Nicotinamide N-Methyltransferase (NNMT) is Involved in Gastric Adenocarcinoma Immune Infiltration by Driving Amino Acid Metabolism.

Objectives: This study investigates the role of Nicotinamide N-methyltransferase (NNMT) in immune infiltration modulation through amino acid metabolism in gastric adenocarcinoma (STAD). Methods: Utilizing data from The Cancer Genome Atlas (TCGA) and validated with clinical samples, we analyzed NNMT expression and its prognostic implications in STAD. Differential amino acid profiles between cancerous and adjacent normal tissues were assessed, along with their associations with NNMT. Results: NNMT exhibits heightened expression in STAD cancer tissues, positively correlating with tumor immune infiltration. Additionally, twenty-eight amino acids display differential expression in gastric tissue, with their metabolic enzymes showing connections to NNMT. Conclusions: Elevated NNMT expression in STAD tissues potentially influences amino acid metabolism, thereby affecting immune infiltration dynamics and tumorigenesis in gastric adenocarcinoma.

Sustainability of exercise-induced benefits on circulating MicroRNAs and physical fitness in community-dwelling older adults: a randomized controlled trial with follow up.

BACKGROUND: Circulating miRNAs (c-miR) have been shown to be potential biomarkers in sarcopenia, but the miRNAs response to aerobic exercise in older people remains inconclusive. We sought to examine the exercise benefits on physical fitness and miRNAs, and to explore the mediating effect of miRNAs on training-induced fitness changes. METHODS: This controlled trial recruited 58 community-dwelling older adults and randomized them into exercise group (EX) and control group (CON). EX received 8-week supervised moderate intensity cycling training 3x/week. C-miR expression (c-miR-21, c-miR-126, c-miR-146a, c-miR-222), physical fitness (body composition, cardiorespiratory fitness, muscular fitness) and physical activity level (PAL, measured as in daily step counts) were evaluated at baseline, post-training, and post-16-week follow-up. The mediating effect of miRNA expression onto exercise-induced physical fitness change was determined by causal mediation analysis (CMA). RESULTS: Exercise significantly improved body fat and cardiorespiratory fitness in older people while maintaining muscle mass and strength, and augmented expression of c-miR-126, c-miR-146a, and c-miR-222 for up to 16 weeks post-training. Notably, older people in EX had substantially higher daily step counts than CON throughout the study even after the active training period. However, CMA revealed no significant indirect effect but a potential mediating effect of c-miR-21, but not the rest, onto the body composition, cardiorespiratory fitness, and lower limb strength. CONCLUSION: An eight-week supervised MICT program promoted a higher level of physical activity up to 16 weeks post-training, which induces better cardiorespiratory fitness and resists decline in muscular measures. C-miRNA, especially c-miR-21, potentially mediates the training effect upon fitness.

Synergistic suppression of BDNF via epigenetic mechanism deteriorating learning and memory impairment caused by Mn and Pb co-exposure.

Microglia, the resident immune cells of the central nervous system (CNS), play a dual role in neurotoxicity by releasing the NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome and brain-derived neurotrophic factor (BDNF) in response to environmental stress. Suppression of BDNF is implicated in learning and memory impairment induced by exposure to manganese (Mn) or lead (Pb) individually. Methyl CpG Binding Protein 2 (MeCp2) and its phosphorylation status are related to BDNF suppression. Protein phosphatase2A (PP2A), a member of the serine/threonine phosphatases family, dephosphorylates substrates based on the methylation state of its catalytic C subunit (PP2Ac). However, the specific impairment patterns and molecular mechanisms resulting from co-exposure to Mn and Pb remain unclear. Therefore, the purpose of this study was to explore the effects of Mn and Pb exposure, alone and in combination, on inducing neurotoxicity in the hippocampus of mice and BV2 cells, and to determine whether simultaneous exposure to both metals exacerbate their toxicity. Our findings reveal that co-exposure to Mn and Pb leads to severe learning and memory impairment in mice, which correlates with the accumulation of metals in the hippocampus and synergistic suppression of BDNF. This suppression is accompanied by up-regulation of the epigenetic repressor MeCp2 and its phosphorylation status, as well as demethylation of PP2Ac. Furthermore, inhibition of PP2Ac demethylation using ABL127, an inhibitor for its protein phosphatase methylesterase1 (PME1), or knockdown of MeCp2 via siRNA transfection in vitro effectively increases BDNF expression and mitigates BV2 cell damage induced by Mn and Pb co-exposure. We also observe abnormal activation of microglia characterized by enhanced release of the NLRP3 inflammasome, Casepase-1 and pro-inflammatory cytokines IL-1ß, in the hippocampus of mice and BV2 cells. In summary, our experiments demonstrate that simultaneous exposure to Mn and Pb results in more severe hippocampus-dependent learning and memory impairment, which is attributed to epigenetic suppression of BDNF mediated by PP2A regulation.

Identification of Vernonia patula Merr. and Its Similar Varieties Based on a Combination of HPLC Fingerprinting and Chemical Pattern Recognition.

Vernonia patula Merr. (VP) is a traditional medicine used by the Zhuang and Yao people, known for its therapeutic properties in treating anemopyretic cold and other diseases. Distinguishing VP from similar varieties such as Praxelis clematidea (PC), Ageratum conyzoides L. (AC) and Ageratum houstonianum Mill (AH) was challenging due to their similar traits and plant morphology. The HPLC fingerprints of 40 batches of VP and three similar varieties were established. SPSS 20.0 and SIMCA-P 13.0 were used to statistically analyze the chromatographic peak areas of 37 components. The results showed that the similarity of the HPLC fingerprints for each of the four varieties was >0.9, while the similarity between the control chromatogram of VP and its similar varieties was <0.678. Cluster analysis and partial least squares discriminant analysis provided consistent results, indicating that all four varieties could be individually clustered together. Through further analysis, we found isochlorogenic acid A and isochlorogenic acid C were present only in the original VP, while preconene II was present in the three similar varieties of VP. These three components are expected to be identification points for accurately distinguishing VP from PC, AC and AH.

RNA m5C methylation orchestrates BLCA progression via macrophage reprogramming.

Recently, epigenetics showed essential roles in tumour microenvironment (TME) and immunotherapy response, however, the functions of RNA 5-methylcytosine (m5C) modification in TME remains unknown. According to 13 m5C regulators, we evaluated 412 BLCA patients from The Cancer Genome Atlas (TCGA) database. The m5C score was constructed by unsupervised clustering analysis and principal component analysis (PCA) algorithms. Gene set variation analysis (GSVA), ESTIMATE algorithm, and immunohistochemical (IHC) staining were performed. Macrophage chemotaxis assay was used to assess the M2 macrophages. Among the 412 patients, the frequency of mutation was 13%. m5C regulators was expressed significantly in BLCA tissue compared with normal tissue. Then, two m5C methylation modification patterns were identified with dissimilar TME cell infiltration patterns. The C1 alteration pattern in the m5C cluster was connected with better survival. In addition, we found that NSUN6 was highly correlated with recruitment of macrophages via bioinformatics and IHC. Further experiment validated that NSUN6 promoted HDAC10 expression by mediating m5C methylation, inhibited the transcription of macrophage-associated chemokines and thus inhibited the recruitment of M2 macrophages. The m5C score constructed by m5C modification pattern showed that high m5C score group had a better prognosis. This study uncovered the significant roles of m5C modifications in modulating the TME and indicated that NSUN6 could inhibit the recruitment of M2 macrophages via m5C methylation, which provided novel insight into epigenetic regulation of TME and clinical suggestions for immunotherapeutic strategies.

Transcranial alternating current stimulation for treating depression: a randomized controlled trial.

Treatment of depression with antidepressants is partly effective. Transcranial alternating current stimulation can provide a non-pharmacological alternative for adult patients with major depressive disorder. However, no study has used the stimulation to treat first-episode and drug-naïve patients with major depressive disorder. We used a randomized, double-blind, sham-controlled design to examine the clinical efficacy and safety of the stimulation in treating first-episode drug-naïve patients in a Chinese Han population. From 4 June 2018 to 30 December 2019, 100 patients were recruited and randomly assigned to receive 20 daily 40-min, 77.5 Hz, 15 mA, one forehead and two mastoid sessions of active or sham stimulation (n = 50 for each group) in four consecutive weeks (Week 4), and were followed for additional 4-week efficacy/safety assessment without stimulation (Week 8). The primary outcome was a remission rate defined as the 17-item Hamilton Depression Rating Scale (HDRS-17) score ≤ 7 at Week 8. Secondary analyses were response rates (defined as a reduction of ≥ 50% in the HDRS-17), changes in depressive symptoms and severity from baseline to Week 4 and Week 8, and rates of adverse events. Data were analysed in an intention-to-treat sample. Forty-nine in the active and 46 in the sham completed the study. Twenty-seven of 50 (54%) in the active treatment group and 9 of 50 (18%) in the sham group achieved remission at the end of Week 8. The remission rate was significantly higher in the active group compared to that in the sham group with a risk ratio of 1.78 (95% confidence interval, 1.29, 2.47). Compared with the sham, the active group had a significantly higher remission rate at Week 4, response rates at Weeks 4 and 8, and a larger reduction in depressive symptoms from baseline to Weeks 4 and 8. Adverse events were similar between the groups. In conclusion, the stimulation on the frontal cortex and two mastoids significantly improved symptoms in first-episode drug-naïve patients with major depressive disorder and may be considered as a non-pharmacological intervention for them in an outpatient setting.

Genome-Scale Analysis of the Grapevine KCS Genes Reveals Its Potential Role in Male Sterility.

Very long-chain fatty acid (VLCFA) synthesis in plants, is primarily rate-limited by the enzyme 3-ketoacyl CoA synthase (KCS), which also controls the rate and carbon chain length of VLCFA synthesis. Disruption of VLCFA during pollen development, may affect the pollen wall formation and ultimately lead to male sterility. Our study identified 24 grapevine KCS (VvKCS) genes and provided new names based on their relative chromosome distribution. Based on sequence alignment and phylogenetic investigation, these genes were grouped into seven subgroups, members of the same subgroup having similar motif structures. Synteny analysis of VvKCS genes, showed that the segmental duplication events played an important role in expanding this gene family. Expression profiles obtained from the transcriptome data showed different expression patterns of VvKCS genes in different tissues. Comparison of transcriptome and RT-qPCR data of the male sterile grape 'Y-14' and its fertile parent 'Shine Muscat', revealed that 10 VvKCS genes were significantly differentially expressed at the meiosis stage, which is a critical period of pollen wall formation. Further, joint analysis by weighted gene co-expression network analysis (WGCNA) and Kyoto Encyclopedia of Genes and Genomes (KEGG), revealed that five of these VvKCS (VvKCS6/15/19/20/24) genes were involved in the fatty acid elongation pathway, which may ultimately affect the structural integrity of the pollen wall in 'Y-14'. This systematic analysis provided a foundation for further functional characterization of VvKCS genes, with the aim of grapevine precision breeding improvement.

Tri-zone flame spatial structure imaging combined with endogenic polarized scattering.

We propose a multi-mode optical imaging method to retrieve the 2D and 3D spatial structures of the preheating, reaction, and recombination zones of an axisymmetric steady flame. In the proposed method, an infrared camera, a visible light monochromatic camera, and a polarization camera are triggered synchronously to capture 2D flame images, and their corresponding 3D images are reconstructed by combining different projection position images. The results of the experiments conducted indicate that the infrared and visible light images represent the flame preheating and flame reaction zones, respectively. The polarized image can be obtained by computing the degree of linear polarization (DOLP) of raw images captured by the polarization camera. We discover that the highlighted regions in the DOLP images lie outside the infrared and visible light zones; they are insensitive to the flame reaction and have different spatial structures for different fuels. We deduce that the combustion product particles cause endogenic polarized scattering, and that the DOLP images represent the flame recombination zone. This study focuses on the combustion mechanisms, such as the formation of combustion products and quantitative flame composition and structure.

Leveraging Transfer Learning and Chemical Principles toward Interpretable Materials Properties.

Machine learning is emerging as a new paradigm to rationalize chemical properties for deepening our understanding of chemistry and providing instructive clues on better materials performance. While the complex architecture of machine learning contributes to unprecedented capability in this task, it prevents easy interpretation, leading to extensive criticisms on the lack of physical foundations for the black-box like models. Here, we demonstrate a transfer learning strategy that leverages fundamental principles of chemistry to offer adequate physical insights for the interpretation. Through interpreting the models for the formation energies of inorganic compounds, the proposed strategy revealed the deficiency of deep neural network in handling interelemental patterns and proved the more proper abstraction of recurrent neural network with attention mechanism, which led to predicting the elegant form of periodic table with high precision. The success demonstrates a new solution toward models with full transparency in materials informatics.

Yes-associated protein promotes tumour necrosis factor α-treated cementoblast mineralization partly by inactivating NF-κB pathway.

Cementum regeneration, as one of the most difficult challenges of periodontal regeneration, is influenced by inflammatory factors. Inflammation may hamper or promote periodontal tissue repair under different circumstances, as it is found to do in dentin-pulp complex and bone tissue. Our team demonstrated that YAP promotes mineralization of OCCM, a cementoblast cell line. However, the effect of YAP on its mineralization under inflammatory microenvironment is unclear. In this study, cementogenesis in vitro was up-regulated after transient TNF-α treatment for 30 minutes. YAP expression also was increased by TNF-α treatment. YAP overexpression promoted OCCM mineralization after the cells were transiently treated with TNF-α because YAP overexpression inhibited NF-κB pathway activity, while YAP knockdown elevated it. The inhibited mineralization potential and activated NF-κB pathway activity by YAP knockdown also were partly rescued by the application of the NF-κB inhibitor Bay 11-7082. These results demonstrated that YAP plays a positive role in the mineralization of TNF-α transiently treated cementoblast, partly by inhibiting the NF-κB pathway activity.

Identification and characterization of antioxidant peptides from Chinese dry-cured mutton ham.

BACKGROUND: Chinese mutton ham is a dry-cured meat product with a long ripening time. The aim of this study was to identify and characterize antioxidant peptides from Chinese mutton ham. RESULTS: Mutton ham peptides (MHPs) were purified by gel filtration, anion exchange and reversed-phase high-performance liquid chromatography steps. The 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) free radical scavenging capacity was used to guide the purification of MHPs. Three antioxidant peptides were identified by liquid chromatography with tandem mass spectrometry (LC-MS/MS) as Met-Trp-Thr-Asp (MWTD), Ala-Pro-Tyr-Met-Met (APYMM) and Phe-Trp-Ile-Ile-Glu (FWIIE), with molecular weights 551.61, 611.76, and 706.84 Da, respectively. Among them, APYMM exhibited the highest ABTS radical scavenging activity. The three peptides had the ability to inhibit lipid oxidation and Fenton's reagent-induced protein oxidation and DNA damage. After simulated gastrointestinal digestion, FWIIE and APYMM showed increased antioxidant activity, while MWTD showed decreased activity. CONCLUSION: Three novel peptides isolated from Chinese mutton ham had strong biological activity. Chinese mutton ham is potentially a functional food and an excellent source of natural antioxidants. © 2019 Society of Chemical Industry.

SIRT6 overexpression inhibits cementogenesis by suppressing glucose transporter 1.

Cementum, which shares common features with bone in terms of biochemical composition, is important for the homeostasis of periodontium during periodontitis and orthodontic treatment. Sirtuin 6 (SIRT6), as a member of the sirtuin family, plays key roles in the osteogenic differentiation of bone marrow mesenchymal stem cells. However, the involvement of SIRT6 in cementoblast differentiation and mineralization and the underlying mechanisms remain unknown. In this study, we observed that the expression of SIRT6 increased during cementoblast differentiation initially. Analysis of the gain- and loss-of-function indicated that overexpressing SIRT6 in OCCM-30 cells suppresses cementoblast differentiation and mineralization and downregulating SIRT6 promotes cementogenesis. GLUT1, a glucose transporter necessary in cementogenesis, was inhibited by SIRT6. Overexpressing GLUT1 in SIRT6-overexpressed OCCM-30 cells rescued the inhibitory effect of SIRT6 on cementoblast differentiation and mineralization. Moreover, AMPK was activated after overexpressing SIRT6 and inhibited cementoblast differentiation and mineralization. Downregulating the expression of SIRT6 inhibited AMPK activity. Meanwhile, GLUT1 overexpression significantly decreased AMPK activity. Overall, on one hand, SIRT6 inhibited cementoblast differentiation and mineralization by suppressing GLUT1. On the other hand, SIRT6 inhibited cementoblast differentiation and mineralization by activating the AMPK pathway. GLUT1 overexpression also rescued the increased AMPK pathway activated by SIRT6.

The E3 ubiquitin ligase RNF185 facilitates the cGAS-mediated innate immune response.

The cyclic GMP-AMP synthase (cGAS), upon cytosolic DNA stimulation, catalyzes the formation of the second messenger 2'3'-cGAMP, which then binds to stimulator of interferon genes (STING) and activates downstream signaling. It remains to be elucidated how the cGAS enzymatic activity is modulated dynamically. Here, we reported that the ER ubiquitin ligase RNF185 interacted with cGAS during HSV-1 infection. Ectopic-expression or knockdown of RNF185 respectively enhanced or impaired the IRF3-responsive gene expression. Mechanistically, RNF185 specifically catalyzed the K27-linked poly-ubiquitination of cGAS, which promoted its enzymatic activity. Additionally, Systemic Lupus Erythematosus (SLE) patients displayed elevated expression of RNF185 mRNA. Collectively, this study uncovers RNF185 as the first E3 ubiquitin ligase of cGAS, shedding light on the regulation of cGAS activity in innate immune responses.

Subacute combined degeneration of the spinal cord is associated with tripterygium glycoside tablet usage.

BACKGROUND: Subacute combined degeneration (SCD) is a neurodegenerative disease caused by vitamin B12 deficiency. The lesions mainly involve the posterior cord, lateral cord, and peripheral nerves. Occasionally, the lesions also involve brain white matter and optic nerves in severe cases. Reports of drug-induced impaired absorption and metabolism of vitamin B12 resulting in SCD are scarce. INTRODUCTION: A patient developed SCD after long-term use of tripterygium glycoside tablets in the treatment of glomerulonephritis. However, after discontinuation and vitamin B12 treatment with tripterygium glycoside tablet, the symptoms of SCD were significantly resolved. CONCLUSION: Drug-induced SCD is a less commonly reported cause of the disease. Tripterygium glycoside tablets can induce adverse reactions in the digestive system, causing damage to absorption and metabolism of vitamin B12. Physicians should be aware of the possibility of tripterygium glycoside tablet-induced SCD after excluding more common causes such as inadequate dietary intake and impaired absorption due to gastrointestinal diseases or genetic disorders.

IRX5 promotes NF-κB signalling to increase proliferation, migration and invasion via OPN in tongue squamous cell carcinoma.

Iroquois homeobox gene 5 (Irx5) is a highly conserved member of the Iroquois homeobox gene family. Members of this family play distinct and overlapping roles in normal embryonic cell patterning and development of malignancies. In this study, we observed that IRX5 was abnormally abundant in tongue squamous cell carcinoma (TSCC) tissues and cell lines. We used gain- and loss-of-function methods to overexpress and knockdown IRX5 expression in the TSCC cell line CAL27. Our results elucidated that elevated levels of IRX5 promoted proliferation, migration and invasion of TSCC cells, whereas stable or transient knockdown of IRX5 expression suppressed TSCC cell proliferation, migration and invasion. As a transcription factor, IRX5 performed this function by targeting osteopontin (OPN) promoter and activating the NF-κB pathway. Finally, studies in xenograft tumour model showed that IRX5 significantly enhanced OPN expression and promoted tumour growth. Taken together, our study elucidates a promotive effect of IRX5 in TSCC through the connection with OPN. These findings reveal the new molecular mechanism of TSCC, which may potentiate its use as a novel molecular therapy target for TSCC.

The cost of Alzheimer's disease in China and re-estimation of costs worldwide.

INTRODUCTION: The socioeconomic costs of Alzheimer's disease (AD) in China and its impact on global economic burden remain uncertain. METHODS: We collected data from 3098 patients with AD in 81 representative centers across China and estimated AD costs for individual patient and total patients in China in 2015. Based on this data, we re-estimated the worldwide costs of AD. RESULTS: The annual socioeconomic cost per patient was US $19,144.36, and total costs were US $167.74 billion in 2015. The annual total costs are predicted to reach US $507.49 billion in 2030 and US $1.89 trillion in 2050. Based on our results, the global estimates of costs for dementia were US $957.56 billion in 2015, and will be US $2.54 trillion in 2030, and US $9.12 trillion in 2050, much more than the predictions by the World Alzheimer Report 2015. DISCUSSION: China bears a heavy burden of AD costs, which greatly change the estimates of AD cost worldwide.

[Effectiveness of an Interdisciplinary Health Education Intervention on Metabolic Syndrome in Community Residents: A Study of Four Towns in Northern Taiwan].

BACKGROUND: Metabolic syndrome, a widespread condition in Taiwan, increases the risks of cardiovascular diseases. Cardiovascular disease is the second leading cause of death in Taiwan after cancer. Thus, this health problem is a priority issue of concern. PURPOSE: To study the effects of active intervention of interdisciplinary health education on the prevalence of metabolic syndrome in community residents. METHODS: This longitudinal study was conducted from 2014 to 2015 on 661 participants who were all over 30 years old and living in four towns in northern Taiwan. The data were collected into two steps. In the first step, participants completed a blood study, body measurement, and pretest questionnaires and participated in the entire course of metabolic syndrome health education. The results of the blood test and body measurement were blinded to the experienced metabolic physicians before and after the education courses. In the second step, one year after administering the interdisciplinary health education course, the participants repeated the blood study, body measurement, and posttest questionnaires. RESULTS: 1. The participants had a higher incidence of metabolic syndrome. However, gender and marital status had no significant correlation with metabolic syndrome. Higher education levels were associated with a lower prevalence of metabolic syndrome. 2. The average scores for literacy rose from 2.30 pretest to 5.65 posttest. There were significant correlations (p < .05) between pretest and posttest health education. 3. The diagnosis of metabolic syndrome in this study changed from 215 participants (32.5%) to 170 participants (25.7%) between pretest and posttest (p < .05). 4. active health education had significant and positive effects on the cessation of smoking and chewing betel nut (p <.05). CONCLUSIONS: The active interdisciplinary health education intervention used in this study significantly decreased the smoking and betel-nut chewing habits and decreased the overall risk of metabolic syndrome in participants. Therefore, providing active health education on metabolic syndrome holds the potential to significantly decrease the prevalence of metabolic syndrome in at-risk populations. In addition, healthcare providers should make appropriately targeted health education more accessible to elderly patients who are prone to metabolic syndrome. Finally, the cessation of chewing betel nut should be seen as a major factor in the prevention and alleviation of metabolic syndrome.

Pannexin3 inhibits TNF-α-induced inflammatory response by suppressing NF-κB signalling pathway in human dental pulp cells.

Human dental pulp cells (HDPCs) play a crucial role in dental pulp inflammation. Pannexin 3 (Panx3), a member of Panxs (Pannexins), has been recently found to be involved in inflammation. However, the mechanism of Panx3 in human dental pulp inflammation remains unclear. In this study, the role of Panx3 in inflammatory response was firstly explored, and its potential mechanism was proposed. Immunohistochemical staining showed that Panx3 levels were diminished in inflamed human and rat dental pulp tissues. In vitro, Panx3 expression was significantly down-regulated in HDPCs following a TNF-α challenge in a concentration-dependent way, which reached the lowest level at 10 ng/ml of TNF-α. Such decrease could be reversed by MG132, a proteasome inhibitor. Unlike MG132, BAY 11-7082, a NF-κB inhibitor, even reinforced the inhibitory effect of TNF-α. Quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to investigate the role of Panx3 in inflammatory response of HDPCs. TNF-α-induced pro-inflammatory cytokines, interleukin (IL)-1ß and IL-6, were significantly lessened when Panx3 was overexpressed in HDPCs. Conversely, Panx3 knockdown exacerbated the expression of pro-inflammatory cytokines. Moreover, Western blot, dual-luciferase reporter assay, immunofluorescence staining, qRT-PCR and ELISA results showed that Panx3 participated in dental pulp inflammation in a NF-κB-dependent manner. These findings suggested that Panx3 has a defensive role in dental pulp inflammation, serving as a potential target to be exploited for the intervention of human dental pulp inflammation.

The Role of Pannexin3-Modified Human Dental Pulp-Derived Mesenchymal Stromal Cells in Repairing Rat Cranial Critical-Sized Bone Defects.

BACKGROUND/AIMS: Human dental pulp-derived mesenchymal stromal cells (hDPSCs) are promising seed cells for tissue engineering due to their easy accessibility and multi-lineage differentiation. Pannexin3 (Panx3) plays crucial roles during bone development and differentiation. The aim of the present study was to investigate the effect of Panx3 on osteogenesis of hDPSCs and the underlying mechanism. METHODS: Utilizing qRT-PCR, Western blot, and immunohistochemistry, we explored the change of Panx3 during osteogenic differentiation of hDPSCs. Next, hDPSCs with loss (Panx3 knockdown) and gain (Panx3 overexpression) of Panx3 function were developed to investigate the effects of Panx3 on osteogenic differentiation of hDPSC and the underlying mechanism. Finally, a commercial ß-TCP scaffold carrying Panx3-modified hDPSCs was utilized to evaluate bone defect repair. RESULTS: Panx3 was upregulated during osteogenic differentiation in a time-dependent manner. Panx3 overexpression promoted osteogenic differentiation of hDPSCs, whereas depletion of Panx3 resulted in a decline of differentiation, evidenced by upregulated expression of mineralization-related markers, increased alkaline phosphatase (ALP) activity, and enhanced ALP and Alizarin red staining. Panx3 was found to interact with the Wnt/ß-catenin signaling pathway, forming a negative feedback loop. However, Wnt/ß-catenin did not contribute to enhancement of osteogenic differentiation as observed in Panx3 overexpression. Moreover, Panx3 promoted osteogenic differentiation of hDPSCs via increasing ERK signaling pathway. Micro-CT and histological staining results showed that Panx3-modified hDPSCs significantly improved ossification of critical-sized bone defects. CONCLUSION: These findings suggest that Panx3 is a crucial modulator of hDPSCs differentiation.

Pyruvate kinase M2 interacts with mammalian sterile 20-like kinase 1 and inhibits tamoxifen-induced apoptosis in human breast cancer cells.

Tamoxifen has been reported to be associated with antagonism of estrogen-mediated cell growth signaling and activation of estrogen receptor-independent apoptosis events. It has been demonstrated that mammalian sterile 20-like kinase 1 is a direct target of Caspases to amplify the apoptotic signaling pathway. Here, we presented that breast cancer MCF-7 and SKBR3 cells under treatment with 4-hydroxytamoxifen displayed decreased level of pyruvate kinase M2. Western blot results also showed that 4-hydroxytamoxifen induced the activity of pro-apoptotic protein Caspase-3 in MCF-7 and SKBR3 cells, as evidenced by the cleavage of mammalian sterile 20-like kinase 1 substrate in a dose-dependent manner. Co-immunoprecipitation and immunofluorescence experiments were performed to clarify the relationship between pyruvate kinase M2 and mammalian sterile 20-like kinase 1. The results indicated that mammalian sterile 20-like kinase 1 was associated with pyruvate kinase M2 in cultured mammalian cells, and the interaction between mammalian sterile 20-like kinase 1 and pyruvate kinase M2 was decreased in response to 4-hydroxytamoxifen treatment. In addition, knockdown of pyruvate kinase M2 upregulated the level of cleaved Caspase-3 and subsequently facilitated the nuclear translocation of mammalian sterile 20-like kinase 1. Our data further supplemented the extensive functions of pyruvate kinase M2 in mediating breast cancer cell viability by substantially abating the mammalian sterile 20-like kinase 1-mediated apoptosis. In summary, our results identified that mammalian sterile 20-like kinase 1 is a novel downstream target of pyruvate kinase M2, and knockdown of pyruvate kinase M2 contributes apoptosis via promoting nuclear translocation of mammalian sterile 20-like kinase 1 by enhancing Caspase-3-dependent cleavage.