expression by the p38 mitogen-activated protein kinase (p38MAPK) and smad3 signaling pathways.

Conclusions

RL-QN15 is an effective molecule for the treatment of DFUs, with the underlying mechanism related to the inhibition of miR-4482-3p expression via the p38MAPK and smad3 signaling pathways, ultimately promoting re-epithelialization, angiogenesis and wound healing. This study provides a theoretical basis for the clinical application of RL-QN15 as a molecular probe in promoting DFU wound healing.

Kinsenoside alleviates oxidative stress-induced blood-brain barrier dysfunction via promoting Nrf2/HO-1 pathway in ischemic stroke

An ischemic stroke usually causes blood-brain barrier (BBB) damage and excessive oxidative stress (OS) levels. Kinsenoside (KD), a major effective compound extracted in Chinese herbal medicine Anoectochilus roxburghii (Orchidaceae), has anti-OS effects. The present study focused on exploring KD's protection against OS-mediated cerebral endothelial cell damage and BBB damage within the mouse model. Intracerebroventricular administration of KD upon reperfusion after 1 h ischemia decreased infarct volumes, neurological deficit, brain edema, neuronal loss, and apoptosis 72 h post-ischemic stroke. KD improved BBB structure and function, as evidenced by a lower 18F-fluorodeoxyglucose pass rate of the BBB and upregulation of tight junction (TJ) proteins such as occludin, claudin-5, and zonula occludens-1 (ZO-1). KD protected bEnd.3 endothelial cells from oxygen and glucose deprivation/reoxygenation (OGD/R) injury in an in-vitro study. Meanwhile, OGD/R reduced transepithelial electronic resistance, whereas KD significantly increased TJ protein levels. Furthermore, based on in-vivo and in-vitro research, KD alleviated OS in endothelial cells, which is related to nuclear factor, erythroid 2 like 2 (Nrf2) nuclear translocation as well as Nrf2/haem oxygenase 1 signaling protein stimulation. Our findings demonstrated that KD might serve as a potential compound for treating ischemic stroke involving antioxidant mechanisms.

A short peptide exerts neuroprotective effects on cerebral ischemia-reperfusion injury by reducing inflammation via the miR-6328/IKKβ/NF-κB axis

BACKGROUND

Despite considerable efforts, ischemic stroke (IS) remains a challenging clinical problem. Therefore, the discovery of effective therapeutic and targeted drugs based on the underlying molecular mechanism is crucial for effective IS treatment.

METHODS

A cDNA-encoding peptide was cloned from RNA extracted from Rana limnocharis skin, and the mature amino acid sequence was predicted and synthesized. Hemolysis and acute toxicity of the peptide were tested. Furthermore, its neuroprotective properties were evaluated using a middle cerebral artery occlusion/reperfusion (MCAO/R) model in rats and an oxygen-glucose deprivation/reperfusion (OGD/R) model in neuron-like PC12 cells. The underlying molecular mechanisms were explored using microRNA (miRNA) sequencing, quantitative real-time polymerase chain reaction, dual-luciferase reporter gene assay, and western blotting.

RESULTS

A new peptide (NP1) with an amino acid sequence of 'FLPAAICLVIKTC' was identified. NP1 showed no obvious toxicities in vivo and in vitro and was able to cross the blood-brain barrier. Intraperitoneal administration of NP1 (10 nmol/kg) effectively reduced the volume of cerebral infarction and relieved neurological dysfunction in MCAO/R model rats. Moreover, NP1 significantly alleviated the decrease in viability and increase in apoptosis of neuron-like PC12 cells induced by OGD/R. NP1 effectively suppressed inflammation by reducing interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) levels in vitro and in vivo. Furthermore, NP1 up-regulated the expression of miR-6328, which, in turn, down-regulated kappa B kinase β (IKKβ). IKKβ reduced the phosphorylation of nuclear factor-kappa B p65 (NF-κB p65) and inhibitor of NF-κB (I-κB), thereby inhibiting activation of the NF-κB pathway.

CONCLUSIONS

The newly discovered non-toxic peptide NP1 ('FLPAAICLVIKTC') exerted neuroprotective effects on cerebral ischemia-reperfusion injury by reducing inflammation via the miR-6328/IKKβ/NF-κB axis. Our findings not only provide an exogenous peptide drug candidate and endogenous small nucleic acid drug candidate but also a new drug target for the treatment of IS. This study highlights the importance of peptides in the development of new drugs, elucidation of pathological mechanisms, and discovery of new drug targets.

OL-FS13 Alleviates Cerebral Ischemia-reperfusion Injury by Inhibiting miR-21-3p Expression

BACKGROUND

OL-FS13, a neuroprotective peptide derived from Odorrana livida, can alleviate cerebral ischemia-reperfusion (CI/R) injury, although the specific underlying mechanism remains to be further explored.

OBJECTIVE

The effect of miR-21-3p on the neural-protective effects of OL-FS13 was examined.

METHODS

In this study, the multiple genome sequencing analysis, double luciferase experiment, RT-qPCR, and Western blotting were used to explore the mechanism of OL-FS13.

RESULTS

Showed that over-expression of miR-21-3p against the protective effects of OL-FS13 on oxygen- glucose deprivation/re-oxygenation (OGD/R)-damaged pheochromocytoma (PC12) cells and in CI/R-injured rats. miR-21-3p was then found to target calcium/calmodulin-dependent protein kinase 2 (CAMKK2), and its overexpression inhibited the expression of CAMKK2 and phosphorylation of its downstream adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), thereby inhibiting the therapeutic effects of OL-FS13 on OGD/R and CI/R. Inhibition of CAMKK2 also antagonized up-regulated of nuclear factor erythroid 2-related factor 2 (Nrf-2) by OL-FS13, thereby abolishing the antioxidant activity of the peptide.

CONCLUSION

Our results showed that OL-FS13 alleviated OGD/R and CI/R by inhibiting miR-21-3p to activate the CAMKK2/AMPK/Nrf-2 axis.