YAP and TAZ play oncogenic roles in various organs, but the role of YAP/TAZ in gastric cancer remains unclear. Here, we show that YAP/TAZ activation initiates gastric tumorigenesis
and verify its ...significance in human gastric cancer. In mice, YAP/TAZ activation in the pyloric stem cell led to step-wise tumorigenesis. RNA sequencing identified MYC as a decisive target of YAP, which controls MYC at transcriptional and posttranscriptional levels. These mechanisms tightly regulated MYC in homeostatic conditions, but YAP activation altered this balance by impeding miRNA processing, causing a shift towards MYC upregulation. Pharmacologic inhibition of MYC suppressed YAP-dependent phenotypes
and
, verifying its functional role as a key mediator. Human gastric cancer samples also displayed a significant correlation between YAP and MYC. We reanalyzed human transcriptome data to verify enrichment of YAP signatures in a subpopulation of gastric cancers and found that our model closely reflected the molecular pattern of patients with high YAP activity. Overall, these results provide genetic evidence of YAP/TAZ as oncogenic initiators and drivers for gastric tumors with MYC as the key downstream mediator. These findings are also evident in human gastric cancer, emphasizing the significance of YAP/TAZ signaling in gastric carcinogenesis.
YAP/TAZ activation initiates gastric carcinogenesis with MYC as the key downstream mediator.
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Autophagy maintains cellular homeostasis during low energy states. According to the current understanding, glucose-depleted cells induce autophagy through AMPK, the primary energy-sensing kinase, to ...acquire energy for survival. However, contrary to the prevailing concept, our study demonstrates that AMPK inhibits ULK1, the kinase responsible for autophagy initiation, thereby suppressing autophagy. We found that glucose starvation suppresses amino acid starvation-induced stimulation of ULK1-Atg14-Vps34 signaling via AMPK activation. During an energy crisis caused by mitochondrial dysfunction, the LKB1-AMPK axis inhibits ULK1 activation and autophagy induction, even under amino acid starvation. Despite its inhibitory effect, AMPK protects the ULK1-associated autophagy machinery from caspase-mediated degradation during energy deficiency, preserving the cellular ability to initiate autophagy and restore homeostasis once the stress subsides. Our findings reveal that dual functions of AMPK, restraining abrupt induction of autophagy upon energy shortage while preserving essential autophagy components, are crucial to maintain cellular homeostasis and survival during energy stress.
Angiogenesis is a multistep process that requires coordinated migration, proliferation, and junction formation of vascular endothelial cells (ECs) to form new vessel branches in response to growth ...stimuli. Major intracellular signaling pathways that regulate angiogenesis have been well elucidated, but key transcriptional regulators that mediate these signaling pathways and control EC behaviors are only beginning to be understood. Here, we show that YAP/TAZ, a transcriptional coactivator that acts as an end effector of Hippo signaling, is critical for sprouting angiogenesis and vascular barrier formation and maturation. In mice, endothelial-specific deletion of Yap/Taz led to blunted-end, aneurysm-like tip ECs with fewer and dysmorphic filopodia at the vascular front, a hyper-pruned vascular network, reduced and disarranged distributions of tight and adherens junction proteins, disrupted barrier integrity, subsequent hemorrhage in growing retina and brain vessels, and reduced pathological choroidal neovascularization. Mechanistically, YAP/TAZ activates actin cytoskeleton remodeling, an important component of filopodia formation and junction assembly. Moreover, YAP/TAZ coordinates EC proliferation and metabolic activity by upregulating MYC signaling. Overall, these results show that YAP/TAZ plays multifaceted roles for EC behaviors, proliferation, junction assembly, and metabolism in sprouting angiogenesis and barrier formation and maturation and could be a potential therapeutic target for treating neovascular diseases.
The provision of distance education has increased rapidly over the past few years owing to the COVID-19 pandemic. The core of gross anatomy distance education is three-dimensional (3D) visualization ...of anatomical structures, and the use of simple 3D visualization tools has increased as distance education has become more popular. The purpose of this study was to establish a more effective operation plan in dental hygiene by investigating learners' opinions about distance education of gross anatomy and 3D visualization tools, and by comparing and analyzing their academic achievements. The study involved 250 students and comprised an analysis of 120 students who took a head and neck anatomy class at the Department of Dental Hygiene at D University via distance learning during 2020-2022, and 130 graduates who had completed the class via face-to-face learning during 2015-2017. An online survey of 120 of the enrolled students comprised 10 questions asking for opinions on the head and neck anatomy distance learning classes, five questions on the 3D visualization tool, and five on general characteristics. Overall, the learners had positive perceptions of distance education for head and neck anatomy and the 3D visualization tool. Among the education methods compared, they generally preferred blended learning (n = 47, 39.2%). There was a significant preference for the distance learning method of asynchronous classes (n = 86, 94.5%). Analysis of academic achievements according to whether or not distance education was conducted revealed a significantly higher score in the face-to-face class group (P < 0.05). A blended learning method can be effective in increasing learner satisfaction and improving academic achievement in gross anatomy classes on dental hygiene. It is suggested that theoretical material should be learned through asynchronous content and knowledge expanded through small-group activities during face-to-face learning. This will help establish a standard model for teaching of gross anatomy in dental hygiene in the postpandemic era.
Objective
Periodontitis and osteoarthritis are major public health concerns that result in decreased quality of life among middle‐aged and older adults. We sought to examine whether the severity of ...periodontitis is related to osteoarthritis according to the presence of type 2 diabetes mellitus.
Methods
This study included 3,527 participants age ≥50 years from the Korean National Health and Nutrition Examination Survey. Periodontitis was assessed using the Community Periodontal Index; severe periodontitis was defined as periodontal tissue forming deep periodontal pockets ≥6‐mm depth. Osteoarthritis was defined as Kellgren/Lawrence grade ≥2 on radiographic images of the knee or hip area with joint pain. The odds ratios (ORs) and 95% confidence intervals (95% CIs) for osteoarthritis according to the severity of periodontitis, stratified by type 2 diabetes mellitus, were calculated using multiple logistic regression analyses.
Results
Participants with type 2 diabetes mellitus were more likely to have osteoarthritis as the severity of periodontitis increased (nonsevere periodontitis OR 1.23 95% CI 0.67–2.32; severe periodontitis OR 3.01 95% CI 1.51–5.84) after adjusting for age, sex, body mass index, smoking status, alcohol consumption, regular exercise, education level, household income, hypertension, and frequent tooth‐brushing. However, this positive association was not found in individuals without type 2 diabetes mellitus after adjusting for the same covariables.
Conclusion
Severe periodontitis was positively and significantly associated with osteoarthritis in middle‐aged and older individuals with type 2 diabetes mellitus. Our findings suggest that the oral inflammation manifesting in periodontitis may be at least partly involved in the pathogenesis of osteoarthritis, particularly in patients with type 2 diabetes mellitus.
Diabetes mellitus (DM) characterized by hyperglycemia leads to a variety of complications, including cognitive impairment or memory loss. The hippocampus is a key brain area for learning and memory ...and is one of the regions that is most sensitive to diabetes. However, the pathogenesis of diabetic neuronal lesion is not yet completely understood. We focused on the association of microglia activation and brain lesions in diabetes. In this study, we investigated whether and how signal transducer and activator of transcription 3 (STAT3) activation in microglia affects neuronal lesions in diabetic brains. Using a streptozotocin‐induced type 1 DM model, we showed enhanced hippocampal neuronal apoptosis that was associated with increased STAT3 activation. We found that hyperglycemia increased the expression of inflammatory cytokines such as interferon‐γ (IFN‐γ) and interleukin‐6, in the diabetic hippocampus. In particular, IFN‐γ induced autocrine activation of microglia, and STAT3 activation is important for this process. We also demonstrated that STAT3 activation in microglia increased tumor necrosis factor‐α (TNF‐α) expression; subsequently, TNF‐α increased neuronal apoptosis by increasing reactive oxygen species (ROS) levels in the neuronal cells. We also took advantage of mice lacking STAT3 in microglia and demonstrated that depletion of microglial STAT3 reduced neuronal apoptosis in the diabetic hippocampus. Taken together, these results suggest that STAT3 activation in microglia plays an important role in hyperglycemia‐induced neuronal apoptosis in the diabetic hippocampus and provide a potential therapeutic benefit of STAT3 inhibition in microglia for preventing diabetic neuronal lesions.
We demonstrated that signal transducer and activator of transcription 3 (STAT3) activation in microglia exacerbates neuronal apoptosis of the diabetic hippocampus and that increased tumor necrosis factor‐α (TNF‐α) through STAT3 activation causes neuronal apoptosis. We also took the advantage of mice lacking STAT3 in microglia and demonstrated that depletion of microglial STAT3 reduced neuronal apoptosis in the diabetic hippocampus. There results suggest that STAT3 activation in microglia plays an important role in hyperglycemia‐induced neuronal apoptosis in the diabetic hippocampus and provide a potential therapeutic benefit of STAT3 inhibition in microglia for preventing diabetic neuronal lesions.
Fibroblastic reticular cells (FRCs) are immunologically specialized myofibroblasts of lymphoid organ, and FRC maturation is essential for structural and functional properties of lymph nodes (LNs). ...Here we show that YAP and TAZ (YAP/TAZ), the final effectors of Hippo signaling, regulate FRC commitment and maturation. Selective depletion of YAP/TAZ in FRCs impairs FRC growth and differentiation and compromises the structural organization of LNs, whereas hyperactivation of YAP/TAZ enhances myofibroblastic characteristics of FRCs and aggravates LN fibrosis. Mechanistically, the interaction between YAP/TAZ and p52 promotes chemokine expression that is required for commitment of FRC lineage prior to lymphotoxin-β receptor (LTβR) engagement, whereas LTβR activation suppresses YAP/TAZ activity for FRC maturation. Our findings thus present YAP/TAZ as critical regulators of commitment and maturation of FRCs, and hold promise for better understanding of FRC-mediated pathophysiologic processes.
The Hippo pathway regulates the self-renewal and differentiation of various adult stem cells, but its role in cell fate determination and differentiation during liver development remains unclear. ...Here we report that the Hippo pathway controls liver cell lineage specification and proliferation separately from Notch signalling, using mice and primary hepatoblasts with liver-specific knockout of Lats1 and Lats2 kinase, the direct upstream regulators of YAP and TAZ. During and after liver development, the activation of YAP/TAZ induced by loss of Lats1/2 forces hepatoblasts or hepatocytes to commit to the biliary epithelial cell (BEC) lineage. It increases BEC and fibroblast proliferation by up-regulating TGFβ signalling, but suppresses hepatoblast to hepatocyte differentiation by repressing Hnf4α expression. Notably, oncogenic YAP/TAZ activation in hepatocytes induces massive p53-dependent cell senescence/death. Together, our results reveal that YAP/TAZ activity levels govern liver cell differentiation and proliferation in a context-dependent manner.
Chinese cabbage (
L.) leaves are purple in color due to anthocyanin accumulation and have nutritional and aesthetic value, as well as antioxidant properties. Here, we identified the R3 MYB ...transcription factor BrMYBL2.1 as a key negative regulator of anthocyanin biosynthesis. A Chinese cabbage cultivar with green leaves harbored a functional BrMYBL2.1 protein, designated BrMYBL2.1-G, with transcriptional repressor activity of anthocyanin biosynthetic genes. By contrast, BrMYBL2.1 from a Chinese cabbage cultivar with purple leaves carried a poly(A) insertion in the third exon of the gene, resulting in the insertion of multiple lysine residues in the predicted protein, designated BrMYBL2.1-P. Although both BrMYBL2.1 variants localized to the nucleus, only BrMYBL2.1-G interacted with its cognate partner BrTT8. Transient infiltration assays in tobacco leaves revealed that BrMYBL2.1-G, but not BrMYBL2.1-P, actively represses pigment accumulation by inhibiting the transcription of anthocyanin biosynthetic genes. Transient promoter activation assay in Arabidopsis protoplasts verified that BrMYBL2.1-G, but not BrMYBL2.1-P, can repress transcriptional activation of
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, which was activated by co-expression with BrPAP1 and BrTT8. We determined that BrMYBL2.1-P may be more prone to degradation than BrMYBL2.1-G via ubiquitination. Taken together, these results demonstrate that BrMYBL2.1-G blocks the activity of the MBW complex and thus represses anthocyanin biosynthesis, whereas the variant BrMYBL2.1-P from purple Chinese cabbage cannot, thus leading to higher anthocyanin accumulation.
The present study was conducted to investigate growth performance, carcass characteristics, short-chain fatty acids, fatty acid composition in abdominal fat, and serum parameters in broiler chickens ...fed diets containing corn oil, coconut oil, or black soldier fly larvae (BSFL) oil at the level of 50 g per kg of diet during the 30-day-feeding period. A total 450 one-day-old male broiler chicks (Ross 308) were randomly allocated to one of 3 dietary groups. Each treatment had 10 replicates with 15 chicks per replicate. Feed conversion ratio was decreased in the coconut and BSFL oil group compared with the corn oil group. Dietary BSFL oil increased ileal weight-to-length ratio at day 30 after hatch. Dietary BSFL oil increased significantly ileal branched-chain fatty acid (P < 0.05) and moderately total short-chain fatty acid in 15-day-old broilers (P = 0.074). At day 30, ileal propionate was highest in the coconut oil group but cecal propionate was highest (P < 0.05) in the BSFL oil group. Fatty acid composition of abdominal fat was affected by dietary fat sources. Especially, chickens fed diets containing coconut oil or BSFL oil had higher contents (P < 0.05) of saturated fatty acid being dominant in lauric and myristic acids compared with those fed on corn oil. On the other hand, the reverse trend was noted (P < 0.05) as to polyunsaturated fatty acids being dominant in corn oil compared with coconut oil and BSFL oil. Coconut oil vs. corn oil significantly increased total and high-density lipoprotein cholesterol. Finally, BSFL oil vs. corn oil significantly increased total antioxidant capacity in chickens. It is concluded that dietary BSFL oil improves feed conversion ratio and increases the incorporation of medium-chain fatty acids into abdominal fat pad and serum antioxidant capacity in broiler chickens.
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