BACKGROUND AND AIMS:Inflammageing represents both a critical pathophysiological hallmark and independent risk factor for myocardial infarction (MI), with age-related increases observed in MI incidence and severity of post-MI ventricular remodelling. Novel therapeutic strategies targeting inflammageing-driven mechanisms are urgently required to attenuate adverse ventricular remodelling following MI. This investigation was designed to elucidate the impact of fibroblast-specific p16INK4a on inflammageing-associated ventricular remodelling after MI and to develop a targeted nanotherapy to mitigate this process. METHODS AND RESULTS:We found that p16-mediated inflammageing positively correlated with the severity of post-infarction ventricular remodelling in patients. POSTN-driven p16INK4a knockout improved cardiac function, and reduced ventricular remodelling, myocardial inflammation and NLRP3 signalling activation following MI through downregulating STAT3-mediated NLRP3 inflammasome and upregulating glutathione metabolism pathway in fibroblasts. P16INK4a overexpression induced NLRP3 signalling activation through upregulating NLRP3 transcribed by STAT3 in fibroblasts. In terms of mechanisms, p16INK4a interacted with STAT3, which depended on the SH2 domain of STAT3; P16INK4a promoted the interaction of EZH2 and STAT3, increased the di-methylation on K49 and phosphorylation on Y705 of STAT3 by EZH2, and promoted NLRP3 transcription through regulating histone modification in the NLRP3 promoter by interfering the formation of Bmi-1-EZH2 or Bmi-1-BCL6 complex in fibroblasts. Injection of p16INK4a-accumulated ageing cardiac fibroblasts, or p16INK4a overexpression adenovirus aggravated profibrosis and proinflammation in MI area. However, a novel FH peptide 'FHKHKSPALSPV'-neutrophil membrane proteins (NMPs)-artificial lipid (Li) membranes-mesoporous silica nanoparticle (MSN) core (FNLM)-nanocaged p16INK4a-siRNA, as a newly constructed nanomaterial drug, could prevent post-infarction ventricular remodelling through inhibiting NLRP3 transcription in targeted cardiac fibroblasts and ameliorating proinflammation and profibrosis. CONCLUSIONS:P16INK4a drives inflammageing-mediated post-MI ventricular remodeling by activating STAT3/NLRP3 signaling in fibroblasts. Targeting p16INK4a via FNLM-siRNA nanotherapy represents a novel strategy to ameliorate adverse cardiac remodelling, offering translational potential for clinical intervention. KEY POINTS:Mechanistic Insight: P16INK4a activates NLRP3 transcription via STAT3-EZH2 crosstalk, disrupting epigenetic complexes (Bmi-1-EZH2/BCL6) to exacerbate post-MI remodelling. Therapeutic Innovation: A fibroblast-targeted FNLM nanoparticle delivering p16INK4a-siRNA effectively silences NLRP3, reducing post-MI inflammageing. Translational Impact: This study identifies p16INK4a-STAT3 as a druggable axis and proposes FNLM-p16INK4a-siRNA as a promising nanotherapy for clinical post-MI care.
New immunosenescence targets for preventing senescence-associated pathological cardiac hypertrophy (SA-PCH) need to be explored. In the present study, with physiologically aged human and mouse samples, the IL-17A level increased with physiological aging, heart failure (HF), and SA-PCH and was negatively correlated with thymic Bmi-1 expression. Bmi-1 f/f LckCre + mice and Bmi-1 f/f littermates were generated to determine whether Bmi-1 delayed T cell aging by maintaining thymic T cell development to prevent SA-PCH. As a result, Bmi-1 promoted thymic T cell development by upregulating Notch signaling and prevented DN1 T cells from differentiating into γδT17 cells by downregulating γδT17 cell differentiation signaling. Bmi-1 upregulated Notch signaling by inhibiting p53-mediated Ikzf1 transcription at the −1,863 to −1,849 Ikzf1 promoter region. Bmi-1–RING1B promoted RORγt ubiquitination and degradation by proteasome to inhibit the production of IL-17A in γδT17 cells. Bmi-1 also downregulated Rorc transcribed by c-Maf by trimethylating H3K27 at the −1,511 to −1,497 Rorc promoter region. Subsequently, the number of peripheral γδT17 cells infiltrating the heart tissues was reduced, while alleviating IL-17A-dependent cardiac aging, hypertrophy, dysfunction, senescence-associated secretory phenotype (SASP), and macrophage–myofibroblast transition, ultimately improving SA-PCH. The RORγt inhibitor SR1001 and IL-17A neutralizing antibody ixekizumab prevented thymic RORγt-IL-17A-dependent SA-PCH. Furthermore, RORγt bound to Bmi-1 through ARG237 and to RING1B through GLU235, which could be used as a therapeutic strategy for SA-PCH to construct binding peptides promoting Bmi-1–RING1B binding to RORγt and degrading RORγt for inhibiting γδT17 cell differentiation and IL-17A production. Thus, thymic Bmi-1 prevented IL-17A-dependent SA-PCH by decreasing γδT17 cell numbers.
Vitamin D deficiency is increasingly linked to senescence-associated pulmonary fibrosis (SAPF), yet the underlying mechanisms remain incompletely understood. Here, we demonstrate that mesenchymal cell-specific overexpression of Bmi-1 significantly ameliorates SAPF induced by 1,25(OH)₂D deficiency in a mouse model. In Cyp27b1 heterozygous mice, which exhibit 1,25(OH)₂D deficiency, we observed reduced expression of both Bmi-1 and VDR with concurrent elevation of TGF-β1 in lung tissue. Transgenic Bmi-1 overexpression in mesenchymal cells markedly improved respiratory parameters, including inspiratory time, respiratory frequency, tidal volume, and minute ventilation, while reducing pathological collagen deposition and fibrotic markers. Histological and molecular analyses revealed that Bmi-1 overexpression prevented excessive extracellular matrix accumulation and preserved alveolar architecture. Mechanistically, Bmi-1 overexpression suppressed the TGF-β1/IL-11/MEK/ERK (TIME) signaling pathway, reduced cellular senescence markers (p53, p21, p16) and senescence-associated secretory phenotype factors, and inhibited myofibroblast differentiation. Furthermore, 1,25(OH)₂D deficiency-induced DNA damage and inflammatory cell infiltration were significantly attenuated by Bmi-1 overexpression. Through CUT&RUN and luciferase reporter assays, we established that 1,25(OH)₂D₃ directly regulates Tgf-β1 transcription via VDR binding to specific promoter regions, providing a molecular link between vitamin D signaling and fibrotic pathways. In primary pulmonary fibroblasts, 1,25(OH)₂D₃ treatment inhibited Tgf-β1 expression in a time-dependent manner. These findings reveal a novel protective role of Bmi-1 against vitamin D deficiency-induced SAPF and suggest that targeting the Bmi-1/VDR/TGF-β1 axis may represent a promising therapeutic strategy for fibrotic lung diseases.
Gut microbiota plays a crucial role in the host health in the aging process. However, the mechanisms for how gut microbiota triggers cellular senescence and the consequent impact on human aging remain enigmatic. Here we show that phenylacetylglutamine (PAGln), a metabolite linked to gut microbiota, drives host cellular senescence. Our findings indicate that the gut microbiota alters with age, which leads to increased production of phenylacetic acid (PAA) and its downstream metabolite PAGln in older individuals. The PAGln-induced senescent phenotype was verified in both cellular models and mouse models. Further experiments revealed that PAGln induces mitochondrial dysfunction and DNA damage via adrenoreceptor (ADR)-AMP-activated protein kinase (AMPK) signaling. Blockade of ADRs as well as senolytics therapy impede PAGln-induced cellular senescence in vivo, implying potential anti-aging therapies. This combined evidence reveals that PAGln, a naturally occurring metabolite of human gut microbiota, mechanistically accelerates host cellular senescence.
Alveolar bone defect reconstruction is a common challenge in stomatology. To address this, a thermosensitive/photosensitive gelatin methacrylate (GelMA) gel was developed based on various air solubilities and light-curing technologies. The gel was synthesized by using a freeze-ultraviolet (FUV) method to form a porous and quickly (within 15 min) solidifying modified network structure. Unlike other gel scaffolds limited by complex preparation procedures and residual products, this FUV-GelMA gel shows favorable manufacturing ability, promising biocompatibility, and adjustable macroporous structures. The results from a rat model suggested that this gel scaffold creates a conducive microenvironment for mandible reconstruction and vascularization. In vitro experiments further confirmed that the FUV-GelMA gel promotes osteogenic differentiation of human bone marrow mesenchymal stem cells and angiogenesis of human umbilical vein endothelial cells. Investigation of the underlying mechanism focused on the p38 mitogen-activated protein kinase (MAPK) pathway. We found that SB203580, a specific inhibitor of p38 MAPK, abolished the therapeutic effects of the FUV-GelMA gel on osteogenesis and angiogenesis, both in vitro and in vivo. These findings introduced a novel approach for scaffold-based tissue regeneration in future clinical applications.
In the domain of anatomy, some Chinese characters in anatomical terms possess distinctive morphological significance. Chinese characters evolved from pictographic characters, with some of these pictographs being created by ancient people based on their own body structure. This implies that the comprehension and depiction of the human body structure have been integral since the inception of Chinese characters, and this knowledge has been passed down and developed through the continued inheritance of Chinese characters. Even today, certain characters retain the appearance to reflect the shape of the human body structure. By examining the characters related to vertebrae, cranial fontanel and heart, we can find the unique and enduring link between Chinese characters and the fields of anatomy as well as Chinese traditional medicine.
Periodontitis, a prevalent inflammatory condition in the oral cavity, is closely associated with oxidative stress-induced tissue damage mediated by excessive reactive oxygen species (ROS) production. The jaw vascular unit (JVU), encompassing both vascular and lymphatic vessels, plays a crucial role in maintaining tissue fluid homeostasis and contributes to the pathological process in inflammatory diseases of the jaw. This study presents a novel approach for treating periodontitis through the development of an injectable thermosensitive gel (CH-BPNs-NBP). The gel formulation incorporates black phosphorus nanosheets (BPNs), which are notable for their ROS-scavenging properties, and dl-3-n-butylphthalide (NBP), a vasodilator that promotes lymphatic vessel function within the JVU. These results demonstrate that the designed thermosensitive gel serve as a controlled release system, delivering BPNs and NBP to the site of inflammation. CH-BPNs-NBP not only protects macrophages and human lymphatic endothelial cells from ROS attack but also promotes M2 polarization and lymphatic function. In in vivo studies, this work observes a significant reduction in inflammation and tissue damage, accompanied by a notable promotion of alveolar bone regeneration. This research introduces a promising therapeutic strategy for periodontitis, leveraging the unique properties of BPNs and NBP within an injectable thermosensitive gel.
Alveolar bone regeneration has been strongly linked to macrophage polarization. M1 macrophages aggravate alveolar bone loss, whereas M2 macrophages reverse this process. Berberine (BBR), a natural alkaloid isolated and refined from Chinese medicinal plants, has shown therapeutic effects in treating metabolic disorders. In this study, we first discovered that culture supernatant (CS) collected from BBR-treated human bone marrow mesenchymal stem cells (HBMSCs) ameliorated periodontal alveolar bone loss. CS from the BBR-treated HBMSCs contained bioactive materials that suppressed the M1 polarization and induced the M2 polarization of macrophages in vivo and in vitro. To clarify the underlying mechanism, the bioactive materials were applied to different animal models. We discovered macrophage colony-stimulating factor (M-CSF), which regulates macrophage polarization and promotes bone formation, a key macromolecule in the CS. Injection of pure M-CSF attenuated experimental periodontal alveolar bone loss in rats. Colony-stimulating factor 1 receptor (CSF1R) inhibitor or anti-human M-CSF (M-CSF neutralizing antibody, Nab) abolished the therapeutic effects of the CS of BBR-treated HBMSCs. Moreover, AKT phosphorylation in macrophages was activated by the CS, and the AKT activator reversed the negative effect of the CSF1R inhibitor or Nab. These results suggest that the CS of BBR-treated HBMSCs modulates macrophage polarization via the M-CSF/AKT axis. Further studies also showed that CS of BBR-treated HBMSCs accelerated bone formation and M2 polarization in rat teeth extraction sockets. Overall, our findings established an essential role of BBR-treated HBMSCs CS and this might be the first report to show that the products of BBR-treated HBMSCs have active effects on alveolar bone regeneration.
The excess production of reactive oxygen species (ROS) will delay tooth extraction socket (TES) healing. In this study, we developed an injectable thermosensitive hydrogel (NBP@BP@CS) used to treat TES healing. The hydrogel formulation incorporated black phosphorus (BP) nanoflakes, recognized for their accelerated alveolar bone regeneration and ROS-scavenging properties, and dl-3-n-butylphthalide (NBP), a vasodilator aimed at enhancing angiogenesis. In vivo investigations strongly demonstrated that NBP@BP@CS improved TES healing due to antioxidation and promotion of alveolar bone regeneration by BP nanoflakes. The sustained release of NBP from the hydrogel promoted neovascularization and vascular remodeling. Our results demonstrated that the designed thermosensitive hydrogel provided great opportunity not only for ROS elimination but also for the promotion of osteogenesis and angiogenesis, reflecting the "three birds with one stone" concept, and has tremendous potential for rapid TES healing.
AbstractWith the increase in the aging population, senile osteoporosis (SOP) has become a major global public health concern. Here, it is found that Prx1 and Bmi‐1 co‐localized in trabecular bone, bone marrow cavity, endosteum, and periosteum. Prx1‐driven Bmi‐1 knockout in bone‐marrow mesenchymal stem cells (BMSCs) reduced bone mass and increased bone marrow adiposity by inhibiting osteoblastic bone formation, promoting osteoclastic bone resorption, downregulating the proliferation and osteogenic differentiation of BMSCs, and upregulating the adipogenic differentiation of BMSCs. However, Prx1‐driven Bmi‐1 overexpression showed a contrasting phenotype to Prx1‐driven Bmi‐1 knockout in BMSCs. Regarding mechanism, Bmi‐1‐RING1B bound to DNMT3A and promoted its ubiquitination and inhibited DNA methylation of Runx2 at the region from 45047012 to 45047313 bp, thus promoting the osteogenic differentiation of BMSCs. Moreover, Bmi‐1‐EZH2 repressed the transcription of Cebpa by promoting H3K27 trimethylation at the promoter region −1605 to −1596 bp, thus inhibiting the adipogenic differentiation of BMSCs. It is also found that Prx1‐driven Bmi‐1 overexpression rescued the SOP induced by Prx1‐driven Bmi‐1 knockout in BMSCs. Thus, Bmi‐1 functioned as a hub protein in the epigenetic regulation of BMSCs differentiation to delay bone aging. The Prx1‐driven Bmi‐1 overexpression in BMSCs can be used as an approach for the translational therapy of SOP.
Physiologically aged lungs are prone to senescence-associated pulmonary diseases (SAPD). This study aimed to determine the mechanism and subtype of aged T cells affecting alveolar type II epithelial (AT2) cells, which promote the pathogenesis of senescence-associated pulmonary fibrosis (SAPF). Cell proportions, the relationship between SAPD and T cells, and the aging- and senescence-associated secretory phenotype (SASP) of T cells between young and aged mice were analyzed using lung single-cell transcriptomics. SAPD was monitored by markers of AT2 cells and found to be induced by T cells. Furthermore, IFNγ signaling pathways were activated and cell senescence, SASP, and T cell activation were shown in aged lungs. Physiological aging led to pulmonary dysfunction and TGF-β1/IL-11/MEK/ERK (TIME) signaling-mediated SAPF, which was induced by senescence and SASP of aged T cells. Especially, IFNγ was produced by the accumulated CD4+ effector memory T (TEM) cells in the aged lung. This study also found that physiological aging increased pulmonary CD4+ TEM cells, IFNγ was produced mainly by CD4+ TEM cells, and pulmonary cells had increased responsiveness to IFNγ signaling. Specific regulon activity was increased in T cell subclusters. IFNγ transcriptionally regulated by IRF1 in CD4+ TEM cells promoted the epithelial-to-mesenchymal transition by activating TIME signaling and cell senescence of AT2 cells with aging. Accumulated IRF1+CD4+ TEM produced IFNγ in lung with aging and anti-IRF1 primary antibody treatment inhibited the expression of IFNγ. Aging might drive T cell differentiation toward helper T cells with developmental trajectories and enhance cell interactions of pulmonary T cells with other surrounding cells. Thus, IFNγ transcribed by IRF1 in CD4+ effector memory T cells promotes SAPF. IFNγ produced by CD4+ TEM cells in physiologically aged lungs could be a therapeutic target for preventing SAPF.
BackgroundChronic changes caused by a high‐fat diet (HFD) may be associated with weakened lung function in obese patients. However, few studies have focused on the role of senescent cells in HFD‐induced pulmonary fibrosis. This study aimed to determine whether (i) obesity causes the accumulation of aging cells in the lungs, (ii) p16 accumulation in aging epithelial cells or fibroblasts exacerbates long‐term HFD‐induced senescence‐associated pulmonary fibrosis (SAPF) and (iii) p16 deletion or clearance of aging cells ameliorates HFD‐induced SAPF through inactivation of the inflammasome and metabolic remodelling.MethodsTwelve‐month old male mice of p16INK4a (hereafter p16) knockout (p16−/−) and wild‐type (WT), ApoE knockout (ApoE−/−) and ApoE−/−p16−/− were fed a HFD to induce obesity, and the effects of treatment with the senolytic drug ABT263 or the SGK1 specific inhibitor EMD638683 on fibrosis, inflammaging, gene expression, integrin‐inflammasome signalling and metabolism were examined. A549 and IMR‐90 cells were transduced with p16‐overexpressing adenovirus, and treated with palmitic and oleic acids (P&O) to induce steatosis in vitro.ResultsWe found that long‐term HFD promoted the expression of p16 and the increase of senescent cells in the lung. P16 knockout or ABT263 treatment alleviated pulmonary fibrosis, the increase of senescent cells and senescence‐associated secretory phenotype (SASP) in HFD‐fed mice, as well as in P&O‐treated A549 and IMR‐90 cells. RNA sequencing and bioinformatics analyses revealed that p16 knockout inhibited activation of the integrin‐inflammasome pathway and cellular glycolysis. Mass spectrometry, co‐immunoprecipitation and GST pull‐down assays demonstrated that p16 bound to the N‐terminal of SGK1, thereby interfering with the interaction between the E3 ubiquitin ligase NEDD4L and SGK1, and subsequently inhibiting K48‐polyubiquitin‐dependent degradation of SGK1 mediated by the NEDD4L–Ubch5 complex. EMD638683 was found to alleviate HFD‐induced pulmonary fibrosis and activation of the integrin‐inflammasome pathway.ConclusionP16 accumulation promoted activation of integrin– inflammasome pathway and cell glycolysis by binding to the N– terminal of SGK1, intefering with the interaction between the E3 ubiquitin ligase NEDD4L and SGK1, thereby inhibiting K48– polyubiquitin– dependent degradation of SGK1 mediated by the NEDD4L–Ubch5 complex. ABT263 or EMD638683 could be used as potential drugs to treat pulmonary fibrosis in obese patients.
Human amniotic mesenchymal stem cells (hAMSCs) have attracted considerable attention as a promising regenerative therapy. Many studies reported that the conditioned medium of hAMSCs (AM-CM) exerted anti-inflammatory and immunomodulatory functions, while its underlying mechanism is poorly understood. In this study, we first confirmed that AM-CM (25%, 50%, 100%) was optimal for anti-inflammation at 24 h. Lipopolysaccharide (LPS)-induced alteration of cell morphology, the decrease of cell proliferation, and the upregulation of cell apoptosis were significantly reversed in AM-CM-treated THP-1 cells. 25% and 50% AM-CM significantly decreased LPS-induced intracellular reactive oxygen species (ROS) production and proinflammatory cytokines secretion. Mechanistically, we found that AM-CM treatment suppressed LPS-induced activation of MAPK and NF-κB pathways by inhibiting CD14/TLR4 in THP-1 cells. Meanwhile, activation of NLRP3 inflammasome was also dose-dependently attenuated by AM-CM treatment. Thus, AM-CM may exert positive influences on the inflammation microenvironment and provide a novel strategy for improving tissue regeneration.
Sarcopenia increases with age, and an underlying mechanism needs to be determined to help with designing more effective treatments. This study aimed to determine whether 1,25(OH)(2)D-3 deficiency could cause cellular senescence and a senescence-associated secretory phenotype (SASP) in skeletal muscle cells to induce sarcopenia, whether GATA4 could be upregulated by 1,25(OH)(2)D-3 deficiency to promote SASP, and whether Bmi-1 reduces the expression of GATA4 and GATA4-dependent SASP induced by 1,25(OH)(2)D-3 deficiency in skeletal muscle cells. Bioinformatics analyses with RNA sequencing data in skeletal muscle from physiologically aged and young mice were conducted. Skeletal muscles from 2-month-old young and 2-year-old physiologically aged wild-type (WT) mice and 8-week-old WT, Bmi-1 mesenchymal transgene (Bmi-1(Tg)), Cyp27b1 homozygous (Cyp27b1(-/-)), and Bmi-1(Tg)Cyp27b1(-/-) mice were observed for grip strength, cell senescence, DNA damage, and NF-kappa B-mediated SASP signaling of skeletal muscle. We found that muscle-derived Bmi-1 and vitamin D receptor (VDR) decreased with physiological aging, and DNA damage and GATA4-dependent SASP activation led to sarcopenia. Furthermore, 1,25(OH)(2)D-3 deficiency promoted DNA damage-induced GATA4 accumulation in muscles. GATA4 upregulated Rela at the region from -1448 to -1412 bp at the transcriptional level to cause NF-kappa B-dependent SASP for aggravating cell senescence and muscular dysfunction and sarcopenia. Bmi-1 overexpression promoted the ubiquitination and degradation of GATA4 by binding RING1B, which prevented cell senescence, SASP, and dysfunctional muscle, and improved sarcopenia induced by 1,25(OH)(2)D-3 deficiency. Thus, Bmi-1 overexpression improves sarcopenia induced by 1,25(OH)(2)D-3 deficiency, downregulates GATA4-dependent Rela transcription, and sequentially inhibits GATA4-dependent SASP in muscle cells. Therefore, Bmi-1 overexpression could be used for translational gene therapy for the ubiquitination of GATA4 and prevention of sarcopenia. (c) 2023 American Society for Bone and Mineral Research (ASBMR).
Determining the mechanism of senescence‐associated pulmonary fibrosis is crucial for designing more effective treatments for chronic lung diseases. This study aimed to determine the following: whether Sirt1 and serum vitamin D decreased with physiological aging, promoting senescence‐associated pulmonary fibrosis by activating TGF‐β1/IL‐11/MEK/ERK signaling, whether Sirt1 overexpression prevented TGF‐β1/IL‐11/MEK/ERK signaling‐mediated senescence‐associated pulmonary fibrosis in vitamin D‐deficient ( Cyp27b1 −/− ) mice, and whether Sirt1 downregulated IL‐11 expression transcribed by TGF‐β1/Smad2 signaling through deacetylating histone at the IL‐11 promoter in pulmonary fibroblasts. Bioinformatics analysis with RNA sequencing data from pulmonary fibroblasts of physiologically aged mice was conducted for correlation analysis. Lungs from young and physiologically aged wild‐type (WT) mice were examined for cell senescence, fibrosis markers, and TGF‐β1/IL‐11/MEK/ERK signaling proteins, and 1,25(OH) 2 D 3 and IL‐11 levels were detected in serum. Nine‐week‐old WT, Sirt1 mesenchymal transgene ( Sirt1 Tg ), Cyp27b1 −/− , and Sirt1 Tg Cyp27b1 −/− mice were observed the pulmonary function, aging, and senescence‐associated secretory phenotype and TGF‐β1/IL‐11/MEK/ERK signaling. We found that pulmonary Sirt1 and serum vitamin D decreased with physiological aging, activating TGF‐β1/IL‐11/MEK/ERK signaling, and promoting senescence‐associated pulmonary fibrosis. Sirt1 overexpression improved pulmonary dysfunction, aging, DNA damage, senescence‐associated secretory phenotype, and fibrosis through downregulating TGF‐β1/IL‐11/MEK/ERK signaling in Cyp27b1 −/− mice. Sirt1 negatively regulated IL‐11 expression through deacetylating H3K9/14ac mainly at the region from −871 to −724 of IL‐11 promoter, also the major binding region of Smad2 which regulated IL‐11 expression at the transcriptional level, and subsequently inhibiting TGF‐β1/IL‐11/MEK/ERK signaling in pulmonary fibroblasts. This signaling in aging fibroblasts could be a therapeutic target for preventing senescence‐associated pulmonary fibrosis induced by vitamin D deficiency.
Osteoblastic lineage cells (OBCs) are bone-building cells and essential component of hematopoietic niche, but mechanisms whereby bone-building and hematopoiesis-supportive activities of OBCs could be regulated simultaneously remain largely unknown. Here we found that B cell-specific Moloney murine leukemia virus integration site 1 (Bmi1) was involved in such a co-regulatory mechanism. In this study, we first found that, accompanied with marked decline of osteogenic activity, the hematopoietic niche in Bmi1 knockout (KO) mice was severely impaired and manifested as CXCL12 expression falls and LSK homing failure; however, intratibial injection with CXCL12 effectively facilitated LSK accumulation in bone marrow of Bmi1 KO mice. To try to rescue these defects in Bmi1 KO mice, we generated Bmi1(KO)/Sirt1(Tg) (KO-TG) double mutant mice with Sirt1 specific overexpression in mesenchymal progenitor cells (MPCs) in Bmi1 KO mice, and our data showed that KO-TG mice had significantly increased bone-building activity, elevated Cxcl12 expression by MPCs, increased LSK homing and expanded LSK pool in bone marrow compared to Bmi1 KO mice. Of note, similar improvements in KO-TG mice were observed in Bmi1 KO mice fed with dietary resveratrol, an established Sirt1 activator, comparing with KO control mice. Therefore, pharmacologic activation of Bmi1/Sirt1 signaling pathway could simultaneously promote bone-building and hematopoiesis-supportive activities of OBCs.
人体解剖学是医学院校各专业新生学习的第一门医学基础课程,涉及专业广,学习人数多。将“课程思政”融入人体解剖学教学过程,有助于帮助医学生树立正确的科学道德观、生命伦理观,培养学生养成良好的医德医风与责任感,实现综合素质和专业能力的共同提高。因此,以人体解剖学心血管章节为例,从思政元素提炼、教学方案制定、教学效果反馈和教学效果评价这四方面探讨人体解剖学融合课程思政教学的可行性措施,为优化人体解剖学教学提供启示,以期实现知识传授与价值观引领有机统一。
Abstract Aims Senescence‐associated pathological cardiac hypertrophy (SA‐PCH) is associated with upregulation of foetal genes, fibrosis, senescence‐associated secretory phenotype (SASP), cardiac dysfunction and increased morbidity and mortality. Therefore, we conducted experiments to investigate whether GATA4 accumulation induces SA‐PCH, and whether Bmi‐1‐RING1B promotes GATA4 ubiquitination and its selective autophagic degradation to prevent SA‐PCH. Methods and results Bmi‐1‐deficient (Bmi‐1−/− ), transgenic Bmi‐1 overexpressing (Bmi‐1Tg ) and wild‐type (WT) mice were infused with angiotensin II (Ang II) to stimulate the development of SA‐PCH. Through bioinformatics analysis with RNA sequencing data from cardiac tissues, we found that Bmi‐1‐RING1B and autophagy are negatively related to SA‐PCH. Bmi‐1 deficiency promoted GATA4‐dependent SA‐PCH by increasing GATA4 protein and hypertrophy‐related molecules transcribed by GATA4 such as ANP and BNP. Bmi‐1 deficiency stimulated NF‐κB‐p65‐dependent SASP, leading to cardiac dysfunction, cardiomyocyte hypertrophy and senescence. Bmi‐1 overexpression repressed GATA4‐dependent SA‐PCH. GATA4 degraded by Bmi‐1 was mainly dependent on autophagy rather than proteasome. In human myocardium, p16 positively correlated with ANP and GATA4 and negatively correlated with LC3B, Bmi‐1 and RING1B; GATA4 positively correlated with p62 and negatively correlated with Bmi‐1 and LC3B. With increased p16 protein levels, ANP‐, BNP‐ and GATA4‐positive cells or areas increased; however, LC3B‐positive cells or areas decreased in human myocardium. GATA4 is ubiquitinated after combining with Bmi‐1‐RING1B, which is then recognised by p62, is translocated to autophagosomes to form autophagolysosomes and degraded. Downregulated GATA4 ameliorated SA‐PCH and cardiac dysfunction by reducing GATA4‐dependent hypertrophy and SASP‐related molecules. Bmi‐1 combined with RING1B (residues 1–179) and C‐terminus of GATA4 (residues 206–443 including zinc finger domains) through residues 1–95, including a RING‐HC‐finger. RING1B combined with C‐terminus of GATA4 through the C‐terminus (residues 180–336). Adeno‐associated viral vector serotype 9 (AAV9)‐cytomegalovirus (CMV)‐Bmi‐1‐RING1B treatment significantly attenuated GATA4‐dependent SA‐PCH through promoting GATA4 autophagic degradation. Conclusions Bmi‐1‐RING1B maintained cardiac function and prevented SA‐PCH by promoting selective autophagy for degrading GATA4. Translational perspective AAV9‐CMV‐Bmi‐1‐RING1B could be used for translational gene therapy to ubiquitinate GATA4 and prevent GATA4‐dependent SA‐PCH. Also, the combined domains between Bmi‐1‐RING1B and GATA4 in aging cardiomyocytes could be therapeutic targets for identifying stapled peptides in clinical applications to promote the combination of Bmi‐1‐RING1B with GATA4 and the ubiquitination of GATA4 to prevent SA‐PCH and heart failure. We found that degradation of cardiac GATA4 by Bmi‐1 was mainly dependent on autophagy rather than proteasome, and autophagy agonists metformin and rapamycin could ameliorate the SA‐PCH, suggesting that activation of autophagy with metformin or rapamycin could also be a promising method to prevent SA‐PCH.
Alcohol consumption is regarded as one of the leading risk factors for secondary osteopenia. Angiogenesis and osteogenesis coupled by type-H vessels coordinate the biological process of bone homeostasis to prevent osteopenia. This study aimed to determine whether chronic alcohol inhibits type-H vessel-dependent bone formation. Two-month-old mice were fed with 5% (v/v) alcohol liquid diet (28% of calories) or normal liquid diet every day for 2 months. The tibias were isolated and detected with X-ray and microcomputed tomography. Paraffin-embedded or frozen tibial sections were prepared and used for immunohistochemical or immunofluorescence staining, respectively. Human umbilical vein endothelial cells (HUVECs) were treated with different concentrations of alcohol, including 0 mM (0%), 8.7 mM (0.5%), 52 mM (3%), or 87 mM (5%) alcohol for 12 h. The conditioned medium of the above HUVEC cells was collected to culture human bone marrow-mesenchymal stem cells (BM-MSCs), which were induced to differentiate into osteoblasts in vitro. The alcoholic diet retarded the bone growth and led to osteoporosis, impaired bone formation of osteoblasts, and decreased CD31(hi)EMCN(hi) type-H vessel formation through inhibiting proliferation and promoting aging of endothelial cells in mice. Alcohol treatment obviously increased the expression of p16, while significantly decreased the expression of Bmi-1, CDK6, Cyclin D, E2F1, and bone morphogenetic protein (BMP)2 compared with vehicle. Alcohol inhibited the differentiation of BM-MSCs into osteoblasts through reducing the BMP2 secretion of endothelial cells in type-H vessels. Alcoholic diet impaired CD31(hi)EMCN(hi) type-H vessel formation through inhibiting proliferation and promoting aging of endothelial cells through Bmi-1/p16 signaling, and inhibited the differentiation of BM-MSCs into osteoblasts through reducing the BMP2 secretion of endothelial cells in type-H vessels. This study provides a basis for developing a new treatment strategy targeting aging endothelial cells of type-H vessel to prevent alcoholic osteopenia.