Cell Stress & Chaperones最新文献

HSP90 is a ubiquitously expressed chaperone protein that regulates the maturation of numerous substrate proteins called 'clients'. The glycoprotein fibronectin (FN) is an important protein of the extracellular matrix (ECM) and a client protein of HSP90. FN and HSP90 interact directly, and the FN ECM is regulated by exogenous HSP90 or HSP90 inhibitors. Here, we extend the analysis of the HSP90 - FN interaction. The importance of the N-terminal 70-kDa fragment of fibronectin (FN70) and FN type I repeat was demonstrated by competition for FN binding between HSP90 and the functional upstream domain (FUD) of the Streptococcus pyogenes F1 adhesin protein. Furthermore, His-HSP90α mutations F352A and Y528A (alone and in combination) reduced the association with full-length FN (FN-FL) and FN70 in vitro. Unlike wild type His-HSP90α, these HSP90 mutants did not enhance FN matrix assembly in the Hs578T cell line model when added exogenously. Interestingly, the HSP90 E353A mutation, which did not significantly reduce the HSP90 - FN interaction in vitro, dramatically blocked FN matrix assembly in Hs578T cell-derived matrices. Taken together, these data extend our understanding of the role of HSP90 in FN fibrillogenesis and suggest that promotion of FN ECM assembly by HSP90 is not solely regulated by the affinity of the direct interaction between HSP90 and FN.

Nuclear factor erythroid 2-related factor 2 (Nrf2), a transcriptional regulator, is the predominant factor in modulating oxidative stress and other cellular signaling responses. Studies from our lab and others highlighted that activation of the Nrf2 pathway by small molecules improves endothelial function by suppressing oxidative and endoplasmic reticulum (ER) stress. However, the exact mechanisms by which Nrf2 elicits these effects are unknown. In the present study, we developed CRISPR/Cas9-mediated Nrf2 knocked-out human endothelial cells, and proteomic signature was studied using LC-MS/MS. We identified 723 unique proteins, of which 361 proteins were found to be differentially regulated and further screened in the Nrf2ome online database, where we identified a highly interconnected signaling network in which 70 proteins directly interact with Nrf2. These proteins were found to regulate some key cellular and metabolic processes in the regulation actin cytoskeleton, ER stress, angiogenesis, inflammation, Hippo signaling pathway, and epidermal growth factor/fibroblast growth factor (EGF/FGF) signaling pathway. Our findings suggest the role of Nrf2 in maintaining endothelium integrity and its relationship with the crucial cellular processes which help develop novel therapeutics against endothelial dysfunction and its associated complications.

In the current investigation, we explored the benefits of aucubin against rodent ischemia/reperfusion (I/R) damages in brains and elucidated the role of 5'-AMP-activated protein kinase (AMPK) in its neuroprotective action. I/R model of brain was established in male three-month-old rats through 2 h of middle cerebral artery occlusion followed by two days of reperfusion. Aucubin boosted phosphorylation of AMPKα in ipsilateral cortex of injured rats. Then, rats were exposed to cerebral I/R damage and received treatment of aucubin and compound C (a well-known AMPK inhibitor). It was found that aucubin administration improved neurological symptom score, decreased infarct volume, and mitigated cerebral edema in injured rats. Aucubin administration upregulated Nrf2 expression and abated oxidative stress in ipsilateral cortex of injured rats. Aucubin administration reduced levels of multiple pro-inflammatory cytokines, suppressed microglial activation and neutrophil infiltration, and promoted M2 polarization in injured rats. More importantly, compound C abolished the neuroprotective, anti-oxidant and inflammation-modulating effects of aucubin in injured rats, at least in part. Therefore, we concluded that activation of AMPK by aucubin alleviated I/R injury in brain through abating oxidative stress and suppressing inflammation, identifying a potential candidate for those patients of ischemic stroke.

Adriamycin (ADR) is an important chemotherapeutic drug, but it has serious side effects such as hepatotoxicity. This study aimed to evaluate whether N-acetylcysteine (NAC) has hepatoprotective effects against ADR-induced hepatotoxicity in rats. In addition, it was aimed to determine how Meteorin-Like (MtrnL), which has pleiotropic effects on immunology, inflammation, and metabolism, is affected by ADR and/or NAC applications in liver tissue. 28 rats were randomly assigned to one of four equal groups in the study: control (no treatment), NAC (150 mg/kg/day of NAC intraperitoneally (i.p), ADR (15 mg/kg only on the first day of the experiment), and ADR + NAC (ADR 15 mg/kg on the first day of the experiment + 150 mg/kg/day NAC i.p). After 15 days, liver enzyme levels in serum, oxidant/antioxidant parameters in liver tissue, histopathological changes, caspase 3 (Casp3) and heat shock protein 70 (HSP-70) immunoreactivities, and MtrnL levels were examined. Histopathological changes, liver enzyme levels, as well as HSP-70, and Casp3 immunoreactivities increased due to ADR application. Additionally, MtrnL levels in liver tissue were significantly increased as a result of ADR application. However, it was detected that the NAC application significantly regulated the ADR-induced changes. Furthermore, it was determined that NAC administration regulated the changes in ADR-induced oxidative stress parameters. We propose that NAC may exert a hepatoprotective effect by regulating ADR-induced altered oxidative stress parameters, MtrnL levels, Casp3, and HSP-70 immunoreactivities in the liver.

Being overweight is already considered a metabolic risk factor, which can be overcome by increasing cardiorespiratory fitness (CRF). Acute exercise is known to induce changes in plasma hormones and heat shock proteins release. However, there is a lack of studies investigating the impact of body composition and CRF on these variables following acute aerobic exercise. To assess the influence of body composition and cardiorespiratory fitness on plasma heat shock protein 72 kDa (HSP72), norepinephrine (NE), insulin, and glucose responses to an acute aerobic exercise bout in the fed state. Twenty-four healthy male adults were recruited and allocated into three groups: overweight sedentary (n = 8), normal weight sedentary (n = 8), and normal weight active (n = 8). The volunteers performed an acute moderate exercise session on a treadmill at 70% of VO₂ peak. Blood samples were drawn at baseline, immediately post-exercise, and at 1-h post-exercise. The exercise session did not induce changes in HSP72 nor NE but changes in glucose and insulin were affected by body mass index. Also, subjects with elevated CRF maintain reduced NE through exercise. At baseline, the overweight sedentary group showed elevated NE, insulin, and glucose; these last two impacting the HOMA-IR index. Thirty minutes of aerobic exercise at 70% VO₂ peak, in the fed state, did not change the levels of plasma NE and HSP72. Elevated body composition seems to impact metabolic profile and increase sympathetic activity. Conversely, subjects with increased cardiorespiratory fitness seem to have attenuated sympathetic activity.

Nuclear factor erythroid 2-related factor 2 (Nrf2), a transcriptional regulator, is the predominant factor in modulating oxidative stress and other cellular signaling responses. Studies from our lab and others highlighted that activation of the Nrf2 pathway by small molecules improves endothelial function by suppressing oxidative and endoplasmic reticulum (ER) stress. However, the exact mechanisms by which Nrf2 elicits these effects are unknown. In the present study, we developed CRISPR/Cas9-mediated Nrf2 knocked-out human endothelial cells, and proteomic signature was studied using LC-MS/MS. We identified 723 unique proteins, of which 361 proteins were found to be differentially regulated and further screened in the Nrf2ome online database, where we identified a highly interconnected signaling network in which 70 proteins directly interact with Nrf2. These proteins were found to regulate some key cellular and metabolic processes in the regulation actin cytoskeleton, ER stress, angiogenesis, inflammation, Hippo signaling pathway, and epidermal growth factor/fibroblast growth factor (EGF/FGF) signaling pathway. Our findings suggest the role of Nrf2 in maintaining endothelium integrity and its relationship with the crucial cellular processes which help develop novel therapeutics against endothelial dysfunction and its associated complications.

Acute respiratory distress syndrome (ARDS) is a common cause of hypoxemic respiratory failure in intensive care units that has increased dramatically as a result of the COVID-19 pandemic. In both COVID-19 and non-COVID ARDS, the pathogenesis of lung injury involves local (pulmonary) and systemic inflammation, leading to impaired gas exchange, requirement for mechanical ventilation, and a high risk of mortality. Heat shock protein 27 (HSP27) is a chaperone protein expressed in times of cell stress with roles in modulation of systemic inflammation via the NF-κB pathway. Given its important role as a modulator of inflammation, we sought to investigate the role of HSP27 and its associated auto-antibodies in ARDS caused by both SARS-CoV-2 and non-COVID etiologies. A total of 68 patients admitted to the intensive care unit with ARDS requiring mechanical ventilation were enrolled in a prospective, observational study that included 22 non-COVID-19 and 46 COVID-19 patients. Blood plasma levels of HSP27, anti-HSP27 auto-antibody (AAB), and cytokine profiles were measured on days 1 and 3 of ICU admission along with clinical outcome measures. Patients with COVID-19 ARDS displayed significantly higher levels of HSP27 in plasma, and a higher ratio of HSP27:AAB on both day 1 and day 3 of ICU admission. In patients with COVID-19, higher levels of circulating HSP27 and HSP27:AAB ratio were associated with a more severe systemic inflammatory response and adverse clinical outcomes including more severe hypoxemic respiratory failure. These findings implicate HSP27 as a marker of advanced pathogenesis of disease contributing to the dysregulated systemic inflammation and worse clinical outcomes in COVID-19 ARDS, and therefore may represent a potential therapeutic target.

Human Hsp70-escort protein 1 (hHep1) is a cochaperone that assists in the function and stability of mitochondrial HSPA9. Similar to HSPA9, hHep1 is located outside the mitochondria and can interact with liposomes. In this study, we further investigated the structural and thermodynamic behavior of interactions between hHep1 and negatively charged liposomes, as well as interactions with cellular membranes. Our results showed that hHep1 interacts peripherally with liposomes formed by phosphatidylserine and cardiolipin and remains partially structured, exhibiting similar affinities for both. In addition, after being added to the cell membrane, recombinant hHep1 was incorporated by cells in a dose-dependent manner. Interestingly, the association of HSPA9 with hHep1 improved the incorporation of these proteins into the lipid bilayer. These results demonstrated that hHep1 can interact with lipids also present in the plasma membrane, indicating roles for this cochaperone outside of mitochondria.

Necroptosis is a new type of programmed cell death discovered in recent years, playing an important role in various diseases. Since it was conceptualized in 2005, research on necroptosis has developed rapidly. However, few bibliometric analyses have provided a comprehensive overview of the field. This study aimed to employ a bibliometric analysis to assess necroptosis research's current status and hotspot, highlight landmark findings, and orientate future research. A total of 3993 publications from the WoSCC were collected for this study. Multiple tools were used for bibliometric analysis and data visualization, including an online website, VOSviewer, CiteSpace, and HistCite. Publications related to necroptosis have increased significantly annually, especially in the last 5 years. Globally, the USA and Harvard University are the most outstanding countries and institutions in this field, respectively. The academic groups managed by Peter Vandenabeele and Junying Yuan both have permanent and intensive research on necroptosis. Cell Death and Differentiation is the most vital journal in this field. The molecular mechanisms of necroptosis and its role in disease are the focus of current research, while the crosstalk between programmed cell death is an emerging direction in the field. The "reactive oxygen species", "innate immunity", and "programmed cell death" may be potential research hotspots. Our results present a comprehensive knowledge map and explore research trends. Researchers and funding agencies on necroptosis can obtain helpful references from our study.