Project description:To investigate the immediate effect of HSP60 dysfunction on mitochondrial functions, we induced the expression of a dominant-negative ATPase-deficient HSP60 mutant (HSP60-D423A) in HEK293 cells using tetracycline . Incorporation of HSP60-D423A subunits into HSP60 heptamer rings leads to dysfunction of the chaperonin complex. We titrated tetracycline levels to have a biologically relevant cellular model that can be monitored over time. Expression of the HSP60-D432A protein resulted in significantly reduced cell counts at 72 hours induction compared to uninduced and HSP60-WT co-expressing cells. To study the effects of onset of HSP60 deficiency, we monitored transcriptional changes using RNASeq.
Project description:To identify regulatory responses that could give clues as to the cause(s) of the growth arrest observed in E. coli cells expressing mutant Hsp60-(p.Val98Ile) and Hsp10 versus cells expressing wild type Hsp60 and Hsp10, we performed microarray analyses. We reasoned that the decreased chaperonin activity of the Hsp60-(p.Val98Ile) protein would greatly impair or abolish folding of E. coli proteins that depend on chaperonin assistance. The resulting decreased levels of various activities may cause compensatory up-regulation or deregulation of genes. The transcriptomes of cells shifted to expression of the arabinose-inducible chaperonin operon with either the Hsp60-(p.Val98Ile) mutant or the wild type Hsp60 from the second plasmid were compared. RNA samples from three independent cultures expressing the mutant or two independent cultures expressing wild type Hsp60 were pooled, respectively. Keywords: Comparison of cells expressing two different variants of Hsp60
Project description:To identify regulatory responses that could give clues as to the cause(s) of the growth arrest observed in E. coli cells expressing mutant Hsp60-(p.Val98Ile) and Hsp10 versus cells expressing wild type Hsp60 and Hsp10, we performed microarray analyses. We reasoned that the decreased chaperonin activity of the Hsp60-(p.Val98Ile) protein would greatly impair or abolish folding of E. coli proteins that depend on chaperonin assistance. The resulting decreased levels of various activities may cause compensatory up-regulation or deregulation of genes. The transcriptomes of cells shifted to expression of the arabinose-inducible chaperonin operon with either the Hsp60-(p.Val98Ile) mutant or the wild type Hsp60 from the second plasmid were compared. RNA samples from three independent cultures expressing the mutant or two independent cultures expressing wild type Hsp60 were pooled, respectively. Experiment Overall Design: B178 (groELS)-deleted cells double-transformed with two plasmids harboring an IPTG-inducible operon with wild type human Hsp60 and Hsp10 and a second plasmid harboring an arabinose inducible operon with either Hsp60-(p.Val98Ile) and Hsp10 (mutant cells) or wild type Hsp60 and Hsp10 (wild type cells) were grown in dYT medium (21) supplemented with kanamycin (10 mg/L), ampicillin (100 mg/L) and IPTG (0.1mM) at 30°C in a shaking water bath. At OD536 â?? 0.1 bacteria were harvested by centrifugation at ambient temperature, resuspended in fresh medium, and 0.2% arabinose was added. Growth was continued at 30°C. After 10 hours 3ml samples were withdrawn and RNA was isolated. Experiment Overall Design: Two independent transformant clones of the wild type cells and three of the mutant cells were grown in this way. The RNA preps from the 2 wild type and the three mutant cells, respectively, were pooled, cDNA was synthesized, labelled and subjected to Affymetrix arrays.
Project description:To investigate the immediate effect of HSP60 dysfunction on mitochondrial functions, we induced the expression of a dominant-negative ATPase-deficient HSP60 mutant (HSP60-D423A) in HEK293 cells using tetracycline . Incorporation of HSP60-D423A subunits into HSP60 heptamer rings leads to dysfunction of the chaperonin complex. We titrated tetracycline levels to have a biologically relevant cellular model that can be monitored over time. Expression of the HSP60-D432A protein resulted in significantly reduced cell counts at 72 hours induction compared to uninduced and HSP60-WT co-expressing cells. To study the effects of onset of HSP60 deficiency, we monitored the proteomics changes using TMT based proteomics.
Project description:Pro-inflammatory response of VSMCs is triggered by endothelial damage and a causative step for thrombosis and neointimal thickening in the arterial vessels. Therefore, we investigate a role of cytosolic Hsp60 as a novel pro-inflammatory mediator in VSMCs. Hsp60 was detected in the cytosol of VSMCs. The selective depletion of cytosolic Hsp60 in VSMCs reduced the IKK activation, repressed the induction of NF-κB-dependent pro-survival genes (MnSOD and Bfl-1/A1), and enhanced apoptotic death in response to TNF-α. Moreover, a quantitative RNA sequencing revealed that the expression of 75 genes among the 774 TNF-α-inducible genes was significantly reduced by the depletion of cytosolic Hsp60. In particular, the expression of pro-inflammatory cytokines/chemokines, such as CCL2, CCL20, and IL-6, was regulated by the cytosolic Hsp60 in VSMCs. Finally, the depletion of cytosolic Hsp60 markedly inhibited the neointimal thickening in the balloon-injured arterial vessels by inducing apoptotic cell death and inhibiting chemokine production. This study provides the first evidence that cytosolic Hsp60 could be a therapeutic target for preventing inflammation-driven VSMC hyperplasia in the injured vessels. Hsp60 normal vs knockout with TNF-alpha treatment
Project description:Pro-inflammatory response of VSMCs is triggered by endothelial damage and a causative step for thrombosis and neointimal thickening in the arterial vessels. Therefore, we investigate a role of cytosolic Hsp60 as a novel pro-inflammatory mediator in VSMCs. Hsp60 was detected in the cytosol of VSMCs. The selective depletion of cytosolic Hsp60 in VSMCs reduced the IKK activation, repressed the induction of NF-κB-dependent pro-survival genes (MnSOD and Bfl-1/A1), and enhanced apoptotic death in response to TNF-α. Moreover, a quantitative RNA sequencing revealed that the expression of 75 genes among the 774 TNF-α-inducible genes was significantly reduced by the depletion of cytosolic Hsp60. In particular, the expression of pro-inflammatory cytokines/chemokines, such as CCL2, CCL20, and IL-6, was regulated by the cytosolic Hsp60 in VSMCs. Finally, the depletion of cytosolic Hsp60 markedly inhibited the neointimal thickening in the balloon-injured arterial vessels by inducing apoptotic cell death and inhibiting chemokine production. This study provides the first evidence that cytosolic Hsp60 could be a therapeutic target for preventing inflammation-driven VSMC hyperplasia in the injured vessels.
Project description:To understand the effects of Hsp60 deficiency in developing vertebrates, we generated CRISPR/Cas9-mediated hspd1 knockout zebrafish lines by targeting exon 2 to induce a frameshift mutation. We selected an allele with a 56 base pair deletion inducing a frameshift mutation leading to loss of protein functions. We examined the transcriptome changes in zebrafish larvae at 5 dpf .
Project description:Glioblastoma (GBM), the most aggressive primary central nervous system (CNS) malignancy, exhibits rapid progression, therapy resistance, and inevitable recurrence—hallmarks primarily driven by glioblastoma stem cells (GSCs). Within the tumor microenvironment, dynamic crosstalk between GSCs and cytokines creates a niche for GSC maintenance. While interferon-gamma (IFN-γ) plays a well-established role in antitumor immunity, we reveal its paradoxical function in promoting the proliferation and self-renewal of GSCs. In this study, we show that IFN-γ induces the expression of HECT and RLD domain-containing E3 ubiquitin ligase 5 (HERC5) in GSCs, which functions as an ISG15 E3 ligase. HERC5 promotes mitochondrial stability by mediating the ISGylation of heat shock protein 60 (HSP60), a key mitochondrial chaperone. Genetic depletion of HERC5 leads to HSP60 degradation, mitochondrial dysfunction, and marked suppression of tumor growth, significantly prolonging survival in orthotopic GBM mouse models. These findings identify the HERC5–HSP60 axis as a critical mediator of GSC adaptation to cytokine-induced stress, highlighting HERC5 as a potential therapeutic target to disrupt GSC-driven tumorigenesis.
Project description:Deficiency of the mitochondrial chaperone HSP60 has detrimental effects on the mitochondrial functions, and can in patient’s lead to hypomyelination disorder. The present study investigates the proteome in cultivated skin fibroblasts originating from two patients with HSP60 genetic variants and hypomyelination.