Scorpion venom peptide HsTx2 suppressed PTZ-induced seizures in mice via the circ_0001293/miR-8114/TGF-ß2 axis.

BACKGROUND: Due to the complexity of the mechanisms involved in epileptogenesis, the available antiseizure drugs (ASDs) do not meet clinical needs; hence, both the discovery of new ASDs and the elucidation of novel molecular mechanisms are very important. METHODS: BALB/c mice were utilized to establish an epilepsy model induced by pentylenetetrazol (PTZ) administration. The peptide HsTx2 was administered for treatment. Primary astrocyte culture, immunofluorescence staining, RNA sequencing, identification and quantification of mouse circRNAs, cell transfection, bioinformatics and luciferase reporter analyses, enzyme-linked immunosorbent assay, RNA extraction and reverse transcription-quantitative PCR, Western blot and cell viability assays were used to explore the potential mechanism of HsTx2 via the circ_0001293/miR-8114/TGF-ß2 axis. RESULTS: The scorpion venom peptide HsTx2 showed an anti-epilepsy effect, reduced the inflammatory response, and improved the circular RNA circ_0001293 expression decrease caused by PTZ in the mouse brain. Mechanistically, in astrocytes, circ_0001293 acted as a sponge of endogenous microRNA-8114 (miR-8114), which targets transforming growth factor-beta 2 (TGF-ß2). The knockdown of circ_0001293, overexpression of miR-8114, and downregulation of TGF-ß2 all reversed the anti-inflammatory effects and the influence of HsTx2 on the MAPK and NF-κB signaling pathways in astrocytes. Moreover, both circ_0001293 knockdown and miR-8114 overexpression reversed the beneficial effects of HsTx2 on inflammation, epilepsy progression, and the MAPK and NF-κB signaling pathways in vivo. CONCLUSIONS: HsTx2 suppressed PTZ-induced epilepsy by ameliorating inflammation in astrocytes via the circ_0001293/miR-8114/TGF-ß2 axis. Our results emphasized that the use of exogenous peptide molecular probes as a novel type of ASD, as well as to explore the novel endogenous noncoding RNA-mediated mechanisms of epilepsy, might be a promising research area.

Amphibian-derived peptide homodimer OA-GL17d promotes skin wound regeneration through the miR-663a/TGF-ß1/Smad axis.

Background: Amphibian-derived peptides exhibit considerable potential in the discovery and development of new therapeutic interventions for clinically challenging chronic skin wounds. MicroRNAs (miRNAs) are also considered promising targets for the development of effective therapies against skin wounds. However, further research in this field is anticipated. This study aims to identify and provide a new peptide drug candidate, as well as to explore the underlying miRNA mechanisms and possible miRNA drug target for skin wound healing. Methods: A combination of Edman degradation, mass spectrometry and cDNA cloning were adopted to determine the amino acid sequence of a peptide that was fractionated from the secretion of Odorrana andersonii frog skin using gel-filtration and reversed-phase high-performance liquid chromatography. The toxicity of the peptide was evaluated by Calcein-AM/propidium iodide (PI) double staining against human keratinocytes (HaCaT cells), hemolytic activity against mice blood cells and acute toxicity against mice. The stability of the peptide in plasma was also evaluated. The prohealing potency of the peptide was determined by MTS, scratch healing and a Transwell experiment against HaCaT cells, full-thickness injury wounds and scald wounds in the dorsal skin of mice. miRNA transcriptome sequencing analysis, enzyme-linked immunosorbent assay, real-time polymerase chain reaction and western blotting were performed to explore the molecular mechanisms. Results: A novel peptide homodimer (named OA-GL17d) that contains a disulfide bond between the 16th cysteine residue of the peptide monomer and the sequence 'GLFKWHPRCGEEQSMWT' was identified. Analysis showed that OA-GL17d exhibited no hemolytic activity or acute toxicity, but effectively promoted keratinocyte proliferation and migration and strongly stimulated the repair of full-thickness injury wounds and scald wounds in the dorsal skin of mice. Mechanistically, OA-GL17d decreased the level of miR-663a to increase the level of transforming growth factor-ß1 (TGF-ß1) and activate the subsequent TGF-ß1/Smad signaling pathway, thereby resulting in accelerated skin wound re-epithelialization and granular tissue formation. Conclusions: Our results suggest that OA-GL17d is a new peptide drug candidate for skin wound repair. This study emphasizes the importance of exogenous peptides as molecular probes for exploring competing endogenous RNA mechanisms and indicates that miR-663a may be an effective target for promoting skin repair.

Peptide OM-LV20 promotes structural and functional recovery of spinal cord injury in rats.

At present, there are no satisfactory therapeutic drugs for the functional recovery of spinal cord injury (SCI). We previously identified a novel peptide (OM-LV20) that accelerated the regeneration of injured skin tissues of mice and exerts neuroprotective effects against cerebral ischemia/reperfusion injury in rats. Here, the intraperitoneal injection of OM-LV20 (1 µg/kg) markedly improved motor function recovery in the hind limbs of rats with traumatic SCI, and further enhanced spinal cord repair. Administration of OM-LV20 increased the number of surviving neuron bodies, as well as the expression levels of brain-derived neurotrophic factor (BDNF) and its receptor tyrosine receptor kinase B (TrkB). In the acute stage of SCI, OM-LV20 treatment also increased superoxide dismutase and glutathione content but decreased the levels of malonaldehyde and nitric oxide. Thus, OM-LV20 significantly promoted structural and functional recovery of SCI in adult rats by increasing neuronal survival and BDNF and TrkB expression, and thereby regulating the balance of oxidative stress. Based on our knowledge, this research is the first report on the effects of amphibian-derived peptide on the recovery of SCI and our results highlight the potential of peptide OM-LV20 administration in the acceleration of the recovery of SCI.

The beneficial roles of poisonous skin secretions in survival strategies of the odorous frog Odorrana andersonii.

The evolution of predatory, anti-predatory, and defensive strategies regarding environmental adaptation in animals is of significant research interest. In particular, amphibians, who represent a transition between aquatic and terrestrial vertebrates, play an important role in animal evolution. The bioactive skin secretions of amphibians are of specific interest due to their involvement in the crucial physiological functions of amphibian skin. We previously isolated and identified several bioactive peptides, including those showing antioxidant, antimicrobial, and wound-healing properties, from the skin secretions of the odorous frog species Odorrana andersonii. Currently, however, the biological significance of skin secretions in O. andersonii survival remains unclear. Here, we studied the biological significance of skin glands and secretions in regard to environmental adaptations of O. andersonii. Our research found that O. andersonii may secrete and excrete bioactive secretions through many glands (peptides and proteins as the main components in glands) distributed in the skin. The skin secretions not only displayed toxicity but also showed antioxidant, antibacterial, and repair promoting activities, suggesting that they play a protective role in O. andersonii when facing environmental threats. These bioactive skin secretions appear to act as a chemical survival strategy in O. andersonii, allowing the species to gain advantages in survival behavior.

Discovery of a novel rice-derived peptide with significant anti-gout potency.

As a metabolic disease, gout, which seriously affects the normal life of patients, has become increasingly common in modern society. However, the existing medicines cannot completely meet the clinical needs. In the current study, a novel short peptide (named rice-derived-peptide-2 (RDP2), AAAAGAMPK-NH2, 785.97 Da) was isolated and identified from water extract of shelled Oryza sativa fruits, without toxic side effects but excellent stability. Our results indicated that RDP2 (the minimum effective concentration is 5 µg kg-1) induced a significant reduction in serum uric acid levels in hyperuricemic mice via suppressing xanthine oxidase activity and urate transporter 1 expression, as well as alleviated renal damage through inhibiting the activation of NLRP3 inflammasome. In addition, RDP2 can also alleviate paw swelling and inflammatory reactions in mice after subcutaneous injection of monosodium urate crystals. As mentioned above, we obtained a novel peptide which could work through all stages of gout, not only reducing uric acid levels and renal damage in hyperuricemic mice, but also alleviating inflammatory responses associated with acute gout attack, and thus provided a new peptide molecular template for the development of anti-gout drugs.

Accelerated Wound Healing Induced by a Novel Amphibian Peptide (OA-FF10).

BACKGROUND: Despite the continued development of modern medicine, chronic wounds are still a critical issue in clinical treatment, placing a great physiological, psychological, and financial burden on patients. Researchers have investigated many methods to solve this problem, with bioactive peptides gaining increasing attention due to their considerable advantages and diverse functions, as well as low cost, simple storage, and easy transportation. METHODS: In this research, a novel peptide (named OA-FF10) was identified from the skin secretions of the odorous frog species Odorrana andersonii. The sequence of mature OA-FF10 was "FFTTSCRSGC", which was produced by the post-translational processing of a 61-residue prepropeptide. RESULTS: Similar to most frog peptides, OA-FF10 showed an intramolecular disulfide bridge at the C-terminus. OA-FF10 demonstrated no antibacterial, antioxidant, hemolytic, or acute toxic activity, but promoted wound healing and proliferation of human keratinocytes (HaCaT) both time- and dose-dependently. Furthermore, while OA-FF10 had no effect on wound healing of Human Skin Fibroblasts (HSF), it did accelerate healing in a full-thickness skin-wound mouse model. CONCLUSION: Our research revealed the strong wound-healing activity of OA-FF10 in vivo and in vitro, thus providing a new candidate for the development of novel wound-healing drugs.

New Rice-Derived Short Peptide Potently Alleviated Hyperuricemia Induced by Potassium Oxonate in Rats.

Gout that caused by hyperuricemia affects human health seriously and more efficient drugs are urgently required clinically. In this study, a novel peptide named RDP1 (AAAAGAKAR, 785.91 Da) was identified from the extract of shelled fruits of Oryza sativa. Our results demonstrated that RDP1 (the minimum effective concentration is 10 µg/kg) could significantly reduce the serum uric acid and creatinine and alleviate hyperuricemic nephropathy in rats by intragastric administration. RDP1 inhibited xanthine oxidase, which also was verified at the animal level. Results from molecular docking indicated that RDP1 can inhibit uric acid formation by occupying the binding site of xanthine oxidase to xanthine. Besides, RDP1 showed no toxicity on rats and was stable in several temperatures, demonstrating its advantages for transportation. This research was the first discovery of antihyperuricemic peptide from the shelled fruits of O. Sativa and provided a new candidate for the development of hypouricemic drugs.

OA-GL21, a novel bioactive peptide from Odorrana andersonii, accelerated the healing of skin wounds.

Nowadays, the number of chronic trauma cases caused by a variety of factors such as the world's population-ageing and chronic diseases is increasing steadily, and thus effective treatment for chronic wounds has become a severe clinical challenge, which also burdens the patient both physically and financially. Therefore, it is urgent to develop new drugs to accelerate the healing of wounds. Bioactive peptides, which are relatively low cost, easy to produce, store and transport, have become an excellent choice. In this research, we identified a novel peptide OA-GL21, with an amino acid sequence of 'GLLSGHYGRVVSTQSGHYGRG', from the skin secretions of Odorrana andersonii Our results showed that OA-GL21 exerted the ability to promote wound healing of human keratinocytes (HaCaT) and human fibroblasts in a dose- and time-denpendent manner. However, OA-GL21 had no significant effect on the proliferation of these two cells. Significantly, OA-GL21 showed obvious ability to promote wound healing in the full-thickness skin wound model in dose- and scar-free manners. Further studies showed that OA-GL21 had no direct antibacterial, hemolytic, and acute toxic activity; it had weak antioxidant activities but high stability. In conclusion, this research proved the promoting effects of OA-GL21 on cellular and animal wounds, and thus provided a new peptide template for the development of wound-repairing drugs.

Neural Stem Cell Transplantation Is Associated with Inhibition of Apoptosis, Bcl-xL Upregulation, and Recovery of Neurological Function in a Rat Model of Traumatic Brain Injury.

Traumatic brain injury (TBI) is a common disease that usually causes severe neurological damage, and current treatment is far from satisfactory. The neuroprotective effects of neural stem cell (NSC) transplantation in the injured nervous system have largely been known, but the underlying mechanisms remain unclear, and their limited sources impede their clinical application. Here, we established a rat model of TBI by dropping a weight onto the cortical motor area of the brain and explored the effect of engrafted NSCs (passage 3, derived from the hippocampus of embryonic 12- to 14-d green fluorescent protein transgenic mice) on TBI rats. Moreover, RT-PCR and Western blotting were employed to investigate the possible mechanism associated with NSC grafts. We found rats with TBI exhibited a severe motor and equilibrium dysfunction, while NSC transplantation could partly improve the motor function and significantly reduce cell apoptosis and increase B-cell lymphoma-extra large (Bcl-xL) expression at 7 d postoperation. However, other genes including Bax, B-cell lymphoma 2, Fas ligand, and caspase3 did not exhibit significant differences in expression. Moreover, to test whether Bcl-xL could be used as a therapeutic target, herpes simplex virus (HSV) 1 carrying Bcl-xL recombinant was constructed and injected into the pericontusional cortices. Bcl-xL overexpression not only resulted in a significant improvement in neurological function but also inhibits cell apoptosis, as compared with the TBI rats, and exhibits the same effects as the administration of NSC. The present study therefore indicated that NSC transplantation could promote the recovery of TBI rats in a manner similar to that of Bcl-xL overexpression. Therefore, Bcl-xL overexpression, to some extent, could be considered as a useful strategy to replace NSC grafting in the treatment of TBI in future clinical practices.

Principle of relative positioning of structures in the human body.

The arrangement of various biological structures should generally ensure the safety of crucial structures and increase their working efficiency; however, other principles governing the relative positions of structures in humans have not been reported. The present study therefore investigated other principles using nerves and their companion vessels in the human body as an example. Nerves and blood vessels usually travel together and in the most direct way towards their targets. Human embryology, histology, and gross anatomy suggest that there are many possible positions for these structures during development. However, for mechanical reasons, tougher or stronger structures should take priority. Nerves are tougher than most other structures, followed by arteries, veins, and lymphatic vessels. Nerves should therefore follow the most direct route, and be followed by the arteries, veins, and lymphatic vessels. This general principle should be applicable to all living things.

Roles of BDNF in spinal neuroplasticity in cats subjected to partial dorsal ganglionectomy.

This study investigated the role of brain-derived neurotrophic factor (BDNF) in neuroplasticity in cats subjected to the removal of dorsal root ganglia (DRG). Following partial ganglionectomy, the number of BDNF-positive varicosities from spared L6 DRG decreased significantly. This reduction was observed at 3 days post operation (dpo) in spinal lamina II of L3 and L5. Whereas the percentages of positive neurons for BDNF and its mRNA in spared L6 DRG at 10 dpo were significantly increased, and accumulated BDNF was seen on the DRG side of the ligated axons. Importantly, BDNF antibody neutralization in vivo results in a significant reduction in the number of varicosities in spinal lamina II, evidenced by BDNF and calcitonin gene-related peptide immunohistochemical staining. These findings suggested that peripheral-derived BDNF could play a critical role in spinal neuroplasticity in cats subjected to partial ganglionectomy. This may underlie the basis of molecular therapy depending on gene drug-like BDNF release.

[Study on the change of angiotensin II expression in rat lung exposure to acrolein].

OBJECTIVE: To investigate the changes of angiotensin II (Ang II) expression in a rat model of mucus hypersecretion induced by acrolein. METHODS: A rat model of mucous hypersecretion of airway was established by acrolein-inhalation. The AB/PAS stain was performed to evaluate the mucous secretion level. Immunohistochemistry and Western blot were employed to detect the expression of Ang II protein. RESULTS: Hypersecretion of mucus occurred at 3 weeks and peaked at 6 weeks post exposure (wpe) to acrolein. Increased immunostaining and protein level of Ang II were readily detected in rat lung at 3 wpe and enhanced at 6 wpe. CONCLUSION: The increase of Ang II expression, which associated to pulmonary mucus hypersecretion, might play a role in the lung injury induced by acrolein exposure.

[Effects of acrolein exposure on the expression of Muc5ac in the airway of rats].

OBJECTIVE: To explore the changes of Muc5ac expression in a rat model of mucus hypersecretion induced by acrolein. METHODS: The rat model of mucus hypersceretion was established by acrolein exposure. RT-PCR, ISH, immunohistochemistry and Western blot were employed to detect the mRNA and protein levels of Muc5ac in the rats airway. RESULTS: The expression of Muc5ac was detected in trachea and lung at 3 weeks post exposure (wpe) and the expression level was enhanced at 6 wpe. ISH confirmed that Muc5ac was synthesized endogenously. CONCLUSION: The pulmonary mucus hypersecretion is associated to the increase of intrinsic Muc5ac expression in the rat airway exposure to acrolein.

[Effects of enalapril on IL-1beta, IL-6 expression in rat lung exposure to acrolein].

OBJECTIVE: To investigate the effects of enalapril on the expressions of IL-1beta and IL-6 in the lung of rats treated with acrolein inhalation. METHODS: Inflammatory lung injury was induced by acrolein inhalation in rats. The rats were divided into natrium solution (NS) group, acrolein group, enalapril and acroclein (EA) group, enalapril and NS (EN) group. Lungs were harvested from the rats in each group at 1 week, 3 weeks, 6 weeks after the treatment of natrium solution, acrolein inhalation and/or enalapril. The mRNA and protein expressions of IL-1beta and IL-6 in the lung tissues were measured by RT-PCR, in situ hybridization, immunohistochemistry and Western blot. RESULTS: Increased immunostaining, protein level and mRNA expression of IL-1beta and IL-6 were found in rat lung at 3 weeks and reached to the peak at 6 weeks post exposure to acrolein. The administration of enalapril resulted in a significant downregulation of IL-1beta and IL-6 in both protein and gene level, accompany with the decrease of inflammation. CONCLUSION: Enalapril, as a ACE inhibitor, could protect the airway from inflammation injury in acrolein-treated rats via the down-regulation of IL-1beta and IL-6 expression.

Role of Neurotrophin 3 in spinal neuroplasticity in rats subjected to cord transection.

That neuroplasticity occurs in mammalian spinal cord is well known, though the underlying mechanism still awaits elucidation. This study evaluated the role of endogenous Neurotrophin-3 (NT-3) in the spinal neuroplasticity. Following cord transection at the junction between T9 and T10, the hindlimb locomotor functions of rats showed gradual but significant improvement from 7 to 28 days post-operation. Corresponding to this was a significant increase in the level of NT-3 in the cord segments caudal to injury site. Significantly, after NT-3-antibody administration, the spinal transected rats displayed poor hindlimb locomotor functions and a decrease in the number of neurons in spinal laminae VIII-IX. Whether NT-3-antibody was administered, corticospinal tract regeneration and somatosensory evoked potentials could not be detected. Our findings suggested that endogenous NT-3 could play an important role in spinal plasticity in adult spinal cords subjected to transection, possibly through a regulation of neuronal activity in the local circuitry.