Role of pyroptosis-related cytokines in the prediction of lung cancer.

Objectives: Lung cancer is the leading cause to induce cancer-related mortality. Effective biomarkers for prediction the occurrence of lung cancer is urgently needed. Our previous studies indicated that pyroptosis-related cytokines TNF-α, IFN-γ, MIP-1α, MIP-1ß, MIP-2 and IP-10 is important to influence the efficacy of chemotherapy drug in lung cancer tissues. But the role of pyroptosis-related cytokines in prediction the occurrence of lung cancer is still unknown. Methods: Blood samples were collected from 258 lung cancer patients at different stage and 80 healthy volunteers. Serum levels of pyroptosis-related cytokines including TNF-α, IFN-γ, MIP-1α, MIP-1ß, MIP-2 and IP-10 were measured by Cytometric Bead Array (CBA). ROC curve was performed to evaluate the cut-off value and diagnosis value for prediction and diagnosis of lung cancer. Results: Compared with control group, the levels of IP-10, MIP-1α, MIP-1ß, MIP-2 and TNF-α were significantly higher in lung cancer patients (45.5 (37.1-56.7): 57.2 (43.0-76.5), 34.4 (21.8-75.2): 115.4 (96.6-191.2), 49.3 (25.6-78.7): 160.5 (124.9-218.6), 22.6 (17.8-31.2): 77.9 (50.1-186.5), 3.80 (2.3-6.2): 10.3 (5.7-16.6)), but the level of IFN-γ was decreased in the patients (12.38 (9.1-27.8): 5.9 (3.5-9.7)). All the above cytokines were significantly associated with the diagnosis of lung cancer, and the AUC values of IFN-γ, IP-10, MIP-1α, MIP-1ß, MIP-2, and TNF-α were 0.800, 0.656, 0.905, 0.921, 0.914, and 0.824. And the AUC can rise to 0.986 after combining the above factors, and the sensitivity and specificity also up to 96.7 % and 93.7 %, respectively. Additionally, TNF-α (r = 0.400, P < 0.01), MIP-2 (r = 0.343, P < 0.01), MIP-1α (r = 0.551, P < 0.01) and MIP-1ß (r = 0.403, p < 0.01) were positively associated with occurrence of lung cancer, but IFN-γ (r = -0.483, p < 0.01) was negatively associated with occurrence of lung cancer. As far as the potential of early diagnosis of lung cancer, TNF-α (AUC = 0.577), MIP-1α (AUC = 0.804) and MIP-1ß (AUC = 0.791) can predict the early stage of lung cancer, and combination of the above three cytokines has a better predictive efficiency (AUC = 0.854). Conclusion: Our study establishes a link between the levels of IP-10, MIP-1α, MIP-1ß, MIP-2, TNF-α and IFN-γ and diagnosis of lung cancer. Besides, we observed a synergistic effect of these five pyroptosis-related cytokines in diagnosing lung cancer patient, suggesting their potential as biomarkers for lung cancer diagnosis. Moreover, the combination of TNF-α, MIP-1α and MIP-1ß are also potential predictors for the early diagnosis of lung cancer.

PKR deficiency delays vascular aging via inhibiting GSDMD-mediated endothelial cell hyperactivation.

Vascular aging is an independent risk factor for cardiovascular diseases, but the regulatory mechanism is not clearly understood. In this study, we found that endothelial PKR activity is elevated in aging aorta tissues, which is accompanied with increased endothelial cell hyperactivation, IL-1ß and HMGB1 release and vascular smooth muscle cell (VSMC) phenotype transforming. Global knockout of PKR exhibits significantly delayed vascular aging compared to wild-type mice at the same age. In vitro, using PKR siRNA or the cell hyperactivation inhibitor glycine or disulfiram can effectively inhibit H2O2 or palmitic acid-induced endothelial cell hyperactivation, IL-1ß and HMGB1 release and co-cultured VSMC phenotype transforming. These results demonstrate that endothelial PKR activation induces GSDMD-mediated endothelial cell hyperactivation to release HMGB1 and IL-1ß, which promotes the phenotype transforming of VSMC and subsequent accelerates the process of vascular aging. These discoveries will help to explore the new drug target to inhibit vascular aging.

RAB20 deficiency promotes the development of silicosis via NLRP3 inflammasome.

Silicosis is a worldwide serious occupational disease that is caused by inhalation of silica crystals. However, little is known about the pathogenesis mechanism of silicosis. We performed single-cell sequencing in bronchoalveolar lavage fluid (BALF) from mine workers with silicosis and their co-workers who did not develop silicosis, and found that the RAB20 deficiency in monocytes/macrophages was strongly linked to the development of silicosis. In the silicosis murine model, RAB20 knockout markedly enhanced the silica crystal-induced pulmonary interstitial fibrosis and respiratory dysfunction. Moreover, this process is strongly accompanied by IL-1ß release and NLRP3 activation. In vitro, RAB20 knockout macrophages aggravated the crystalline silica-induced IL-1ß release and NLRP3 inflammasome activation partly by increased ratio of crystalline silica/phagosomal areas/volumes to induce lysosomal injury. Thus, these findings provide novel molecular insights into the intricate mechanisms underlying lysosomal protein RAB20 that are necessary for environmental irritant-mediated innate immunity, and shed light on the future development of novel therapy target for the prevention of silicosis.

Impaired interferon-γ signaling promotes the development of silicosis.

Silicosis is caused by inhalation of crystalline silica dust particles and known as one of the most serious occupational diseases worldwide. However, little is known about intrinsic factors leading to disease susceptibility. Single-cell sequencing of bronchoalveolar lavage fluid cells of mine workers with silicosis and their co-workers who did not develop silicosis revealed that the impaired interferon (IFN)-γ signaling in myeloid cells was strongly associated with the occurrence of silicosis. Global or myeloid cell-specific deletion of interferon γ receptor (IFN-γR) markedly enhanced the crystalline silica-induced pulmonary injury in wild-type but not in NLRP3 deficient mice. In vitro, IFN-γ priming of macrophages suppressed the crystalline silica-induced NLRP3 inflammasome activation partly by inducing the formation of spacious phagosomes with relatively reduced ratio of crystalline silica/phagosomal areas volumes to resistant crystalline silica-induced lysosomal membrane damage. Thus, these findings provide molecular insights into the intricate mechanisms underlying innate immunity-mediated host responses to environmental irritants.

Silencing IFNγ inhibits A1 astrocytes and attenuates neurogenesis decline and cognitive impairment in endotoxemia.

Cognitive impairment, acute or long-term, is a common complication in patients with severe bacterial infection. However, the underlying mechanisms are not fully verified and effective medicine is not available in clinics. Interferon gamma (IFNγ) is a pivotal cytokine against infection and is believed to be a tune in homeostasis of cognitive function. Here, we collected blood and cerebrospinal fluid (CF) from human subjects and mice, and found that plasma and CF levels of IFNγ were significantly increased in septic patients and endotoxin-challenged mice when compared with healthy controls. IFNγ signaling was boosted in the hippocampus of mice after a challenge of lipopolysaccharide (LPS), which was accompanied with cognitive impairment and decline of neurogenesis. Deficiency of IFNγ or its receptor (IFNγR) dramatically attenuated microglia-induced A1 astrocytes and consequently restored neurogenesis and cognitive function in endotoxemia mice model. Using primary microglia, astrocytes and neurons, we found that IFNγ remarkably increased LPS-mediated release of TNFα and IL-1α in microglia and consequently induced the transformation of astrocyte to A1 subtype, which ultimately resulted in neuron damage. Thus, IFNγ promotes cognitive impairment in endotoxemia by enhancing microglia-induced A1 astrocytes. Targeting IFNγ would be a novel strategy for preventing or treating cognitive dysfunction in patients with Gram-negative infection.

Novel role of PKR in palmitate-induced Sirt1 inactivation and endothelial cell senescence.

Endothelial cell senescence is regarded as a vital characteristic of cardiovascular diseases. Elevated palmitate (PA) is an independent risk factor of cardiovascular diseases, but its role in endothelial cell senescence is currently unknown. During the course of studying the prosenescent role of PA, we discovered a key role of dsRNA-dependent protein kinase [protein kinase R (PKR)] in endothelial senescence. Exposure of human umbilical vein endothelial cells (HUVECs) to PA-induced cell senescence is characterized by increased levels of senescence-associated ß-galactose glucosidase activity, excessive production of reactive oxygen species production, impaired cellular proliferation, and G1 phase arrest. This phenomenon is associated with an increase of PKR autophosphorylation and decreased activity of sirtuin 1 (Sirt1), a pivotal antisenescent factor. PKR inactivation by PKR siRNA or its phosphorylation inhibitor 2-aminopurine significantly attenuated PA-induced HUVEC senescence by reversing Sirt1 activity and its downstream signaling. Moreover, to study the regulatory mechanism between PKR and Sirt1, we found that PKR promotes JNK activation to inhibit Sirt1 activity and that this effect could be reversed by the JNK inhibitor SP600125. These findings provide evidence that PKR mediates PA-induced HUVEC senescence by inhibiting Sirt1 signaling. Our study provides novel insights into the actions and mechanisms of PKR in endothelial senescence. NEW & NOTEWORTHY This study first provides a novel observation that dsRNA-dependent protein kinase (PKR) mediates palmitate-induced sirtuin 1 inactivation and subsequent human umbilical vein endothelial cell senescence. Most importantly, these new findings will provide a potential therapeutic strategy to improve free fatty acid-induced endothelial senescence by targeting PKR in cardiovascular diseases.

[Role of high mobility group protein B1 in IL-1α-induced endothelial cell senescence].

OBJECTIVE: To explore the effect of interleukin-1α (IL-1α) on the senescence of human umbilical vein endothelial cells (HUVECs) and the function of high mobility group protein 1 (HMGB1).
 Methods: HUVECs were randomly divided into a control group, a IL-1α group (10 ng/mL IL-1α), a HMGB1 group (100 ng/mL HMGB1), and a HMGB1+IL-1α group (100 ng/mL of HMGB1 plus 10 ng/mL of IL-1α). Senescence associated ß-galactosidase (SA ß-gal) staining was used to assess the number of senescent cells, Western blot were performed to detect the protein levels of silent information regulator 1(SIRT1), and quantitative real-time PCR (qRT-PCR) was used to detect the mRNA levels of p53, p21 and p16.
 Results: Compared with the control group, the number of SA ß-gal positive cells were significantly increased in the IL-1α group (P<0.05), while the expression of SIRT1 protein significantly decreased (P<0.01). Compared with the IL-1α group, the expression of SA ß-gal positive cells in the HMGB1+IL-1α group was decreased and the mRNA levels of p21 and p53 were down-regulated (all P<0.05), however, there was no statistical significance in the mRNA expression of p16 (P>0.05).
 Conclusion: IL-1α can induce the senescence of HUVECs, and HMGB1 may inhibit IL-1α-induced endothelial cell senescence via p53-p21 pathway.

[Progress in the study on roles of cathepsin in hypertension].

Cardiovascular remodeling or dysfunction-induced abnormal cardiac output, blood volume and peripheral vascular resistance is an important pathophysiological mechanism for the occurrence and development of hypertension. Cathepsins are widely expressed in human various tissue and cells and they are involved in the pathogenesis of hypertension through activation of renin - angiotensin system, degradation of cytoplasmic matrix, proliferation of smooth muscle cell and hypertrophy of myocyte. The clinical studies have found that cathepsins can be used as a biomarker for hypertension. In recent years, the studies on the functions and mechanisms of cathepsins have provided a new sight and strategy for treatment of hypertension.