CircOAS3 Regulates Keratinocyte Proliferation and Psoriatic Inflammation by Interacting with Hsc70 via the JNK/STAT3/NF-κB Signaling Pathway.

Psoriasis is a chronic inflammatory disease of the skin with a very complex pathogenesis. Circular RNAs (circRNAs) play important regulatory roles in many diseases, including psoriasis. In this study, we found that circOAS3 expression was significantly upregulated in both psoriatic tissues and M5-induced keratinocytes. Silencing circOAS3 in HaCaT and Ker-CT cells inhibited their viability, promoted apoptosis, and blocked the cell cycle from the G1 to the S phase. RNA pull-down and RNA immunoprecipitation (RIP) analyses led to the identification of a direct interaction between circOAS3 and heat shock cognate protein 70 (Hsc70). Silencing circOAS3 expression negatively influenced Hsc70 protein expression but not mRNA expression. circOAS3 knockdown suppressed the activation of the JNK/STAT3/NF-κB signaling pathway. circOAS3 or Hsc70 silencing led to downregulated protein IL-6 expression, thus reducing psoriatic inflammation in vitro. In conclusion, the interaction between circOAS3 and Hsc70 mediates the proliferation and psoriatic inflammation of HaCaT and Ker-CT cells through the JNK/STAT3/NF-κB signaling pathway, suggesting that circOAS3 or Hsc70 may be a promising therapeutic target for psoriasis.

Exogenous protein Hsp70/Hsc70 can penetrate into brain structures and attenuate the severity of chemically-induced seizures.

Heat shock protein 70 kDa (Hsp70) possesses a remarkable neuroprotective activity and the results of recent studies demonstrated its efficacy in the attenuation of epileptic seizures. The aim of this study was to explore the effects of a pure Hsp70/Hsc70 preparation delivered to the brain regions involved in generalized seizures induced in rats by intracerebroventricular microinjections of NMDA or systemic injections of pentylenetetrazole. Purified Hsp70/Hsc70 was administered (intracerebroventricular) 2 h before the induction of seizures. Compared to the vehicle-treated control animals, Hsp70/Hsc70-pretreated rats demonstrated reduced severity of NMDA- and pentylenetetrazole-induced seizures. To identify the brain structures potentially implicated in the Hsp70/Hsc70-mediated anticonvulsant effect, we analysed the localization of a fluorescently-labelled chaperone in the brain. Labelled Hsp70/Hsc70 was found in neurons and terminals of the limbic seizure complex of the brain and was co-localized in these regions with NMDA receptors, synaptophysin and the GABA-synthesizing enzyme, L-glutamic acid decarboxylase 67. An immunoprecipitation assay confirmed interactions between Hsp70 and both synaptophysin and L-glutamic acid decarboxylase 67 in brain tissue. We suggest that the anticonvulsant effect of exogenous Hsp70/Hsc70 is not only based on its protective capacity but is also related to its ability to modulate GABA neurotransmission, which in turn contributes to the maintenance of the excitatory-inhibitory balance of the CNS.

Both CD4+ and CD8+ T cell epitopes fused to heat shock cognate protein 70 (hsc70) can function to eradicate tumors.

Vaccination with heat shock proteins (HSP) protects mice from challenge with the tumor from which the HSP were isolated. The antigenicity of HSP vaccination is thought to result from HSP-associated endogenous major histocompatibility complex class I peptides or their precursors. The vaccination effect can be achieved in an adjuvant-free manner and is mediated by CD8(+) T cells, indicating that HSP can act as a natural adjuvant and cross-prime T cells in vivo. We previously devised a recombinant vaccine composed of a CD8(+) T cell epitope fused to the carboxyl-terminus of hsc70 and demonstrated efficient generation of antigen-specific cytotoxic T lymphocyte (CTL) after vaccination with a few micrograms of the hsc70-CTL epitope fusion protein. The present study aimed to determine if the fusion protein vaccine could control tumor growth in vivo and whether simultaneous fusion of a CD4(+) T cell epitope to the amino terminus of the hsc70-CTL epitope would be a more potent vaccine compared to the CTL epitope alone. Ovalbumin (OVA)-derived 8 mer peptide, OVA(257-264), and 16mer peptide, OVA(265-280), were used as CD8(+) and CD4(+) T cell epitopes, respectively. Vaccination with hsc70-OVA(257-264) generated peptide specific CTL more effectively than a peptide plus incomplete Freund's adjuvant combination, and suppressed growth of OVA expressing EL4 (E.G7) and B16 melanoma tumor cells. Addition of OVA(265-280) to the amino-terminus of hsc70-OVA(257-264) (OVA(265-280)-hsc70-OVA(257-264)) enhanced the generation of the OVA(257-264)-specific CTL population, leading to better eradication of MO5 lung metastasis compared to hsc70-OVA(257-264). Our results suggest that fusion of both CD4(+) and CD8(+) T cell epitopes to hsc70 enhances tumor immunity beyond the effect of the CD8(+) T cell epitope alone.