Impaired Heat Shock Protein Expression in Activated T Cells in B-Cell Lymphoma

HSP60 controls mitochondrial ATP generation for optimal virus-specific IL-21-producing CD4 and cytotoxic CD8 memory T cell responses

We have shown that virus-specific CD4 and CD8 memory T cells (TM) induce autophagy after T cell receptor (TCR) engagement to provide free glutamine and fatty acids, including in people living with HIV-1 (PLWH). These nutrients fuel mitochondrial ATP generation through glutaminolysis and fatty acid oxidation (FAO) pathways, to fulfill the bioenergetic demands for optimal IL-21 and cytotoxic molecule production in CD4 and CD8 cells, respectively. Here, we expand our knowledge on how the metabolic events that occur in the mitochondria of virus-specific TM down-stream of the autophagy are regulated. We show that HSP60 chaperone positively regulates the protein levels for multiple glutaminolysis- and FAO-related enzymes, thereby actively fueling the levels of cellular alpha-ketoglutarate (αKG) and related mitochondrial ATP-dependent antiviral T cell immunity in both CD4 and CD8 TM. Finally, we provide a way to rescue defective ATP generation in mitochondria and dependent effector functions in virus-specific TM including anti-HIV-1 protective responses, when HSP60 expression is impaired after TCR engagement in patients, in the form of dimethyl 2-oxoglutarate (DMKG) supplementation.

HSP90 multi-functionality in cancer

The 90-kDa heat shock proteins (HSP90s) are molecular chaperones essential for folding, unfolding, degradation and activity of a wide range of client proteins. HSP90s and their cognate co-chaperones are subject to various post-translational modifications, functional consequences of which are not fully understood in cancer. Intracellular and extracellular HSP90 family members (HSP90α, HSP90β, GRP94 and TRAP1) promote cancer by sustaining various hallmarks of cancer, including cell death resistance, replicative immortality, tumor immunity, angiogenesis, invasion and metastasis. Given the importance of HSP90 in tumor progression, various inhibitors and HSP90-based vaccines were developed for the treatment of cancer. Further understanding of HSP90 functions in cancer may provide new opportunities and novel therapeutic strategies for the treatment of cancer.

Heat shock protein 90α reduces CD8+ T cell exhaustion in acute lung injury induced by lipopolysaccharide

CD8+ T-cell exhaustion is a promising prognostic indicator of sepsis-induced acute respiratory distress syndrome (ARDS). Patients with sepsis-related ARDS had reduced levels of HSP90AA1. However, whether the changes in CD8+ T cells were related to HSP90α, encoded by the HSP90AA1 gene, was unclear. This study aimed to examine the regulatory mechanism of HSP90α and its impact on CD8+ T-cell exhaustion in lipopolysaccharide (LPS)-induced acute lung injury (ALI). In this study, by conducting a mouse model of ALI, we found that one week after LPS-induced ALI, CD8+ T cells showed exhaustion characteristics. At this time, proliferation and cytokine release in CD8+ T cells were reduced. The inhibitory costimulatory factors PD-1 and Tim-3, on the other hand, were enhanced. Meanwhile, the expression of HSP90α and STAT1 decreased significantly. The in vitro studies showed that HSP90α stimulation or inhibition affected the CD8+ T-cell exhaustion phenotype. Interference with STAT1 reduced the expression of HSP90α and impaired its regulation of CD8+ T cells. The Co-Immunoprecipitation results indicated that HSP90α can directly or indirectly bind to TOX to regulate TOX expression and downstream signal transduction. In summary, by inhibiting TOX-mediated exhaustion signaling pathways, HSP90α inhibited CD8+ T-cell exhaustion in ALI. The participation of STAT1 in the regulation of HSP90α was required.

Effect of acupuncture therapy on vaccine-induced immune response in d-galactose-induced aging rats

Objective

This study aimed to explore whether acupuncture and moxibustion can enhance the immune response by increasing the expression of the endogenous adjuvant HSP70 mRNA.

Method

Forty Wistar rats were divided into four groups: model immune acupuncture group (A), model immune control group (B), normal immune acupuncture group (C), and normal immune control group (D). Model immune groups A and B were induced by injecting d-galactose for 6 weeks. Rats in groups A and C were then treated with low-frequency electroacupuncture (EA) at Zusanli (ST36), Guanyuan (CV4), and Baihui (GV20) and moxibustion for 3 weeks. Subsequently, all rats were observed for 2 more weeks. At the 12th week, diphtheria antitoxin titers were determined using the Vero cell trace neutralization method, CD4+T/CD8+T cell ratios in peripheral blood were examined by flow cytometry, and the relative expression of spleen cell HSP70 mRNA was measured by RT-PCR.

Results

Compared with the normal immune control, the diphtheria antitoxin titer, CD4+T/CD8+T cell ratio, and expression of spleen cell HSP70 mRNA significantly decreased in the model immune control group (P < 0.01). However, the model immune acupuncture group showed a significant increase in antitoxin titer (P < 0.01) and elevated CD4+T/CD8+T cell ratio and HSP70 mRNA expression (P < 0.05) after EA and moxibustion intervention.

Conclusion

Acupuncture and moxibustion may enhance the humoral immune response (diphtheria antitoxin titer) and cellular immune response (peripheral blood CD4+T/CD8+T cell ratio) by increasing the expression of the endogenous adjuvant HSP70 mRNA, suggesting that acupuncture may serve as a new vaccine adjuvant.

Themis controls T cell activation, effector functions, and metabolism of peripheral CD8+ T cells

Themis is important in regulating positive selection of thymocytes during T cell development, but its role in peripheral T cells is less understood. Here, we investigated T cell activation and its sequelae using a tamoxifen-mediated, acute Themis deletion mouse model. We find that proliferation, effector functions including anti-tumor killing, and up-regulation of energy metabolism are severely compromised. This study reveals the phenomenon of peripheral adaptation to loss of Themis, by demonstrating direct TCR-induced defects after acute deletion of Themis that were not evident in peripheral T cells chronically deprived of Themis in dLck-Cre deletion model. Peripheral adaptation to long-term loss was compared using chronic versus acute tamoxifen-mediated deletion and with the (chronic) dLck-Cre deletion model. We found that upon chronic tamoxifen-mediated Themis deletion, there was modulation in the gene expression profile for both TCR and cytokine signaling pathways. This profile overlapped with (chronic) dLck-Cre deletion model. Hence, we found that peripheral adaptation induced changes to both TCR and cytokine signaling modules. Our data highlight the importance of Themis in the activation of CD8+ T cells.