Copy number amplification-induced overexpression of lncRNA LOC101927668 facilitates colorectal cancer progression by recruiting hnRNPD to disrupt RBM47/p53/p21 signaling.

BACKGROUND: Somatic copy number alterations (SCNAs) are pivotal in cancer progression and patient prognosis. Dysregulated long non-coding RNAs (lncRNAs), modulated by SCNAs, significantly impact tumorigenesis, including colorectal cancer (CRC). Nonetheless, the functional significance of lncRNAs induced by SCNAs in CRC remains largely unexplored. METHODS: The dysregulated lncRNA LOC101927668, induced by copy number amplification, was identified through comprehensive bioinformatic analyses utilizing multidimensional data. Subsequent in situ hybridization was employed to ascertain the subcellular localization of LOC101927668, and gain- and loss-of-function experiments were conducted to elucidate its role in CRC progression. The downstream targets and signaling pathway influenced by LOC101927668 were identified and validated through a comprehensive approach, encompassing RNA sequencing, RT-qPCR, Western blot analysis, dual-luciferase reporter assay, evaluation of mRNA and protein degradation, and rescue experiments. Analysis of AU-rich elements (AREs) within the mRNA 3' untranslated region (UTR) of the downstream target, along with exploration of putative ARE-binding proteins, was conducted. RNA pull-down, mass spectrometry, RNA immunoprecipitation, and dual-luciferase reporter assays were employed to elucidate potential interacting proteins of LOC101927668 and further delineate the regulatory mechanism between LOC101927668 and its downstream target. Moreover, subcutaneous xenograft and orthotopic liver xenograft tumor models were utilized to evaluate the in vivo impact of LOC101927668 on CRC cells and investigate its correlation with downstream targets. RESULTS: Significantly overexpressed LOC101927668, driven by chr7p22.3-p14.3 amplification, was markedly correlated with unfavorable clinical outcomes in our CRC patient cohort, as well as in TCGA and GEO datasets. Moreover, we demonstrated that enforced expression of LOC101927668 significantly enhanced cell proliferation, migration, and invasion, while its depletion impeded these processes in a p53-dependent manner. Mechanistically, nucleus-localized LOC101927668 recruited hnRNPD and translocated to the cytoplasm, accelerating the destabilization of RBM47 mRNA, a transcription factor of p53. As a nucleocytoplasmic shuttling protein, hnRNPD mediated RBM47 destabilization by binding to the ARE motif within RBM47 3'UTR, thereby suppressing the p53 signaling pathway and facilitating CRC progression. CONCLUSIONS: The overexpression of LOC101927668, driven by SCNAs, facilitates CRC proliferation and metastasis by recruiting hnRNPD, thus perturbing the RBM47/p53/p21 signaling pathway. These findings underscore the pivotal roles of LOC101927668 and highlight its therapeutic potential in anti-CRC interventions.

SIRT6 alleviates senescence induced by Porphyromonas gingivalis in human gingival fibroblasts.

OBJECTIVE: Bidirectional influences between senescence and inflammation are newly discovered. This study aimed to clarify the roles and mechanism of Porphyromonas gingivalis (P. gingivalis) in exacerbating senescence in human gingival fibroblasts (HGFs). DESIGN: Subgingival plaque and gingivae were collected from twenty-four periodontitis patients and eighteen periodontally healthy subjects. Quantities of P. gingivalis in subgingival plaque were explored using real-time PCR and the expressions of p53, p21 and SIRT6 in gingivae were detected by IHC. Moreover, senescence in HGFs was induced by P. gingivalis lipopolysaccharide (LPS) and the expressions of senescence-related ß-galactosidase (SA-ß-gal), p53, p21 and senescence-associated secretory phenotype (IL-6 and IL-8) with or without treatment by SIRT6 activator UBCS039 were explored by IHC, western blot and ELISA, respectively. In addition, the levels of SIRT6, Nrf2, HO-1 and reactive oxygen species (ROS) were examined by western blot and flow cytometry. RESULTS: Quantities of P. gingivalis in subgingival plaque and semi-quantitative scores of p53 and p21 in gingivae of periodontitis patients were increased compared with healthy controls (p < 0.05), while SIRT6 score in periodontitis patients was decreased (p < 0.001). Quantities of P. gingivalis were positively correlated with p53 and p21 scores (0.6 < r < 0.9, p < 0.01), and negatively correlated with SIRT6 score (-0.9 < r<-0.6, p < 0.01). Moreover, P. gingivalis LPS increased the levels of SA-ß-gal, p53, p21, IL-6, IL-8 and ROS and decreased the levels of SIRT6, Nrf2 and HO-1 in HGFs, which was rescued by UBCS039 (p < 0.05). CONCLUSIONS: P. gingivalis LPS could induce senescence of HGFs, which could be reversed by SIRT6 via Nrf2-HO-1 signaling pathway.

Inhibitory Effects of Royal Jelly and Its Functional Components on the Proliferation of MKN-28 Gastric Cancer Cells.

Royal jelly (RJ) is a natural food product with nutritional value and anticancer activity. However, their effects on gastric cancer are unclear. Here, we show that treatment with 5-320 µg/mL of RJ, ethanol extract (RJEE), and protein hydrolyzate (RJPH) decreased the viability of MKN-28 gastric cancer cells, with a half-maximal inhibitory concentration of 123.22 µg/mL for RJEE. RJ, RJEE, and RJPH increase the lactate dehydrogenase release rate and change the morphology of the cells, resulting in cell shrinkage, nucleoplasm condensation, and the formation of apoptotic bodies. RJ and its functional components stagnated the cell cycle in the G0/G1 phase, accompanied by the accumulation of reactive oxygen species, decreased mitochondrial membrane potential, and increased expression levels of p53 and p21 proteins, caspase-3 activation, and apoptosis. Therefore, RJ, RJEE, and RJPH have potential inhibitory effects on the proliferation of gastric cancer cells.

Targeting the p90RSK/MDM2/p53 Pathway Is Effective in Blocking Tumors with Oncogenic Up-Regulation of the MAPK Pathway Such as Melanoma and Lung Cancer.

In most human tumors, the MAPK pathway is constitutively activated. Since p90RSK is downstream of MAPK, it is often hyperactive and capable of phosphorylating oncogenic substrates. We have previously shown that p90RSK phosphorylates MDM2 at S166, promoting p53 degradation in follicular thyroid carcinomas. Thus, the inhibition of p90RSK restores p53 expression, which in turn inhibits cell proliferation and promotes apoptosis. In the present study, we demonstrated that the p90RSK/MDM2/p53 pathway proved to be an excellent target in the therapy of tumors with MAPK hyperactivation. For this purpose, we selected p53wt melanoma, lung and medullary thyroid carcinoma cell lines with high activation of p90RSK. In these cell lines, we demonstrated that the p90RSK/MDM2/p53 pathway is implicated in the regulation of the cell cycle and apoptosis through p53-dependent transcriptional control of p21 and Bcl-2. Furthermore, with an immunohistochemical evaluation of primary melanomas and lung tumors, which exhibit highly activated p90RSK compared to corresponding normal tissue, we demonstrated that MDM2 stabilization was associated with p90RSK phosphorylation. The results indicate that p90RSK is able to control the proliferative rate and induction of apoptosis through the regulation of p53wt levels by stabilizing MDM2 in selected tumors with constitutively activated MAPKs, making p90RSK a new attractive target for anticancer therapy.

miR-96-5p expression is sufficient to induce and maintain the senescent cell fate in the absence of stress.

Senescence is a cell fate driven by different types of stress that results in exit from the cell cycle and expression of an inflammatory senescence-associated secretory phenotype (SASP). Here, we demonstrate that stable overexpression of miR-96-5p was sufficient to induce cellular senescence in the absence of genotoxic stress, inducing expression of certain markers of early senescence including SASP factors while repressing markers of deep senescence including LINE-1 and type 1 interferons. Stable miR-96-5p overexpression led to genome-wide changes in heterochromatin followed by epigenetic activation of p16Ink4a, p21Cip1, and SASP expression, induction of a marker of DNA damage, and induction of a transcriptional signature similar to other senescent lung and endothelial cell types. Expression of miR-96-5p significantly increased following senescence induction in culture cells and with aging in tissues from naturally aged and Ercc1-/Δ progeroid mice. Mechanistically, miR-96-5p directly suppressed expression of SIN3B and SIN3 corepressor complex constituents KDM5A and MORF4L2, and siRNA-mediated knockdown of these transcriptional regulators recapitulated the senescent phenotype. In addition, pharmacologic inhibition of the SIN3 complex suppressed senescence and SASP markers. These results clearly demonstrate that a single microRNA is sufficient to drive early senescence in the absence of genotoxic stress through targeting epigenetic and transcriptional regulators, identifying novel targets for the development of senotherapeutics.

Ochratoxin A-induced DNA damage triggers G2 phase arrest via hMLH1-p53-p21 signaling pathway in human gastric epithelium immortalized cells in vitro.

Ochratoxin A (OTA), as one of the most important and harmful mycotoxins, is classed as possible human carcinogen (group 2B). As we all know, DNA damage may cause genomic instability, cell cycle disorder, activation of DNA damage pathway, and stimulation of DNA repair system. To explore the roles of DNA damage repair protein (hMLH1) on OTA-induced G2 arrest, the DNA damage, chromosome aberration, cell cycle distribution and p53-p21 signaling pathway were evaluatd after different time OTA exposure (6, 12, 24, 48 h) in immortalized human gastric epithelial cells (GES-1). Our results demonstrated that OTA exposure could trigger genomic instability, DNA damage and G2 phase arrest of GES-1 cells. At the same time, OTA treatment could increase the expression of hMLH1, and induce phosphorylation of the p53 protein, as well as p21, in response to DNA damage. Finally, inhibition of hMLH1 by siRNA effectively prevented the activation of p53-p21 signaling pathway and rescued the G2 arrest elicited by OTA. This study demonstrated that hMLH1-p53-p21 signaling pathway played an important role in DNA damage and G2 cell cycle arrest the mediated by OTA in GES-1 cells.

PiRNA CFAPIR inhibits cardiac fibrosis by regulating the muscleblind-like protein MBNL2.

Myocardial fibroblasts transform into myofibroblasts during the progression of cardiac fibrosis, together with excessive cardiac fibroblast proliferation. Hence, the prevention and treatment of cardiac fibrosis are significant factors for inhibiting the development of heart failure. P-element Induced WImpy testis-interacting RNAs (PiRNA) are widely expressed in the heart, but their involvement in cardiac fibrosis has not yet been confirmed. We identified differentially expressed PiRNAs using Arraystar PiRNA expression profiling in Angiotensin II models of cardiac fibrosis in vivo and in vitro. We then explored cardiac-fibrosis-associated PiRNA-related proteins, RNA-protein interactomes, immunoprecipitation, and pulldown. We detected fibrosis markers and pathway-related proteins using immunofluorescence, qRT-PCR, and Western blot. We uncovered cardiac fibrosis associated PiRNA (CFAPIR) that was obviously dysregulated during cardiac fibrosis, whereas its overexpression reversed fibrosis in vivo and in vitro. Mechanistically, CFAPIR competitively bound muscleblind like protein 2 (MBNL2) and the cyclin-dependent kinase inhibitor P21 to regulate the TGF-ß1/SMAD3 signaling pathway.

PRMT1 mediates the proliferation of Y79 retinoblastoma cells by regulating the p53/p21/CDC2/cyclin B pathway.

Retinoblastoma (RB) is the most common intraocular malignancy among children and presents a certain mortality risk, especially in low- and middle-income countries. Clarifying the molecular mechanisms underlying the onset and progression of retinoblastoma is vital for devising effective cancer treatment approaches. PRMT1, a major type I PRMT, plays significant roles in cancer development. However, its expression and role in retinoblastoma are still unclear. Our research revealed a marked increase in PRMT1 levels in both retinoblastoma tissues and Y79 cells. The overexpression of PRMT1 in Y79 cells promoted their growth and cell cycle progression. Conversely, the suppression of PRMT1 hindered the growth of Y79 cells and impeded cell cycle progression. Mechanistically, PRMT1 mediated the growth of Y79 retinoblastoma cells by targeting the p53/p21/CDC2/Cyclin B pathway. Additionally, the ability of PRMT1 knockdown to suppress cell proliferation was also observed in vivo. Overall, PRMT1 could function as a potential target for therapeutic treatment in individuals with retinoblastoma.

Deacetylation of HnRNP U mediated by sirtuin1 ameliorates aged rat with liver fibrosis via inhibiting p53-related senescence and NLRP3-related inflammation.

Senescence represents a major risk factor promoting liver fibrosis progression. Sirtuin 1 (SIRT1), an essential regulator of cellular senescence, may be involved in developing liver fibrosis. However, the role and mechanism of SIRT1 in liver fibrosis development were largely unknown. We constructed the liver fibrosis in aged rats induced by carbon tetrachloride (CCl4) and then transfected with GFP-SIRT1 adenoviral vectors. After that, we performed acetylomic analysis of liver tissue in aged rats to identify potential substrates of SIRT1. Furthermore, replicative senescent rat hepatocytes were pretreated with siRNA HnRNP U, SIRT1 adenoviral vectors, resveratrol, and siRNA SIRT1, following stimulation with H2O2. We found that the protein levels of SIRT1 and HnRNP U were down-regulation in aged rat liver fibrotic tissues, with an accumulation of NLRP3 inflammasome and activation of the p53/p21 pathway in liver tissue, as well as an increased level of plasma IL-1ß secretion. In comparison, these effects were reversed by overexpressing SIRT1 with adenoviral vectors. Acetylation of HnRNP U and its sites at K28 and K787 might be potential targets for SIRT1-mediated liver fibrosis in aged rats. Silencing HnRNP U reduced H2O2-induced up-regulation expression of p53, p21, and NLRP3 inflammasome at protein levels. Additionally, H2O2 induced high acetylation of HnRNP U in senescent hepatocytes, whereas overexpressing SIRT1 with adenoviral vectors and resveratrol deacetylate HnRNP U to inhibit NLRP3 inflammasome and the p53/p21 pathway. Besides, the silence of SIRT1 aggravated H2O2-induced p53-related senescence and NLRP3-related inflammation in senescent hepatocytes. Our findings suggested that deacetylation of HnRNPU mediated by SIRT1 attenuated liver fibrosis in the elderly by inhibiting p53/p21 pathway and NLRP3-related inflammation.

Bone Marrow Mesenchymal Stem Cells-Derived Extracellular Vesicle miR-208a-3p Alleviating Spinal Cord Injury via Regulating the Biological Function of Spinal Cord Neurons.

We aim to explore the potential mechanism of bone marrow mesenchymal stem cells-derived extracellular vesicles (BMSCs-Exo) in improving spinal cord injury (SCI). Thirty male 12-week specific pathogen-free (SPF) Sprague-Dawley (SD) rats were used to construct SCI model in vivo. Ten male 12-week SPF SD rats were used to extract BMSCs. The Basso, Beattie, Bresnahan (BBB) score was used to evaluate the motor function of rats. Real-time fluorescence quantitative PCR (RT-PCR), western blot (WB), and double luciferase assay were used to explore the regulation between rno-miR-208a-3p and Cdkn1a (p21) in BMSCs. Primary spinal cord neurons were treated with lipopolysaccharide (100 ng/mL) for 30 min to mimic SCI in vitro. Compared with the model group (14 scores), BMSCs-Exo increased BBB score (19 scores) in SCI rats. Compared with the sham group, Cdkn1a was upregulated, whereas rno-miR-208a-3p was downregulated in the model group. However, compared with the model group, Cdkn1a was downregulated, whereas rno-miR-208a-3p was upregulated in the BMSCs-Exo group. In addition, rno-miR-208a-3p inhibited the expression of Cdkn1a via direct binding way. BMSCs-Exo-rno-miR-208a-3p promoted the proliferation of primary spinal neurons via inhibiting apoptosis in vitro. Moreover, BMSCs-Exo-rno-miR-208a-3p promoted cyclin D1, CDK6, and Bcl-2 and inhibited Bax expression in a cell model of SCI. In conclusion, BMSCs-Exo-carried rno-miR-208a-3p significantly protects rats from SCI via regulating the Cdkn1a pathway.

FOXM1 affects oxidative stress, mitochondrial function, and the DNA damage response by regulating p21 in aging oocytes.

Fertilization capacity and embryo survival rate are decreased in postovulatory aging oocytes, which results in a reduced reproductive rate in female animals. However, the key regulatory genes and related regulatory mechanisms involved in the process of postovulatory aging in oocytes remain unclear. In this study, RNA-Seq revealed that 3237 genes were differentially expressed in porcine oocytes between the MII and aging stages (MII + 24 h). The expression level of FOXM1 was increased at the aging stage, and FOXM1 was also observed to be enriched in many key biological processes, such as cell senescence, response to oxidative stress, and transcription, during porcine oocyte aging. Previous studies have shown that FOXM1 is involved in the regulation of various biological processes, such as oxidative stress, DNA damage repair, mitochondrial function, and cellular senescence, which suggests that FOXM1 may play a crucial role in the process of postovulatory aging. Therefore, in this study, we investigated the effects and mechanisms of FOXM1 on oxidative stress, mitochondrial function, DNA damage, and apoptosis during oocyte aging. Our study revealed that aging oocytes exhibited significantly increased ROS levels and significantly decreased GSH, SOD, T-AOC, and CAT levels than did oocytes at the MII stage and that FOXM1 inhibition exacerbated the changes in these levels in aging oocytes. In addition, FOXM1 inhibition increased the levels of DNA damage, apoptosis, and cell senescence in aging oocytes. A p21 inhibitor alleviated the effects of FOXM1 inhibition on oxidative stress, mitochondrial function, and DNA damage and thus alleviated the degree of senescence in aging oocytes. These results indicate that FOXM1 plays a crucial role in porcine oocyte aging. This study contributes to the understanding of the function and mechanism of FOXM1 during porcine oocyte aging and provides a theoretical basis for preventing oocyte aging and optimizing conditions for the in vitro culture of oocytes.

Pituitary tumor­transforming gene 1 regulates the senescence and apoptosis of oral squamous cell carcinoma in a p21­dependent DNA damage response manner.

Pituitary tumor­transforming gene 1 (PTTG1), also known as securin, is a proto­oncogene involved in the development of various cancers by promoting cell proliferation and mobility. However, its underlying biological mechanisms in oral squamous cell carcinoma (OSCC) progression remain unclear. in the present study, it was sought to elucidate the role of PTTG1 as an oncogene in OSCC progression and was attempted to unravel the underlying mechanism and impact of PTTG1 expression on cell cycle, cell death, and cellular senescence. The effect of double strand break on PTTG1 expression was investigated in OSCC growth. To identify the role of PTTG1 in OSCC growth, the cell viability and senescence was analyzed by EdU and senescence­associated beta­galactosidase (SA­ß­gal) assay, respectively. To verify the DNA damage­induced senescence of PTTG1, the chromosomal damage in OSCC was analyzed in vitro. Finally, the effect of PTTG1 on tumor growth and gene expression related to cell viability and DNA damaged­induced senescence was investigated in vivo. PTTG1 expression was compared between OSCC and healthy patient samples (n=32) using reverse transcription­quantitative PCR and immunohistochemistry; and it was found that PTTG1 expression was upregulated in OSCC. Small interfering RNA­mediated knockdown of PTTG1 in two OSCC cell lines revealed that PTTG1 downregulation significantly inhibited cell proliferation and arrested the cell cycle pathway as evidenced by changes in checkpoint genes (such as cyclin D1, E and B1). PTTG1 knockdown also increased apoptosis, as evidenced by the upregulation of apoptotic genes [such as cleaved (c­) Caspase­7 and c­poly (ADP­ribose) polymerase]. Moreover, PTTG1 downregulation promoted cellular senescence, as shown by western blotting and SA­ß­gal staining. Finally, senescence­induced DNA damage was observed in OSCC cells, which accelerates genomic instability, through chromosomal damage analysis. Taken together, the present findings suggested that PTTG1 acts as a proto­oncogene; regulates cell proliferation, cell cycle, cellular senescence and DNA damage in OSCC; and may serve as a novel diagnostic biomarker and potential therapeutic target for OSCC.

Intermittent clearance of p21-highly-expressing cells extends lifespan and confers sustained benefits to health and physical function.

A key challenge in aging research is extending lifespan in tandem with slowing down functional decline so that life with good health (healthspan) can be extended. Here, we show that monthly clearance, starting from 20 months, of a small number of cells that highly express p21Cip1 (p21high) improves cardiac and metabolic function and extends both median and maximum lifespans in mice. Importantly, by assessing the health and physical function of these mice monthly until death, we show that clearance of p21high cells improves physical function at all remaining stages of life, suggesting healthspan extension. Mechanistically, p21high cells encompass several cell types with a relatively conserved proinflammatory signature. Clearance of p21high cells reduces inflammation and alleviates age-related transcriptomic signatures of various tissues. These findings demonstrate the feasibility of healthspan extension in mice and indicate p21high cells as a therapeutic target for healthy aging.

UBE2D1 promotes glioblastoma proliferation by modulating p21 ubiquitination.

Glioblastoma (GBM) cells exhibit aberrant proliferative abilities and resistance to conventional therapies. However, the mechanisms underlying these malignant phenotypes are poorly understood. In this study, we identified ubiquitin-conjugating enzyme E2D1 (UBE2D1) as a crucial stimulator of GBM development. It is highly expressed in GBM and closely associated with poor prognosis in patients with GBM. UBE2D1 knockdown inhibits GBM cell growth and leads to G1 cell cycle arrest. Mechanistically, UBCH5A binds to p21 at the protein level and induces the ubiquitination and degradation of p21. This negative regulation is mediated by STUB1. Our findings are the first to identify UBE2D1 as a key driver of GBM growth and provide a potential target for improving prognosis and therapy.

Astaxanthin Induces Apoptosis in MCF-7 Cells through a p53-Dependent Pathway.

Astaxanthin (3,3'-dihydroxy-ß,ß-carotene-4,4'-dione; AXT) is a xanthophyll ß-carotenoid found in microalgae, seafood, fungi, complex plants, flamingos, and quail. It is well known that AXT plays a role as a drug with antioxidant and antitumor properties. Furthermore, several studies have reported that the reagent shows anti-inflammatory and neuroprotective effects. Recently, it was found that AXT acts as a peroxisome proliferator-activated receptor γ (PPARγ) modulator. To investigate the effect of AXT on MCF-7 cells (a human breast cancer cell line), the cells were treated with various concentrations of AXT. The treatment induced the decrease in cell number in a dose-dependent manner. Additionally, the Annexin V-positive cells were increased by the AXT treatment. These results indicated that apoptosis was induced in the tumor cells through the treatment of AXT. To elucidate the connection between apoptosis and p53, the levels of p53 and p21 proteins were assessed. Consequently, it was observed that the expression of p53 and p21 increased proportionally to the concentration of the AXT treatment. These findings suggest that the apoptosis of MCF-7 cells induced by AXT operates through a p53-dependent pathway, implying that AXT could potentially have a beneficial role in future breast cancer treatments. Thus, our results will provide a direction for future cancer challenges.

[Mechanism of Huangqin Qingre Chubi Capsules regulating p53/p21 signaling pathway to delay chondrocyte senescence in osteoarthritic rats].

This study aims to investigate the mechanism of Huangqin Qingre Chubi Capsules(HQC) in delaying chondrocyte senescence of osteoarthritic(OA) rats by regulating the p53/p21 signaling pathway. Rheumatic fever paralysis models of OA rats were induced based on monosodiun iodoacetate(MIA) combined with external rheumatic fever environmental stimuli and divided into normal(Con) group, OA model(MIA) group, OA model+rheumatic fever stimulation model(MIA-M) group, MIA-M+HQC low-dose(MIA-M+HQC-L) group, medium-dose(MIA-M+HQC-M) group, and high-dose(MIA-M+HQC-H) group, and MIA-M+glucosamine(MIA-M+GS) group. The models were successfully prepared and administered by gavage for 30 d. The pathological changes of cartilage were observed by hematoxylin-eosin(HE) and Senna O solid green(SO) staining. The expression of interleukin(IL)-1ß and IL-6 was detected by enzyme-linked immunosorbent assay(ELISA). Flow cytometry(FCM) was used to detect apoptosis and cell cycle. The mRNA expression of MMP13, ADAMTS-5, COLⅡ, and TGF-ß was detected by RT-qPCR. The protein expression of p53/p21, p16, Bax, and Bcl-2 was detected by Western blot. The articular cartilage surface of rats in the Con group was smooth, and the tide line was smooth. The cartilage layer of MIA and MIA-M groups was obviously damaged, and the cartilage matrix was reduced. The above conditions were more severe in the MIA-M group. The cartilage surface of the HQC high-dose group and MIA-M+GS group was basically intact with clear delamination. Compared with the MIA-M+HQC-H group, Mankin's score was higher in the HQC low-dose and medium-dose groups, and the change was not obvious in the MIA-M+GS group. Compared with the Con group, the proportion of chondrocytes G_1 was elevated in the MIA and MIA-M groups, and the proportion of the S phase and G_2 phase was significantly decreased. In addition, the apoptosis rate was increased. Compared with MIA-M, HQC groups inhibited apoptosis and promoted cell proliferation in a concentration-dependent manner. Compared with the MIA-M+HQC-H group, the effect was more significant in the HQC high-dose group than in the HQC medium-low dose, while it was not significant in the MIA-M+GS group. Compared with the Con group, IL-1ß and IL-6 were elevated in the MIA and MIA-M groups, and mRNA levels of MMP13 and ADAMTS-5 were elevated. p53, p21, p16, and Bax protein were elevated, and mRNA levels of COLⅡ and TGF-ß were decreased. Compared with the MIA-M group, IL-1ß and IL-6 decreased after drug interventions of HQC and GS, and mRNA levels of MMP13 and ADAMTS-5, as well as protein levels of p53, p21, Bax, and p16 decreased. In addition, Bcl-2 increased. The improvement of these indexes was significantly better in the MIA-M+HQC-H group than in the HQC low-dose and medium-dose groups, and the difference with the MIA-M+GS group was not significant. HQC delayed MIA-induced chondrocyte senescence in OA rats, inhibited inflammatory response and extracellular matrix(ECM) degradation, and its mechanism may be related to the inhibition of the p53/p21 pathway.

Essential role of p21Waf1/Cip1 in the modulation of post-traumatic hippocampal Neural Stem Cells response.

BACKGROUND: Traumatic Brain Injury (TBI) represents one of the main causes of brain damage in young people and the elderly population with a very high rate of psycho-physical disability and death. TBI is characterized by extensive cell death, tissue damage and neuro-inflammation with a symptomatology that varies depending on the severity of the trauma from memory loss to a state of irreversible coma and death. Recently, preclinical studies on mouse models have demonstrated that the post-traumatic adult Neural Stem/Progenitor cells response could represent an excellent model to shed light on the neuro-reparative role of adult neurogenesis following damage. The cyclin-dependent kinase inhibitor p21Waf1/Cip1 plays a pivotal role in modulating the quiescence/activation balance of adult Neural Stem Cells (aNSCs) and in restraining the proliferation progression of progenitor cells. Based on these considerations, the aim of this work is to evaluate how the conditional ablation of p21Waf1/Cip1 in the aNSCS can alter the adult hippocampal neurogenesis in physiological and post-traumatic conditions. METHODS: We designed a novel conditional p21Waf1/Cip1 knock-out mouse model, in which the deletion of p21Waf1/Cip1 (referred as p21) is temporally controlled and occurs in Nestin-positive aNSCs, following administration of Tamoxifen. This mouse model (referred as p21 cKO mice) was subjected to Controlled Cortical Impact to analyze how the deletion of p21 could influence the post-traumatic neurogenic response within the hippocampal niche. RESULTS: The data demonstrates that the conditional deletion of p21 in the aNSCs induces a strong increase in activation of aNSCs as well as proliferation and differentiation of neural progenitors in the adult dentate gyrus of the hippocampus, resulting in an enhancement of neurogenesis and the hippocampal-dependent working memory. However, following traumatic brain injury, the increased neurogenic response of aNSCs in p21 cKO mice leads to a fast depletion of the aNSCs pool, followed by declined neurogenesis and impaired hippocampal functionality. CONCLUSIONS: These data demonstrate for the first time a fundamental role of p21 in modulating the post-traumatic hippocampal neurogenic response, by the regulation of the proliferative and differentiative steps of aNSCs/progenitor populations after brain damage.

Caveolin-2 controls preadipocyte survival in the mitotic clonal expansion for adipogenesis.

Here, we report that Caveolin-2 (Cav-2) is a cell cycle regulator in the mitotic clonal expansion (MCE) for adipogenesis. For the G2/M phase transition and re-entry into the G1 phase, dephosphorylated Cav-2 by protein tyrosine phosphatase 1B (PTP1B) controlled epigenetic activation of Ccnb1, Cdk1, and p21 in a lamin A/C-dependent manner, thereby ensuring the survival of preadipocytes. Cav-2, associated with lamin A/C, recruited the repressed promoters of Ccnb1 and Cdk1 for activation, and disengaged the active promoter of p21 from lamin A/C for inactivation through histone H3 modifications at the nuclear periphery. Cav-2 deficiency abrogated the histone H3 modifications and impeded the transactivation of Ccnb1, Cdk1, and p21, leading to a delay in mitotic entry, retardation of re-entry into G1 phase, and the apoptotic cell death of preadipocytes. Re-expression of Cav-2 restored the G2/M phase transition and G1 phase re-entry, preadipocyte survival, and adipogenesis in Cav-2-deficient preadipocytes. Our study uncovers a novel mechanism by which cell cycle transition and apoptotic cell death are controlled for adipocyte hyperplasia.

Overcoming Vemurafenib Resistance in Metastatic Melanoma: Targeting Integrins to Improve Treatment Efficacy.

Metastatic melanoma, a deadly form of skin cancer, often develops resistance to the BRAF inhibitor drug vemurafenib, highlighting the need for understanding the underlying mechanisms of resistance and exploring potential therapeutic strategies targeting integrins and TGF-ß signalling. In this study, the role of integrins and TGF-ß signalling in vemurafenib resistance in melanoma was investigated, and the potential of combining vemurafenib with cilengitide as a therapeutic strategy was investigated. In this study, it was found that the transcription of PAI1 and p21 was induced by acquired vemurafenib resistance, and ITGA5 levels were increased as a result of this resistance. The transcription of ITGA5 was mediated by the TGF-ß pathway in the development of vemurafenib resistance. A synergistic effect on the proliferation of vemurafenib-resistant melanoma cells was observed with the combination therapy of vemurafenib and cilengitide. Additionally, this combination therapy significantly decreased invasion and colony formation in these resistant cells. In conclusion, it is suggested that targeting integrins and TGF-ß signalling, specifically ITGA5, ITGB3, PAI1, and p21, may offer promising approaches to overcoming vemurafenib resistance, thereby improving outcomes for metastatic melanoma patients.

Multiparametric identification of putative senescent cells in skeletal muscle via mass cytometry.

Senescence is an irreversible arrest of the cell cycle that can be characterized by markers of senescence such as p16, p21, and KI-67. The characterization of different senescence-associated phenotypes requires selection of the most relevant senescence markers to define reliable cytometric methodologies. Mass cytometry (a.k.a. Cytometry by time of flight, CyTOF) can monitor up to 40 different cell markers at the single-cell level and has the potential to integrate multiple senescence and other phenotypic markers to identify senescent cells within a complex tissue such as skeletal muscle, with greater accuracy and scalability than traditional bulk measurements and flow cytometry-based measurements. This article introduces an analysis framework for detecting putative senescent cells based on clustering, outlier detection, and Boolean logic for outliers. Results show that the pipeline can identify putative senescent cells in skeletal muscle with well-established markers such as p21 and potential markers such as GAPDH. It was also found that heterogeneity of putative senescent cells in skeletal muscle can partly be explained by their cell type. Additionally, autophagy-related proteins ATG4A, LRRK2, and GLB1 were identified as important proteins in predicting the putative senescent population, providing insights into the association between autophagy and senescence. It was observed that sex did not affect the proportion of putative senescent cells among total cells. However, age did have an effect, with a higher proportion observed in fibro/adipogenic progenitors (FAPs), satellite cells, M1 and M2 macrophages from old mice. Moreover, putative senescent cells from muscle of old and young mice show different expression levels of senescence-related proteins, with putative senescent cells of old mice having higher levels of p21 and GAPDH, whereas putative senescent cells of young mice had higher levels of IL-6. Overall, the analysis framework prioritizes multiple senescence-associated proteins to characterize putative senescent cells sourced from tissue made of different cell types.