Loss of HMBOX1 promotes LPS-induced apoptosis and inhibits LPS-induced autophagy of vascular endothelial cells in mouse

Inhibition of Hmbox1 Promotes Cardiomyocyte Survival and Glucose Metabolism Through Gck Activation in Ischemia/Reperfusion Injury

BACKGROUND

Exercise-induced physiological cardiac growth regulators may protect the heart from ischemia/reperfusion (I/R) injury. Homeobox-containing 1 (Hmbox1), a homeobox family member, has been identified as a putative transcriptional repressor and is downregulated in the exercised heart. However, its roles in exercise-induced physiological cardiac growth and its potential protective effects against cardiac I/R injury remain largely unexplored.

METHODS

We studied the function of Hmbox1 in exercise-induced physiological cardiac growth in mice after 4 weeks of swimming exercise. Hmbox1 expression was then evaluated in human heart samples from deceased patients with myocardial infarction and in the animal cardiac I/R injury model. Its role in cardiac I/R injury was examined in mice with adeno-associated virus 9 (AAV9) vector-mediated Hmbox1 knockdown and in those with cardiac myocyte-specific Hmbox1 ablation. We performed RNA sequencing, promoter prediction, and binding assays and identified glucokinase (Gck) as a downstream effector of Hmbox1. The effects of Hmbox1 together with Gck were examined in cardiomyocytes to evaluate their cell size, proliferation, apoptosis, mitochondrial respiration, and glycolysis. The function of upstream regulator of Hmbox1, ETS1, was investigated through ETS1 overexpression in cardiac I/R mice in vivo.

RESULTS

We demonstrated that Hmbox1 downregulation was required for exercise-induced physiological cardiac growth. Inhibition of Hmbox1 increased cardiomyocyte size in isolated neonatal rat cardiomyocytes and human embryonic stem cell-derived cardiomyocytes but did not affect cardiomyocyte proliferation. Under pathological conditions, Hmbox1 was upregulated in both human and animal postinfarct cardiac tissues. Furthermore, both cardiac myocyte-specific Hmbox1 knockout and AAV9-mediated Hmbox1 knockdown protected against cardiac I/R injury and heart failure. Therapeutic effects were observed when sh-Hmbox1 AAV9 was administered after I/R injury. Inhibition of Hmbox1 activated the Akt/mTOR/P70S6K pathway and transcriptionally upregulated Gck, leading to reduced apoptosis and improved mitochondrial respiration and glycolysis in cardiomyocytes. ETS1 functioned as an upstream negative regulator of Hmbox1 transcription, and its overexpression was protective against cardiac I/R injury.

CONCLUSIONS

Our studies unravel a new role for the transcriptional repressor Hmbox1 in exercise-induced physiological cardiac growth. They also highlight the therapeutic potential of targeting Hmbox1 to improve myocardial survival and glucose metabolism after I/R injury.

Metabolomic analysis reveals the influence of HMBOX1 on RAW264.7 cells proliferation based on UPLC-MS/MS

Macrophages are important effector cells in tumor progression and immune regulation. Previously, we demonstrated that the transcription suppressor homeobox containing 1(HMBOX1) exhibits immunosuppressive activity in LPS-induced acute liver injury by impeding macrophage infiltration and activation. We also observed a lower proliferation in HMBOX1-overexpressed RAW264.7 cells. However, the specific mechanism was unclear. Here, a work was performed to characterize HMBOX1 function related to cell proliferation from a metabolomics standpoint by comparing the metabolic profiles of HMBOX1-overexpressed RAW264.7 cells to those of the controls. Firstly, we assessed HMBOX1 anti-proliferation activity in RAW264.7 cells with CCK8 assay and clone formation. Then, we performed metabolomic analyses by ultra-liquid chromatography coupled with mass spectrometry to explore the potential mechanisms. Our results indicated that HMBOX1 inhibited the macrophage growth curve and clone formation ability. Metabolomic analyses showed significant changes in HMBOX1-overexpressed RAW264.7 metabolites. A total of 1312 metabolites were detected, and 185 differential metabolites were identified based on the criterion of OPLS-DA VIP > 1 and p value < 0.05. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that the elevated HMBOX1 in RAW264.7 inhibited the pathways of amino acid and nucleotide metabolism. Glutamine concentrations decreased significantly in HMBOX1-overexpressed macrophages, and glutamine-related transporter SLC1A5 was also downregulated. Furthermore, SLC1A5 overexpression reversed HMBOX1 inhibition of macrophage proliferation. This study demonstrated the potential mechanism of the HMBOX1/SLC1A5 pathway in cell proliferation by regulating glutamine transportation. The results may help provide a new direction for therapeutic interventions in macrophage-related inflammatory diseases.

ptk2 and mt2a Genes Expression in Gastritis and Gastric Cancer Patients with Helicobacter pylori Infection

BACKGROUND

ptk2 and mt2a genes contribute to the cell cycle during proliferation and apoptosis, respectively. Designing a case-control study including gastric adenocarcinoma and gastritis patients with and without Helicobacter pylori infection would lead to determinate of the correlations between ptk2 and mt2a genes expression with H. pylori infection in gastric antral epithelial cells.

METHODS

Overall, 50 and 30 gastric antral biopsy samples of gastric cancer (case group) and gastritis (control group) patients were included into study, respectively. All biopsy samples were collected considering the exclusion criteria including patients with a history of consumption of tobacco, alcohol, and anti-H. pylori drugs. Each patient group is divided into with and without H. pylori infection to detect cDNA fold changes of ptk2 and mt2a genes by using Real Time RT PCR. Furthermore, the presence of H. pylori virulence genes was detected directly by using specific primers and simple PCR on cDNA synthesized from total RNA of gastric antral biopsy samples.

RESULTS

A negative correlation was revealed between age and clinical manifestations with the ΔCt value of the ptk2 gene (P < 0.05). The H. pylori iceA1/2 and cagE genes revealed positive and negative correlations with the ΔCt value of the ptk2 gene (P < 0.05), respectively. Furthermore, a weak correlation was detectable between H. pylori babA2/B, oipA, and cagY genes and the ΔCt value of the mt2a gene in gastric antral epithelial cells of patients (P < 0.1).

CONCLUSIONS

The results of the current study opened a view for more investigation on the stunning roles of H. pylori infection in clinical outcomes through mt2a and ptk2 gene expression in gastric antral epithelial cells.

Annexin A Protein Family in Atherosclerosis

Atherosclerosis, a silent chronic vascular pathology, is the cause of the majority of cardiovascular ischaemic events. Atherosclerosis is characterized by a series of deleterious changes in cellularity, including endothelial dysfunction, transmigration of circulating inflammatory cells into the arterial wall, pro-inflammatory cytokines production, lipid accumulation in the intima, vascular local inflammatory response, atherosclerosis-related cells apoptosis and autophagy. Proteins of Annexin A (AnxA) family, the well-known Ca²⁺ phospholipid-binding protein, have many functions in regulating inflammation-related enzymes and cell signaling transduction, thus influencing cell adhesion, migration, differentiation, proliferation and apoptosis. There is now accumulating evidence that some members of the AnxA family, such as AnxA1, AnxA2, AnxA5 and AnxA7, play major roles in the development of atherosclerosis. This article discusses the major roles of AnxA1, AnxA2, AnxA5 and AnxA7, and the multifaceted mechanisms of the main biological process in which they are involved in atherosclerosis. Considering these evidences, it has been proposed that AnxA are drivers- and not merely participator- on the road to atherosclerosis, thus the progression of atherosclerosis may be prevented by targeting the expression or function of the AnxA family proteins.

Exosome-Derived From Sepsis Patients' Blood Promoted Pyroptosis of Cardiomyocytes by Regulating miR-885-5p/HMBOX1

Background

Septic myocardial depression has been associated with increased morbidity and mortality. miR-885-5p has been shown to regulate cell growth, senescence, and/or apoptosis. Published studies demonstrated that Homeobox-containing protein 1 (HMBOX1) inhibits inflammatory response, regulates cell autophagy, and apoptosis. However, the role of miR-885-5p/HMBOX1 in sepsis and septic myocardial depression and the underlying mechanism is not fully understood.

Materials and Methods

Exosomes (exos) derived from sepsis patients (sepsis-exos) were isolated using ultracentrifugation. Rats were subjected to cecal ligation and puncture surgery and treated with sepsis-exos. HMBOX1 was knocked down or overexpressed in AC16 cells using lentiviral plasmids carrying short interfering RNAs targeting human HMBOX1 or carrying HMBOX1 cDNA. Cell pyroptosis was measured by flow cytometry. The secretion of IL-1β and IL-18 was examined by ELISA kits. Quantitative polymerase chain reaction (PCR) or western blot was used for gene expression.

Results

Sepsis-exos increased the level of miR-885-5p, decreased HMBOX1, elevated IL-1β and IL-18, and promoted pyroptosis in AC16 cells. Septic rats treated with sepsis-exos increased the serum inflammatory cytokines is associated with increased pyroptosis-related proteins of hearts. MiR-885-5p bound to the three prime untranslated regions of HMBOX1 to negatively regulate its expression. Overexpressing HMBOX1 reversed miR-885-5p-induced elevation of inflammatory cytokines and upregulation of NLRP3, caspase-1, and GSDMD-N in AC16 cells. The mechanistic study indicated that the effect of HMBOX1 was NF-κB dependent.

Conclusion

Sepsis-exos promoted the pyroptosis of AC16 cells through miR-885-5p via HMBOX1. The results show the significance of the miR-885-5p/HMBOX1 axis in myocardial cell pyroptosis and provide new directions for the treatment of septic myocardial depression.

HMBOX1 attenuates LPS-induced periodontal ligament stem cell injury by inhibiting CXCL10 expression through the NF-κB signaling pathway

Homeobox containing 1 (HMBOX1) is a member of the homeobox transcription factor family that has been reported to serve an important role in numerous biological processes. The present study aimed to determine the role of HMBOX1 in the pathogenesis of periodontitis. Human periodontal ligament stem cells (hPDLSCs) were treated with liposaccharide (LPS) and transfected with a HMBOX1 overexpression (Ov-HMBOX1) plasmid or small interfering (si)-C-X-C motif chemokine ligand 10 (CXCL10) plasmids. The effects of Ov-HMBOX1 on cell proliferation, inflammation and apoptosis were subsequently investigated using Cell Counting Kit-8, ELISA for analysis of IL-6, TNF-α and IL-1β levels, TUNEL and western blotting assays for analysis of Bcl-2, Bax, cleaved caspase-3 and caspase-3 levels, respectively. Furthermore, the potential effects of HMBOX1 on the mRNA and protein levels of CXCL10 and the NF-κB signaling pathway were investigated by using reverse transcription-quantitative PCR and western blotting. Finally, the physiological processes of lipopolysaccharide (LPS)-induced hPDLSCs overexpressing HMBOX1 were assessed following treatment with phorbol 12-myristate 13-acetate (PMA), a NF-κB agonist. The results revealed that Ov-HMBOX1 transfection promoted proliferation whilst alleviating inflammation and apoptosis in LPS-induced hPDLSCs. Ov-HMBOX1 reduced the expression of CXCL10 by suppressing the NF-κB signaling pathway. PMA treatment inhibited the proliferation of LPS-induced hPDLSCs transfected with Ov-HMBOX1, which was reversed by transfection with si-CXCL10. In conclusion, results of the present study provided evidence that HMBOX1 can attenuate LPS-induced hPDLSC injury by downregulating CXCL10 expression via the NF-κB signaling pathway, which may provide a novel insight into the development of potentially novel treatment strategies for periodontitis.

Expression of LncRNA DLGAP1-AS1 in a Mouse Model of Atherosclerosis and Its Effect on Oxidized Low-Density Lipoprotein-Induced Vascular Endothelial Cell Injury

The occurrence of vascular endothelial injury is key to the progression of atherosclerosis (AS). This research explores the expression of lncRNA DLGAP1-AS1 in a mouse model of atherosclerosis and its effect on ox-LDL-induced vascular endothelial cell injury. A mouse model of AS was constructed, and DLGAP1-AS1 expression was detected using the nano real-time PCR method. Vascular endothelial cells (VEC) are categorized into four groups. Flow cytometry detects cell apoptosis, and Western blot detects Bax and Bcl-2 expressions; WST-8 method detects level of SOD. Thiobarbituric acid method, Ammonium molybdate colorimetric method, DCFH-DA method were used to detect MDA, CAT, and reactive oxygen species (ROS) levels, respectively. Bioinformatics software predicted the target genes of DLGAP1-AS1. DLGAP1-AS1 expression was raised in AS mice, apoptotic rate and Bax expression in the ox-LDL group were raised, Bcl-2 expression was abated, MDA and ROS levels were raised, SOD and CAT levels were abated than in control. The si-DLGAP1-AS1+ox-LDL group decreased cell death and Bax expression, increased Bcl-2 expression, decreased MDA and ROS levels, and increased SOD and CAT levels than in the si-NC+ox-LDL group. Down-regulation of DLGAP1-AS1 was targeted in order to promote miR-26a-5p expression. Compared with co-transfection with DLGAP1-AS1 siRNA and inhibitor control, the apoptosis rate and Bax expression were increased after co-transfection with DLGAP1-AS1 siRNA and miR-26a-5p inhibitor, Bcl-2 expression was decreased, and MDA and ROS levels were increased, the level of SOD and CAT were decreased. DLGAP1-AS1 was up-regulated in AS mice and downregulated to promote miR-26a-5p to inhibit ox-LDL-induced vascular endothelial cell death and oxidative damage.

Procyanidin B2 inhibits lipopolysaccharide‑induced apoptosis by suppressing the Bcl‑2/Bax and NF‑κB signalling pathways in human umbilical vein endothelial cells

Human umbilical vein endothelial cells (HUVECs) serve a critical role in maintaining normal vascular function. Lipopolysaccharide (LPS), which is released from pathogenic bacteria in the blood, induces HUVEC apoptosis and injury to cause vascular dysfunction and infectious vascular diseases. Procyanidin B2 (PB2) possesses numerous functions, including antioxidant, antitumor, anti‑inflammatory and antiapoptosis effects, but the molecular mechanism is not completely understood. The present study investigated the effects of PB2 on LPS‑induced cytotoxicity and apoptosis in HUVECs, as well as the underlying mechanisms. The effects of PB2 on LPS‑mediated alterations to cytotoxicity, mitochondrial membrane potential, apoptosis were assessed by performing Cell Counting Kit‑8, JC‑1 fluorescence, Hoechst 33258 staining assays, respectively. IL‑1β, IL‑6 and TNF‑α mRNA expression and protein levels were measured by performing reverse transcription‑quantitative PCR and ELISAs, respectively. Bcl‑2, Bax, cleaved caspase‑3, cleaved caspase‑7, cleaved caspase‑9, phosphorylated (p)‑IκB‑α, p‑IκB‑β, p‑NF‑κB‑p65 and total NF‑κB p65 protein expression levels were determined via western blotting. NF‑κB p65 nuclear translocation was assessed via immunofluorescence. PB2 pretreatment markedly attenuated LPS‑induced cytotoxicity and apoptosis in HUVECs. PB2 also significantly downregulated the expression levels of IL‑1β, IL‑6, TNF‑α, Bax, cleaved caspase‑3, cleaved caspase‑7, cleaved caspase‑9 and p‑NF‑κB‑p65, but upregulated the expression levels of Bcl‑2, p‑IκB‑α and p‑IκB‑β in LPS‑induced HUVECs. Moreover, PB2 markedly inhibited LPS‑induced NF‑κB p65 nuclear translocation in HUVECs. The results suggested that the potential molecular mechanism underlying PB2 was associated with the Bax/Bcl‑2 and NF‑κB signalling pathways. Therefore, PB2 may serve as a useful therapeutic for infectious vascular diseases.

Sulforaphane protects human umbilical vein endothelial cells from oxidative stress via the miR-34a/SIRT1 axis by upregulating nuclear factor erythroid-2-related factor 2

Oxidative stress-induced vascular endothelial cell dysfunction serves an essential role in the initiation and development of atherosclerosis. Sulforaphane (SFN), a naturally occurring antioxidant, has previously demonstrated to exert protective effects on the endothelium against oxidative stress. However, further studies are required to determine its underlying molecular mechanism prior to clinical application. Accumulating evidence suggests that alterations in the microRNA (miRNA/miR)-34a/sirtuin-1 (SIRT1) axis occur with oxidative stress. Therefore, the present study aimed to investigate if SFN exerts a protective role against oxidative stress in vascular endothelial cells through regulation of the miR-34a/SIRT1 axis. Human umbilical vein endothelial cells (HUVECs) were treated with H₂O₂ in the presence or absence of SFN pretreatment. Cell viability and apoptosis were analyzed using CellTiter-Blue and flow cytometry, respectively. Reverse transcription-quantitative PCR and western blot analyses were performed to determine changes in the expression levels of miR-34a and SIRT1. The expression levels of miR-34a and SIRT1 were artificially regulated following transfection with miR-34a mimic and inhibitor or SIRT1expression plasmid and small interfering RNA, respectively. Subsequently, the effect of the expression changes of miR-34 and SIRT1 on oxidative stress-induced cell injury was investigated. Dual-luciferase reporter assay was used to confirm the targeted binding of miR-34a to SIRT1. SFN was found to ameliorate cellular damage caused by H₂O₂ and inhibited intracellular reactive oxygen species production. In addition, miR-34a upregulation was accompanied with reduced SIRT1 expression in HUVECs, following H₂O₂ treatment. miR-34a was revealed to directly target SIRT1 by binding to its 3'-untranslated region. Down-regulation of miR-34a and up-regulation of SIRT1 increased the survival of HUVECs under oxidative stress. Taken together, the results of the present study suggest that SFN may protect HUVECs from oxidative stress by inducing changes in the miR-34a/SIRT1 axis via upregulation of nuclear factor erythroid-2-related factor 2 expression.