Down-regulation of XBP1s alleviates the senescence of renal tubular epithelial cells induced by hypoxia/reoxygenation through Sirt3/SOD2/mtROS signaling pathway / 器官移植

Objective To investigate the role and mechanism of spliced X-box binding protein 1 (XBP1s) in the senescence of primary renal tubular epithelial cells induced by hypoxia/reoxygenation (H/R). Methods Primary renal tubular epithelial cells were divided into the normal control group (NC group), H/R group, empty adenovirus negative control group (Ad-shNC group), targeted silencing XBP1s adenovirus group (Ad-shXBP1s group), empty adenovirus+H/R treatment group (Ad-shNC+H/R group) and targeted silencing XBP1s adenovirus+H/R treatment group (Ad-shXBP1s +H/R group), respectively. The expression levels of XBP1s in the NC, H/R, Ad-shNC and Ad-shXBP1s groups were measured. The number of cells stained with β-galactosidase, the expression levels of cell aging markers including p53, p21 and γH2AX, and the levels of reactive oxygen species (ROS), malondialdehyde (MDA) and superoxide dismutase (SOD) were determined in the Ad-shNC, Ad-shNC+H/R and Ad-shXBP1s+H/R groups. Chromatin immunoprecipitation was employed to verify Sirtuin 3 (Sirt3) of XBP1s transcription regulation, and the expression levels of Sirt3 and downstream SOD2 after down-regulation of XBP1s were detected. Mitochondrial reactive oxygen species (mtROS) were detected by flow cytometry. Results Compared with the NC group, the expression level of XBP1s was up-regulated in the H/R group. Compared with the Ad-shNC group, the expression level of XBP1s was down-regulated in the Ad-shXBP1s group (both P<0.001). Compared with the Ad-shNC group, the number of cells stained with β-galactosidase was increased, the expression levels of p53, p21 and γH2AX were up-regulated, the levels of ROS, MDA and mtROS were increased, the SOD activity was decreased, the expression level of Sirt3 was down-regulated, and the ratio of Ac-SOD2/SOD2 was increased in the Ad-shNC+H/R group. Compared with the Ad-shNC+H/R group, the number of cells stained with β-galactosidase was decreased, the expression levels of p53, p21 and γH2AX were down-regulated, the levels of ROS, MDA and mtROS were decreased, the SOD activity was increased, the expression level of Sirt3 was up-regulated and the ratio of Ac-SOD2/SOD2 was decreased in the Ad-shXBP1s+H/R group (all P<0.05). Conclusions Down-regulation of XBP1s may ameliorate the senescence of primary renal tubular epithelial cells induced by H/R, which probably plays a role through the Sirt3/SOD2/mtROS signaling pathway.

Genética y genómica de la longevidad y el envejecimiento / Genetics and genomics of longevity and aging

El envejecimiento y la longevidad son procesos que involucran una serie de factores genéticos, bioquímicos y ambientales. En esta revisión se tratan algunas cuestiones sobre estos dos procesos biológicos y epigenéticos. Se presentan los genes más importantes en estos procesos, así como se ejemplifican enfermedades que presentan un aceleramiento o falla en la longevidad y el envejecimiento. Se usa el análisis inteligente de datos para hallar interacciones de proteínas/genes que expliquen estos dos fenómenos biológicos.

Aging and longevity are processes that involve a series of genetic, biochemical and environmental factors. This review addresses some issues about these two biological and epigenetic processes. The most important genes in these processes are presented, as well as diseases that present an acceleration or failure in longevity and aging. Intelligent data analysis is used to find protein/gene interactions that explain these two biological phenomena.

Senescence in oral lichen planus as assessed by the immunohistochemical evaluation of senescence marker protein-30 (Regucalcin)

Background: Oral lichen planus is a T-cell-mediated chronic inflammatory disease affecting approximately 1% to 2% of the population, the etiology of which is currently unknown. The objectives of this study were to observe if senescence occurs in oral lichen planus, through the assessment of the immunohistochemical expression of a novel marker for senescence called Senescence marker protein-30 or regucalcin, and compare the expression to that in oral lichenoid reaction and non-specific inflammation. Subjects and Methods: The study material consisted of 30 cases of oral lichen planus, 15 cases of oral lichenoid reaction and 15 cases of non-specific inflammation. The number of positive cells in ten randomly selected high power fields were counted in the epithelium and the connective tissue separately and the mean was determined. Results: Mann–Whitney U test was used to statistically analyze if there was any significant difference in the expression of Senescence marker protein-30 between oral lichen planus, oral lichenoid reaction and non-specific inflammation. Even though a greater expression was seen in the oral lichen planus cases than oral lichenoid reaction, the difference in both the epithelium and connective tissue was not statistically significant. Conclusion: This study shows that in addition to the already known mechanisms like apoptosis and increased cell proliferation rates, the activated T-lymphocytes may also trigger a senescent change in the cells of oral lichen planus. As with the other mechanisms, this is also seen only in a small proportion of the cases.

Downregulated miR-181a alleviates H2O2-induced oxidative stress and cellular senescence by targeting PDIA6 in human foreskin fibroblasts

Abstract Background Oxidative stress is strongly associated with cellular senescence. Numerous studies have indicated that microRNAs (miRNAs) play a critical part in cellular senescence. MiR-181a was reported to induce cellular senescence, however, the potential mechanism of miR-181a in hydrogen peroxide (H2O2)-induced cellular senescence remains obscure. Objective The aim of this study is to investigate the role and regulatory mechanism of miR-181a in H2O2-induced cellular senescence. Methods Human foreskin fibroblasts (HFF) transfected with miR-181a inhibitor/miR-NC with or without H2O2 treatment were divided into four groups: control + miR-NC/miR-181a inhibitor, H2O2 + miR-NC/miR-181a inhibitor. CCK-8 assay was utilized to evaluate the viability of HFF. RT-qPCR was used to measure the expression of miR-181a and its target genes. Protein levels of protein disulfide isomerase family A member 6 (PDIA6) and senescence markers were assessed by western blotting. Senescence-associated β-galactosidase (SA-β-gal) staining was applied for detecting SA-β-gal activity. The activities of SOD, GPx, and CAT were detected by corresponding assay kits. The binding relation between PDIA6 and miR-181a was identified by luciferase reporter assay. Results MiR-181a inhibition suppressed H2O2-induced oxidative stress and cellular senescence in HFF. PDIA6 was targeted by miR-181a and lowly expressed in H2O2-treated HFF. Knocking down PDIA6 reversed miR-181a inhibition-mediated suppressive impact on H2O2-induced oxidative stress and cellular senescence in HFF. Study limitations Signaling pathways that might be mediated by miR-181a/PDIA6 axis were not investigated. Conclusion Downregulated miR-181a attenuates H2O2-induced oxidative stress and cellular senescence in HFF by targeting PDIA6.

Research progress of cellular senescence in glaucoma / 中华实验眼科杂志

Cellular senescence is a response process in which cells are activated by ischemia, hypoxia, oxidative stress, DNA damage, reactive oxygen species deposition and other stimulations.Senescent cells markers include such as senescence-associated β-galactosidase (SA-β-gal) activation, P16INK4a upregualtion, senescence-associated heterochromatic foci (SAHF) accumulation, senescence-associated secretory phenotype (SASP) generation, telomere shortening and so on.P16INK4a/Rb and P19 ARF/P53/P21 Cip1 pathways are two classic cell senescence signaling pathways, which are interconnected and independent on each other.In recent years, glaucoma is considered as a blinding eye disease associated with cell senescence.Research on cell senescence in glaucoma mainly focuses on trabecular meshwork and Schlemm cannel endothelial cells senescence leading to increased resistance of aqueous humor outflow pathway, and the mechanism of retinal ganglion cells senescence and treatment in glaucoma.As an irreversible stage before cell death, deeper study on the mechanism of retinal ganglion cells senescence, and specific blocking of cell senescence will provide a new target for reducing the aqueous humor outflow resistance and protecting the optic nerve in glaucoma.This article reviewed characteristics, inducements, molecular signaling pathways of cellular senescence in glaucoma.

Research progress on the mechanism of bone marrow suppression after chemotherapy / 国际肿瘤学杂志

As an effective treatment for cancer, chemotherapy not only removes tumor cells, but also produces obvious killing effects on proliferating cells, especially hematopoietic cells, resulting in bone marrow suppression after chemotherapy, and affecting the effects of chemotherapy drug treatment and treatment cycle. Therefore, starting from the aspects of hematopoietic microenvironment damage and hematopoietic stem cell aging, to explore the mechanism of myelosuppression after chemotherapy, which provides new ideas and theoretical support for the intervention and management of bone marrow suppression after cancer chemotherapy.

The role of hyperoxia-induced cellular senescence in bronchopulmonary dysplasia / 国际儿科学杂志

Bronchopulmonary dysplasia(BPD)is a chronic respiratory system disease that causes respiratory failure and death in premature infants, and hyperoxic exposure is the main risk factor for its occurrence.Cellular senescence describes a state of cell cycle blockade, and in recent years studies have confirmed that exposure to hyperoxia can cause cellular senescence.Cellular senescence plays a crucial role in the development of the lung epithelium, lung interstitium, pulmonary vasculature, and airways, and abnormal development of these tissues is associated with the development of BPD.Therefore, this paper takes cellular senescence and BPD as the starting point to review the mechanism of hyperoxia-induced cellular senescence in the occurrence and development of BPD and the anti-aging drugs currently applied in clinical practice, in order to provide a new direction for the prevention and treatment of BPD.

Intervention effect of physical exercise on silicotic mice / 环境与职业医学

Background Pneumoconiosis is the most serious occupational disease in China, and silicosis accounts for about half of it. Any intervention effect of physical exercise as the key and core of lung rehabilitation training on silicosis is still unclear. Objective To explore potential intervention effect of physical exercise on silicotic mice. Methods Forty SPF C57BL/6 male mice were randomly divided into four groups, 10 in each group, including a control group, a physical exercise group, a silicosis model group, and a silicosis model + physical exercise intervention group. Silicotic mouse model was established by using 50 μL SiO2 suspension (200 mg·mL−1). A treadmill was used to prepare mice receiving physical exercise at 0° inclination, 12.3 m·min−1, 60 min·d−1, 5 d·week−1 for 4 weeks. Pathological morphology of lung tissues was evaluated after hematoxylin-eosin (HE) staining; deposition of collagen in lung tissues was evaluated after Van Gieson (VG) staining; expression of p-protein kinase R-like endoplasmic reticulum kinase (PERK) was detected by immunofluorescence staining; expressions of cyclin dependent kinase inhibitors (p21) and p-p38 mitogen activated protein kinase (p38) were detected by immunohistochemistry. The protein expressions of endoplasmic reticulum stress signal factors [p-inositol-requiring enzyme-1α (p-IRE-1α), p-PERK, and p-eukaryotic initiation factor-2α (p-eIF-2α)], senescence signal factors (p-p53, p21, and p16), mitogen-activated protein kinase (MAPK) signal factors [p-p38, p-extracellular regulated protein kinases (p-ERK), and p-stress-activated protein kinase (p-JNK)] were detected by Western blotting. Results After designed acute SiO2 exposure, the images of micro computed tomography (CT) showed high density shadows in lung tissues of the silicotic mice and less shadows in lung tissues of the physical exercise intervention mice. After HE staining, the proportions of silicotic nodule area in lung tissues was (18.67±3.89) % in the silicosis model group, and significantly decreased to (8.78±1.05) % in the silicosis model + physical exercise intervention group (P<0.05). After VG staining, the proportion of collagen fiber area of lung tissues was (10.37±2.18) % in the silicosis model group, and significantly decreased to (4.35±0.89) % in the silicosis model + physical exercise intervention group (P<0.05). The results of immunofluorescence staining showed that in the silicosis model group, the expression of p-PERK increased at the location of silicotic nodules, while in the silicotic model + physical exercise intervention group, the expression of p-PERK decreased. The immunohistochemical staining results showed that the expression of p21 and p-p38 increased in the lung tissues of the silicosis model group; the expression of p21 and p-p38 decreased in the lung tissues of the silicosis model + physical exercise intervention group. The results of Western blotting showed that compared with the control group, the expression levels of p-IRE-1α (0.11±0.03), p-PERK (0.95±0.40), p-eIF-2α (3.53±0.91), p-p53 (1.78±0.07), p21 (1.98±0.10), p16 (1.26±0.17), p-p38 (0.41±0.09), p-ERK (0.42±0.05), and p-JNK (3.20±1.23) of the silicosis model group were all upregulated (P<0.05). Compared with the silicosis model group, the expression levels of p-IRE-1α (0.03±0.01), p-PERK (0.31±0.12), p-eIF-2α (0.30±0.06), p-p53 (0.76±0.08), p21 (0.18±0.11), p16 (0.70±0.24), p-p38 (0.03±0.00), p-ERK (0.19±0.03), and p-JNK (0.46±0.21) of the silicosis model + physical exercise intervention group were downregulated (P<0.05). Conclusion Physical exercise may alleviate pulmonary fibrosis in silicotic mice, and inhibit abnormal expressions of endoplasmic reticulum stress signal, MAPK signal, and senescent signal.

Research Progress of the Effect of Microgravity on Cellular Senescence / 医用生物力学

Microgravity is a typical feature of the space. A large number of space flights and foundation simulation experiments have shown that cells show typical biological characteristics of aging, such as reduced cell proliferation and cell cycle arrest under microgravity or simulated microgravity. However, the molecular mechanism by which microgravity or simulated microgravity affects cellular senescence is not well understood. Understanding the mechanism controlling cellular senescence induced by microgravity environment is helpful for exploring anti-aging strategies and targeted interventions in space. In recent years, domestic and foreign scholars have carried out a number of researches and explorations on the effect of microgravity and simulated microgravity on cellular senescence as well as the related mechanisms. In this review, the latest research progress of this filed was summarized.

Construction and Validation of A Risk Model for Predicting Prognosis and Immunotherapy Response of Bladder Cancer Based on Cellular Senescence-related Genes / 肿瘤防治研究

Objective To evaluate the prognosis and immunotherapy response of patients with bladder cancer by constructing a risk-score model of cellular senescence-related signature (SRS), as well as to explore the clinical application value of SRS in bladder cancer. Methods Senescence genes were screened from TCGA-BLCA, and cellular SRS genes were screened according to LASSO regression. A bladder cancer risk-score model was constructed based on the SRS genes to analyze the survival difference and model-fit degree of TCGA-BLCA high- and low-risk groups. Univariable and multivariable Cox regression was used to analyze the prognostic risk factors of bladder cancer. Overall survival differences of high- and low-risk groups in GEO-BLCA database were verified, and variations in immunotherapy responses were analyzed in IMvigor210 databases. According to the result of β-gal chromogenic reaction in bladder cancer and normal paracancer tissues, the existence of cell senescence was determined. Results Eight marker genes were screened, and patients were divided into high- and low-risk groups according to the median risk score constructed by the marker genes. The 5-year survival rate of high risk group was lower than that of low risk group (training and validation sets P < 0.05). The area under the ROC curve of TCGA-BLCA in 1-, 3-, and 5-year were 0.657, 0.660, and 0.688, and those for GSE13507 were 0.665, 0.665, and 0.613, respectively. SRS risk score can be used as an independent risk factor for the prognosis of patients with bladder cancer. The SRS risk score in the response group was lower than that in the non-response group during bladder cancer immunotherapy (P < 0.05). The β-gal staining of bladder cancer tissue was positive, but the β-gal staining of adjacent normal tissue was negative. Conclusion Cell senescence occurs in bladder cancer tissues. SRS risk score can predict the clinical prognosis of patients with bladder cancer, and patients with low score can benefit from immunotherapy. SRS is a reliable biomarker for the prognosis and immunotherapy response of bladder cancer.

Lamin B1 regulates the growth of hepatocellular carcinoma cells by influencing telomerase activity / 生物工程学报

Lamin B1 (LMNB1) is highly expressed in liver cancer tissues, and its influence and mechanism on the proliferation of hepatocellular carcinoma cells were explored by knocking down the expression of the protein. In liver cancer cells, siRNAs were used to knock down LMNB1. Knockdown effects were detected by Western blotting. Changes in telomerase activity were detected by telomeric repeat amplification protocol assay (TRAP) experiments. Telomere length changes were detected by quantitative real-time polymerase chain reaction (qPCR). CCK8, cloning formation, transwell and wound healing were performed to detect changes in its growth, invasion and migration capabilities. The lentiviral system was used to construct HepG2 cells that steadily knocked down LMNB1. Then the changes of telomere length and telomerase activity were detected, and the cell aging status was detected by SA-β-gal senescence staining. The effects of tumorigenesis were detected by nude mouse subcutaneous tumorigenesis experiments, subsequent histification staining of tumors, SA-β-gal senescence staining, fluorescence in situ hybridization (FISH) for telomere analysis and other experiments. Finally, the method of biogenesis analysis was used to find the expression of LMNB1 in clinical liver cancer tissues, and its relationship with clinical stages and patient survival. Knockdown of LMNB1 in HepG2 and Hep3B cells significantly reduced telomerase activity, cell proliferation, migration and invasion abilities. Experiments in cells and tumor formation in nude mice had demonstrated that stable knockdown of LMNB1 reduced telomerase activity, shortened telomere length, senesced cells, reduced cell tumorigenicity and KI-67 expression. Bioinformatics analysis showed that LMNB1 was highly expressed in liver cancer tissues and correlated with tumor stage and patient survival. In conclusion, LMNB1 is overexpressed in liver cancer cells, and it is expected to become an indicator for evaluating the clinical prognosis of liver cancer patients and a target for precise treatment.

Chronic Injury of Mice Bone Marrow Multipotent Hematopoietic Progenitor Cells Induced by Ionizing Radiation / 中国实验血液学杂志

OBJECTIVE@#To explore the chronic injury and its possible mechanism of ionizing radiation on multipotent hematopoietic progenitor cells (MPPs) by determining the related indicators of MPPs in bone marrow of mice post-radiation.@*METHODS@#Sixteen C57BL/6 adult mice were randomly divided into normal control and irradiation groups, 8 mice in each group. The mice in irradiation group were exposed to 6 Gy X-ray. The proportion of bone marrow MPPs, their apoptosis and proliferation 2 months after irradiation were detected by flow cytometry. Mitochondrial activity and levels of reactive oxygen species (ROS) in each MPPs population were detected by Mitotracker Red and DCFDA probes, and the senescent state of MPPs in the bone marrow was analyzed.@*RESULTS@#Ionizing radiation could reduce the proportion of MPPs in mouse bone marrow. The proportions and numbers of MPP1, MPP3 and MPP4 in the bone marrow were significantly decreased after whole-body irradiation with 6 Gy X-ray (P<0.05). In addition, radiation significantly reduced the colony-forming capacity of MPPs in bone marrow (P<0.05), the proportions of apoptotic cells in the MPP1 and MPP4 cell populations increased significantly in the bone marrow (P<0.05). The activity of mitochondria was significantly reduced in the bone marrow MPP2, MPP3 and MPP4 cell populations compared with that of the control group (P<0.05). It was also found that the radiation could significantly increase the ROS levels of MPPs in bone marrow, and the content of ROS in the MPP2, MPP3 and MPP4 cell population of the bone marrow was significantly increased(P<0.05). The senescent cells ratios of MPP1, MPP3 and MPP4 cells in the bone marrow after irradiation were significantly higher than those in the control group (P<0.05).@*CONCLUSION@#Ionizing radiation can cause chronic MPPs damage in mice, which is closely associated with persistent oxidative stress, cells apoptosis, and cellular senescence.

Periplaneta americana extract CⅡ-3 induces senescence of leukemia K562 cells via SIRT1/mTOR signaling pathway / 中国中药杂志

This study aims to investigate the role of slient mating-type information regulation 2 homolog 1(SIRT1)/tuberous sclerosis complex 2(TSC2)/mammalian target of rapamycin(mTOR) signaling pathways in the Periplaneta americana extract CⅡ-3-induced senescence of human leukemia K562 cells. K562 cells were cultured in vitro and treated with 0(control), 5, 10, 20, 40, 80, and 160 μg·mL~(-1) of P. americana extract CⅡ-3. Cell counting kit-8(CCK-8) and flow cytometry were employed to examine the proliferation and cell cycle of the K562 cells. Senescence-associated β-galactosidase stain kit(SA-β-gal) was used to detect the positive rate of senescent cells. Mitochondrial membrane potential was detected by flow cytometry. The relative mRNA level of telomerase reverse transcriptase(TERT) was determined by fluorescence quantitative PCR. The mRNA and protein levels of SIRT1, TSC2, and mTOR were determined by fluorescence quantitative PCR and Western blot, respectively. The results showed that CⅡ-3 significantly inhibited the proliferation of K562 cells and the treatment with 80 μg·mL~(-1) CⅡ-3 for 72 h had the highest inhibition rate. Therefore, 80 μg·mL~(-1) CⅡ-3 treatment for 72 h was selected as the standard for subsequent experiments. Compared with the control group, CⅡ-3 increased the proportion of cells arrested in G_0/G_1 phase, decreased the proportion of cells in S phase, increased the positive rate of SA-β-Gal staining, elevated the mitochondrial membrane potential and down-regulated the mRNA expression of TERT. Furthermore, the mRNA expression of SIRT1 and TSC2 was down-regulated, while the mRNA expression of mTOR was up-regulated. The protein expression of SIRT1 and p-TSC2 was down-regulated, while the protein expression of p-mTOR was up-regulated. The results indicated that P. americana extract CⅡ-3 induced the senescence of K562 cells via the SIRT1/mTOR signaling pathway.

Multiple characteristic alterations and available therapeutic strategies of cellular senescence / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Given its state of stable proliferative inhibition, cellular senescence is primarily depicted as a critical mechanism by which organisms delay the progression of carcinogenesis. Cells undergoing senescence are often associated with the alteration of a series of specific features and functions, such as metabolic shifts, stemness induction, and microenvironment remodeling. However, recent research has revealed more complexity associated with senescence, including adverse effects on both physiological and pathological processes. How organisms evade these harmful consequences and survive has become an urgent research issue. Several therapeutic strategies targeting senescence, including senolytics, senomorphics, immunotherapy, and function restoration, have achieved initial success in certain scenarios. In this review, we describe in detail the characteristic changes associated with cellular senescence and summarize currently available countermeasures.

Identification of senescence-related molecular subtypes and key genes for prostate cancer / 亚洲男科学杂志(英文版)

We identified distinct senescence-related molecular subtypes and critical genes among prostate cancer (PCa) patients undergoing radical prostatectomy (RP) or radical radiotherapy (RT). We conducted all analyses using R software and its suitable packages. Twelve genes, namely, secreted frizzled-related protein 4 (SFRP4), DNA topoisomerase II alpha (TOP2A), pleiotrophin (PTN), family with sequence similarity 107 member A (FAM107A), C-X-C motif chemokine ligand 14 (CXCL14), prostate androgen-regulated mucin-like protein 1 (PARM1), leucine zipper protein 2 (LUZP2), cluster of differentiation 38 (CD38), cartilage oligomeric matrix protein (COMP), vestigial-like family member 3 (VGLL3), apolipoprotein E (APOE), and aldehyde dehydrogenase 2 family member (ALDH2), were eventually used to subtype PCa patients from The Cancer Genome Atlas (TCGA) database and GSE116918, and the molecular subtypes showed good correlations with clinical features. In terms of the tumor immune environment (TME) analysis, compared with cluster 1, cancer-associated fibroblasts (CAFs) scored significantly higher, while endothelial cells scored lower in cluster 2 in TCGA database. There was a statistically significant correlation between both CAFs and endothelial cells with biochemical recurrence (BCR)-free survival for PCa patients undergoing RP. For the GSE116918 database, cluster 2 had significantly lower levels of CAFs and tumor purity and higher levels of stromal, immune, and Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data (ESTIMATE) scores than cluster 1; in addition, patients with high levels of CAFs, stromal scores, immune scores, and ESTIMATE scores and low levels of tumor purity tended to suffer from BCR. Based on the median of differentially expressed checkpoints, high expression of CD96, hepatitis A virus cellular receptor 2 (HAVCR2), and neuropilin 1 (NRP1) in GSE116918 and high expression of CD160 and tumor necrosis factor (ligand) superfamily member 18 (TNFSF18) in TCGA database were associated with a significantly higher risk of BCR than their counterparts. In conclusion, we first constructed distinct molecular subtypes and critical genes for PCa patients undergoing RP or RT from the fresh perspective of senescence.

Role of lysosomal damage in senescence of SH-SY5Y cells induced by methylmercury and intervention of melatonin / 环境与职业医学

Background Methylmercury (MeHg) is a neurotoxin, and melatonin (MT) has a protective effect on the nervous system, but whether it can antagonize MeHg-induced nerve cell damage and the associated mechanism remain unknown. Objective Human neuroblastoma cells (SH-SY5Y cells) were used as research objects. A MeHg-induced SH-SY5Y cell senescence model was established to observe autophagy related protein, lysosomal number, and function changes, as well as potential intervention role and associated mechanism of MT. Methods (1) After SH-SY5Y cells were treated with different doses of MeHg (0, 0.125, 0.25, 0.5, 1, 2, and 4 μmol·L−1) for 48 h, the cell viability was detected using a cell viability detection kit (CCK-8 method) and the viability rate was calculated. Senescent cells were detected by an acidic senescence-associated-β-galactosidase (SA-β-gal) staining. (2) A MeHg dose of 0.5 μmol·L−1 that significantly induced senescence of SH-SY5Y cells was screened, and a half and a quarter of the dose (0.25 and 0.125 μmol·L−1) were used for the middle and low dose groups, respectively. (3) In the MT intervention experiments, SH-SY5Y cells were divided into four groups, including control group (0.1% DMSO), MeHg group (0.5 μmol·L−1 MeHg), MT group (1 mmol·L−1 MT), and MT intervention group (1 mmol·L−1 MT+0.5 μmol·L−1 MeHg). In the MT intervention group, cells were exposed to 0.5 μmol·L−1 MeHg for 48 h after 24 h of 1 mmol·L−1 MT pretreatment. (4) SA-β-gal staining was conducted to observe cell senescence; Western blotting for the expression levels of senescence-associated protein p16, autophagy-associated protein p62, LC3Ⅱ, and lysosomal-associated proteins LAMP1, LAMP2, and TFEB; Lyso-Tracker Red for the quantity of lysosomes; LysoSensor Green DND-189 for lysosomal pH changes; electron microscope for the morphological changes of lysosomes. Results The results of CCK-8 indicated that the viability rate of cells decreased with the increase of MeHg exposure concentration. Compared with the control group, the SA-β-gal positive cell ratio in the 0.5 μmol·L−1 MeHg group increased by 48% (P<0.01), p16, p62, as well as LC3Ⅱ protein expressions were significantly increased (P<0.05), LAMP1 and LAMP2 protein levels, as well as the fluorescence intensities of lysosomal red and green fluorescent probes decreased with the increase of MeHg concentration (P<0.05), and the volume of lysosomes increased under the electron microscope. Compared with the MeHg group, the expression of p16 protein was decreased in the 1 mmol·L−1 MT + 0.5 μmol·L−1 MeHg group and the SA-β-gal positive cell ratio was significantly decreased by 19% (P<0.05), the protein levels of p62 and LC3Ⅱ were significantly decreased, the LAMP1 and LAMP2 protein levels and the fluorescence intensities of lysosomal red and green fluorescent probes were increased respectively, the nuclear entry of TFEB was significantly increased, and the differences were statistically significant (P<0.05). Conclusion MeHg may cause cellular senescence by reducing the number of lysosomes and impairing lysosomal activity in SH-SY5Y cells, and MT may ameliorate MeHg-induced lysosomal abnormalities in SH-SY5Y cells, thereby intervening cell senescence.

O efeito do tratamento com rapamicina em órgãos linfoides de camundongos propensos à senescência acelerada / The effect of rapamycin treatment on lymphoid organs of senescence accelerated mice prone

Envelhecer compreende um fenômeno complexo, natural e irreversível, que submete o organismo a inúmeras alterações nos processos biológicos, fisiológicos, ambientais, psicológicos, comportamentais e sociais. Esse processo é caracterizado por um declínio gradual dos mecanismos homeostáticos do organismo, intimamente relacionados com o estado senescente. A senescência, quando diz respeito ao sistema imunológico, é denominada de imunossenescência, que pode ser definida como uma parada estável do ciclo celular associada a mudanças, com uma resposta que limita a proliferação de células envelhecidas ou danificadas. A autofagia está diretamente relacionada com a manutenção do fenótipo senescente, em que a atividade autofágica exerce um papel essencial e ativo na influência da biossíntese de proteínas e organelas. Essa via é regulada naturalmente pela proteína mTOR e quimicamente pelo fármaco rapamicina. Assim, pretendemos investigar: (1) as alterações no perfil corporal e hematimêtrico dos animais ao longo do tratamento com rapamicina; (2) avaliar o perfil de citocinas; (3) observar as modificações histológicas em órgãos linfoides primários e secundário; (4) analisar as populações de células linfoides e mieloides; e (5) avaliar a capacidade proliferativa de linfócitos in vitro. Camundongos SAMP-8 e SAMR-1 foram tratados com rapamicina durante dois meses. A mensuração da massa corporal e análises hematológicas foram realizadas antes e durante o tratamento. Amostras de soro, medula óssea, timo e baço foram analisados em ensaios de ELISA, histologia, população e subpopulações de células. Alterações na massa corporal, parâmetros hematológicos e celularidade de células foram nítidas entre os dois modelos utilizados. Diferenças também foram percebidas na detecção de citocinas IL-1ß. IL-6 e TNF-α, com resultados significantes nas amostras de baço, timo e medula óssea. As citocinas IL-7 e IL-15 apresentaram diferenças de secreção entre os grupos, sendo a primeira maior detectada em camundongos com senescência acelerada tratados com rapamicina. Em nossa análise histológica observamos que os camundongos SAM-P8 apresentaram involução tímica. E nas subpopulações de linfócitos T do baço, células TCD4+ e TCD8+ estavam, respectivamente, em maior e menor quantidade nos camundongos SAM-P8 tratados com rapamicina. Dessa forma, o camundongo da linhagem SAM-P8 é um excelente modelo para se estudar as alterações da senescência, em que o mesmo apresenta características fisiológicas distintas dos camundongos utilizados como controle (SAM-R1). Além disso, verificamos que a dose de rapamicina empregada não desencadeou alterações que pudessem comprometer a resposta imunológica desses camundongos, bem como na possibilidade de atuar na resposta contra os efeitos complexos do envelhecimento

Aging comprises a complex, natural, and irreversible phenomenon, which subjects the organism to countless alterations in biological, physiological, environmental, psychological, behavioral, and social processes. This process is characterized by a gradual decline in the organism's homeostatic mechanisms, closely related to senescence effects. Senescence, when it concerns the immune system, is called immunosenescence, which can be defined as a stable cell cycle arrest associated with changes and is a response that limits the proliferation of aged or damaged cells. Autophagy is a genetically regulated, conserved cellular process and a metabolic pathway essential for maintaining cellular homeostasis, which plays a constitutive and active role in controlling the biosynthesis of proteins and organelles. This pathway is regulated naturally by mTOR or chemically by the drug rapamycin, having a direct relationship with cellular homeostasis and maintenance of the senescent phenotype. Thus, we intend to investigate: (1) the changes in the body and hematimetic profile of the animals throughout the rapamycin treatment; (2) evaluate the cytokine profile; (3) observe histological changes in primary and secondary lymphoid organs; (4) analyze lymphoid and myeloid cell populations; and (5) evaluate the proliferative capacity of lymphocytes in vitro. SAMP-8 and SAMR-1 mice were treated with rapamycin for two months. Body mass measurement and hematological analyses were performed before and during treatment. Serum, bone marrow, thymus and spleen samples were analyzed in ELISA assays, histology, cell population and subpopulations. Changes in body mass, hematological parameters, and cellularity were clear between the two models used. Differences were also noticed in the detection of cytokines IL-1ß. IL-6 and TNF-α, with significant results in the spleen, thymus and bone marrow samples. The cytokines IL-7 and IL-15 showed differences in secretion between groups, the former being higher detected in mice with accelerated senescence treated with rapamycin. In our histological analysis we observed that SAM-P8 mice showed thymic involution. And in the spleen T-lymphocyte subpopulations, TCD4+ and TCD8+ cells were, respectively, in higher and lower quantities in SAM-P8 mice treated with rapamycin. Thus, the SAM-P8 mouse is an excellent model to study the changes of senescence, since it presents physiological characteristics different from the control mice (SAM-R1). Furthermore, we verified that the dose of rapamycin used did not trigger changes that could compromise the immune response of these mice, as well as the possibility of acting in the modulatory response against the complex effects of aging

Expression of TIGIT, PD-1 and HLA-DR/CD38 markers on CD8-T cells of children and adolescents infected with HIV and uninfected controls

ABSTRACT Immune exhaustion and senescence are scarcely studied in HIV-pediatric patients. We studied the circulatory CD8 T cells activation/exhaustion and senescent phenotype of children and adolescents vertically infected with HIV or uninfected controls based on the expression of human leukocyte antigen (HLA-DR), CD38, T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT), programmed death 1 (PD-1) and CD57 by flow cytometry, during approximately one year. Eleven HIV-infected (HI) and nine HIV-uninfected (HU) children/adolescents who received two doses or one dose of meningococcal C conjugate vaccine (MenC), respectively, were involved in this study. Blood samples were collected before the immunization (T0), 1-2 months after the first dose (T1), and 1-2 months after the second dose (T2), which was administered approximately one year after the first one. HI patients not receiving combined antiretroviral therapy (cART) showed a higher frequency of CD8 T cells TIGIT+, PD-1+ or CD57+, as well as a higher frequency of CD8 T cells co-expressing CD38/HLA-DR/TIGIT or CD38/HLA-DR/PD-1 when compared to HI treated or HU individuals, at all times that they were assessed. CD8 T cells co-expressing CD38/DR/TIGIT were inversely correlated with the CD4/CD8 ratio but positively associated with viral load. The co-expression of CD38/DR/TIGIT or CD38/DR/PD-1 on CD8 T cells was also inversely associated with the CD4 T cells expressing co-stimulatory molecules CD127/CD28. The results showed a higher expression of exhaustion/senescence markers on CD8 T cells of untreated HI children/adolescents and its correlations with viral load.

Are sociodemographic and anthropometric variables effective in screening probable and confirmed sarcopenia in community-dwelling older adults? A cross-sectional study

ABSTRACT BACKGROUND: Screening for probable and confirmed sarcopenia using sociodemographic and anthropometric indicators can be a practical, cheap, and effective strategy to identify and treat older people susceptible to this condition. OBJECTIVES: To identify cutoff points for sociodemographic and anthropometric variables in screening probable and confirmed sarcopenia in community-dwelling older adults. DESIGN AND SETTING: This was a cross-sectional study of community-dwelling older adults in Araranguá, Santa Catarina, Brazil. METHODS: Sociodemographic (age, education) and anthropometric (weight, height, body mass index [BMI], waist circumference [WC], and dominant calf circumference [DCC]) factors were considered as predictors. The outcomes were probable sarcopenia (reduction in muscle strength assessed by time ≥ 15 s in the five-time sit-to-stand test) and confirmed sarcopenia (reduction in strength and muscle mass). Receiver operating characteristic curve analysis was used to analyze the ability to track sociodemographic and anthropometric variables for sarcopenia. RESULTS: In 308 older adults, WC > 91 cm in women and age > 69 years in men were useful in screening for probable sarcopenia. The variables age, weight, BMI, WC, and DCC can be used to screen for sarcopenia in older women and men. CONCLUSION: Sociodemographic and anthropometric variables are simple and accessible tools for sarcopenia screening in older adults.

Anti-senescence effect of acetyl dipeptide-1 cetyl ester on skin and its mechanism / 中国药科大学学报

@#Acetyl dipeptide-1 cetyl ester (AD-1) is a synthetic peptide composed of acetic acid and cetyl alcohol with arginine and tyrosine, which has certain anti-inflammatory and skin barrier enhancement effects, has been used in cosmetics for sensitive skin.Meanwhile, the ingredient has also been used in anti-aging cosmetics, but there is a lack of published scientific evidence on anti- senescence aspect.In this study, we investigated the related effects of AD-1 by evaluating its in vitro antioxidant and antiglycation efficacies.Furthermore, we established a photoaging model on primary rat dermal fibroblasts by repeated exposures to UVA irradiation.MTT assay was used to detect the effects of AD-1 on the cell viability.RT-qPCR was used to determine the effects of AD-1 on the mRNA levels of senescence-related p21, p53, MMPs, IL6, Col1, Col3 and autophagy-related p62, ATG5, ATG7.Western blot was used to detect the effects of AD-1 on the protein levels of p16, p21, p53, Col1, LC3B and p62.SA-β-gal was performed to indicate senescence level of the cell.MDC was performed to indicate autophagy level.Intracellular reactive oxygen species were monitored by fluorescent probes DCFH-DA.The results showed that AD-1 could reduce UVA-induced the cell damage and regulate the abnormal expression of mRNA levels. It alleviated the abnormal protein levels of p16, p21, p53, Col1, LC3B and p62 induced by UVA. These results suggested that AD-1 has not only antioxidant and antiglycation effects but also can activate autophagy to achieve anti-senescence effect.