Cellular functions of heat shock protein 20 (HSPB6) in cancer: A review.

Heat shock proteins (HSP) are a large family of peptide proteins that are widely found in cells. Studies have shown that the expression and function of HSPs in cells are very complex, and they can participate in cellular physiological and pathological processes through multiple pathways. Multiple heat shock proteins are associated with cancer cell growth, proliferation, metastasis, and resistance to anticancer drugs, and they play a key role in cancer development by ensuring the correct folding or degradation of proteins in cancer cells. As research hotspots, HSP90, HSP70 and HSP27 have been extensively studied in cancer so far. However, HSP20, also referred to as HSPB6, as a member of the small heat shock protein family, has been shown to play an important role in the cardiovascular system, but little research has been conducted on HSP20 in cancer. This review summarizes the current cellular functions of HSP20 in different cancer types, as well as its effects on cancer proliferation, progression, prognosis, and its other functions in cancer, to illustrate the close association between HSP20 and cancer. We show that, unlike most HSPs, HSP20 mainly plays an active anticancer role in cancer development, which is expected to provide new ideas and help for cancer diagnosis and treatment and research.

Proteomics reveals the protective mechanism of salvianolate injection on early hyperacute myocardial infarction / 药学学报

The hyperacute stage of myocardial infarction refers to a period of time within 30 minutes after the occurrence of myocardial infarction, when the symptoms are not obvious and the diagnosis is difficult, and the related pathophysiological mechanism has received less attention. In this study, proteomics was used to investigate the pathological changes in the early hyperacute phase of myocardial infarction, aiming to provide experimental evidence for pathological mechanism of myocardial infarction hyperacute stage. Meanwhile, the intervention effect and related mechanism of salvianolate injection were discussed based on heat shock protein B6 (HSPB6), aiming to benefit the clinical rational use of salvianolate injection. The protein expression changes before and after myocardial infarction model establishment were detected by label-free proteomics via mass spectrometry and analyzed by bioinformatics method. Then the binding effect of salvianolate injection on the commonly differential protein HSPB6 was evaluated by molecular docking technology, which was finally verified by animal experiments. All animal experimental protocols were approved by the Ethics Committee of Xiyuan Hosptial (2022XLC041). The results of this study showed that a total of 2 166 proteins were quantified by lable-free proteomics, of which 194 shared differential proteins were involved in myocardial injury and body regulation in the hyperacute phase of myocardial infarction, mainly involving molecular functions such as protein homodimerization activity, oxygen binding and transport, and serine endopeptidase inhibitor activity. Among them, HSPB6 protein is involved in the regulation of myocardial function. Molecular docking results indicated that magnesium salvianolate acetate, which is the main component of salvianolate injection, had the lowest binding energy with HSPB6 protein: -14.53 kcal·mol-1. Animal experiments showed that compared with the Sham group, the model group had significantly lower ejection fraction (EF) and fractional shortening (FS) (P < 0.001), cardiac blood perfusion decreased significantly (P < 0.001). There were obvious pathological changes such as myocardial fiber disorder, cardiomyocyte edema and interstitial small blood vessel congestion; the injury of cardiac function of rats in the administration group was attenuated, and the FS of rats in the low-dose group was significantly improved (P < 0.05), the pathological injury of myocardial tissue was markedly mitigated, and the expression of HSPB6 protein was up-regulated to varying degrees (P < 0.01, P < 0.001). In conclusion, salvianolate injection could be able to improve the cardiac function and pathological morphology of rats in the early hyperacute stage of myocardial infarction, and its mechanism may be related to the promotion of expression of HSPB6.

Genetic polymorphism in HSPB6 gene and their association with heat tolerance traits in Indian Karan Fries (Bos taurus x Bos indicus) cattle.

Heat shock proteins (HSPs) act as a chaperone activity ensuring the folding, unfolding, and refolding of denatured proteins, which help in a protective role during thermal stress in dairy cattle. This study aimed to detect genetic variations of the HSPB6 gene and to determine their association with heat tolerance traits in Karan Fries cattle. Five single nucleotide polymorphisms (SNPs) (SNP 1-5) were reported in the Karan Fries cattle, which included three transitions viz. SNP1-g.161G > A, SNP2-g.436G > A, and SNP4-g.2152A > G and two transversions viz. SNP3-g.1743C > G, SNP5-g.2417A > T. The association analysis revealed that the three SNPs loci i.e., SNP1-g.161G > A, SNP2-g.436G > A, and SNP3-g.1743C > G were significantly (p < 0.01) associated with the respiration rate (RR) and rectal temperature (RT) (°C) traits. Furthermore, in the case of heat tolerance coefficient (HTC) trait was found significantly associated (p < 0.01) with SNPs loci i.e., SNP1-g.161G > A, SNP2-g.436G > A, and SNP3-g.1743C > G. The Hap 4 (GACAT) was found to more adaptable than cattle of other haplotypes as reflected by lower values of RR, RT and HTC. This study provides the first association analyses between the SNPs and haplotypes of HSPB6 gene and heat tolerance traits in Karan Fries cattle, which could be used as effective SNP markers in genetic selection for heat tolerance in cattle breeding program.

Overexpressed HspB6 Underlines a Novel Inhibitory Role in Kainic Acid-Induced Epileptic Seizure in Rats by Activating the cAMP-PKA Pathway.

Epilepsy is a commonly occurring neurological disease that has a large impact on the patient's daily life. Phosphorylation of heat shock protein B6 (HspB6) has been reported to protect the central nervous system. In this investigation, we explored whether HspB6 played a positive effect on epilepsy with the involvement of the cyclic adenosine monophosphate-protein kinase A (cAMP-PKA) pathway. The epileptic seizure was induced in rats by intraperitoneal injection of kainic acid (KA). The extent of HspB6 phosphorylation and expressions of HspB6, PKA, and inflammatory factors TNF-α, IL-1ß, and IL-6 were quantified along with neuronal apoptosis. To further understand the regulatory mechanism of the HspB6 in the hippocampus, we altered the expression and the extent of HspB6 phosphorylation to see whether the cAMP-PKA pathway was inactivated or not in hippocampal neurons of rats post KA. Results showed that HspB6 was poorly expressed, resulting in the inactivation of the cAMP-PKA pathway in rats post KA, as well as an aggravated inflammatory response and hippocampal neuronal apoptosis. HspB6 overexpression and the cAMP-PKA pathway activation decreased the expression of inflammatory factors and inhibited hippocampal neuronal apoptosis. Additionally, HspB6 phosphorylation further augments the inhibitory effects of HspB6 on the inflammatory response and hippocampal neuronal apoptosis. The cAMP-PKA pathway activation was found to result in increased HspB6 phosphorylation. HspB6 decreased apoptosis signal-regulating kinase 1 (ASK1) expression to inhibit inflammatory response and hippocampal neuronal apoptosis. Collectively, our findings demonstrate that activation of the cAMP-PKA pathway induces overexpression and partial phosphorylation of HspB6 lead to the inhibition of ASK1 expression. This in turn protects rats against epilepsy and provides a potential approach to prevent the onset of epileptic seizure in a clinical setting.

The effect and mechanism of neutralizing heat shock protein B6 antibody on tube formation of human choroidal endothelial cell / 中华实验眼科杂志

Background The proliferation and migration of vascular endothelial cells is a primary link during angiogenesis.Studies showed that heat shock protein B6 (HspB6) promotes the secretion of multiple angiogenesis-related factors and therefore leads to neovascularization.Understanding the effects of neutralizing HspB6 antibody on the biological behavior of human choroidal vascular endothelial cells has an important significance in the target treatment of choroidal neovacularization diseases.Objective This study was to address the role and mechanism of neutralizing HspB6 antibody in tube formation of human choroidal vascular endothelial cells.Methods Human choroidal vascular endothelial cell line was normally cultured and harvested for total RNA extraction.Expressions of HspB6 mRNA and protein in human choroidal vascular endothelial cells were detected by reverse transcription PCR (RT-PCR) and flow cytometry (FCM).The cells were seeded on 96-well plate covered with matrigel at the density of 2×104/hole.Then the neutralizing HspB6 antibody at the concentration of 100 μg/Land 500 μg/L was added into the medium respectively,and the control cells were set without the addition of HspB6 antibody.The number of capillary tubes was calculated 12 hours after culture by three-dimensional matrigel assay.In addition,0,50,100,500 μg/L of neutralizing HspB6 antibody were added into the cell medium separately for 24hours,cell counting kit-8 (CCK-8) method was employed to assay the inhibitory rate(IR) of the cells.Transwell test was used to count the cell number across chamber membrane for the evaluation of migration ability of the cells.The apoptosis of the cells was assayed by FCM.Results Both HspB6 mRNA and protein were expressed on human choroidal vascular endothelial cells.The number of capillary tube formation of human choroidal vascular endothelial cells was (67.25±5.75),(60.39±6.41) and (39.76±10.73) /field in the 0,100 and 500 μg/L neutralizing HspB6 antibody groups,with significant difference among them (F =10.210,P =0.012),and the tube number was significantly less in the 500 μg/L neutralizing HspB6 antibody group compared with 0 μg/L neutralizing HspB6 group (P =0.005).The IR of neutralizing HspB6 antibody to the cellular proliferation and migration was enhanced with the increases of concentration and time lapse(Fconcentration =7.485,P =0.002 ; Ftime =16.684,P =0.001).The number of the cells through Transwell chamber membrane was 14.0 ± 2.5,11.1 ± 0.8,6.6 ± 0.1,6.7 ± 0.2 in the 0,50,100,500 μg/L neutralizing HspB6 antibody group respectively,and that in the 100 μg/L and 500 μg/L neutralizing HspB6 antibody group was lessened in comparison with the 0 μg/L neutralizing HspB6 antibody group(both at P=0.000).The apoptosis rate of the cells was (22.73 ± 2.53)％ in the neutralizing HspB6 antibody group,which was significantly lower than (13.33±2.08) ％ of the control group (t=4.967,P=0.008).Conclusions Neutralizing HspB6 antibody inhibits capillary tube formation of human choroidal endothelial cells in vitro in dose-and timedependent manner,probably through suppressing the proliferation and migration and promoting the apoptosis of choroidal endothelial cells.