ELMO1 Deficiency Reduces Neutrophil Chemotaxis in Murine Peritonitis.

Peritoneal inflammation remains a major cause of treatment failure in patients with kidney failure who receive peritoneal dialysis. Peritoneal inflammation is characterized by an increase in neutrophil infiltration. However, the molecular mechanisms that control neutrophil recruitment in peritonitis are not fully understood. ELMO and DOCK proteins form complexes which function as guanine nucleotide exchange factors to activate the small GTPase Rac to regulate F-actin dynamics during chemotaxis. In the current study, we found that deletion of the Elmo1 gene causes defects in chemotaxis and the adhesion of neutrophils. ELMO1 plays a role in the fMLP-induced activation of Rac1 in parallel with the PI3K and mTORC2 signaling pathways. Importantly, we also reveal that peritoneal inflammation is alleviated in Elmo1 knockout mice in the mouse model of thioglycollate-induced peritonitis. Our results suggest that ELMO1 functions as an evolutionarily conserved regulator for the activation of Rac to control the chemotaxis of neutrophils both in vitro and in vivo. Our results suggest that the targeted inhibition of ELMO1 may pave the way for the design of novel anti-inflammatory therapies for peritonitis.

Rutaecarpine Promotes Adipose Thermogenesis and Protects against HFD-Induced Obesity via AMPK/PGC-1α Pathway.

Pharmacological activation of adaptive thermogenesis to increase energy expenditure is considered to be a novel strategy for obesity. Peroxisome-proliferator-activated receptor γ co-activator-1α (PGC-1α), which serves as an inducible co-activator in energy expenditure, is highly expressed in brown adipose tissues (BAT). In this study, we found a PGC-1α transcriptional activator, natural compound rutaecarpine (Rut), which promoted brown adipocytes mitochondrial biogenesis and thermogenesis in vitro. Chronic Rut treatment reduced the body weight gain and mitigated insulin sensitivity through brown and beige adipocyte thermogenesis. Mechanistic study showed that Rut activated the energy metabolic pathway AMP-activated protein kinase (AMPK)/PGC-1α axis, and deficiency of AMPK abolished the beneficial metabolic phenotype of the Rut treatment in vitro and in vivo. In summary, a PGC-1α transcriptional activator Rut was found to activate brown and beige adipose thermogenesis to resist diet-induced obesity through AMPK pathway. Our findings serve as a further understanding of the natural compound in adipose tissue and provides a possible strategy to combat obesity and related metabolic disorders.

Children and Adolescents' Psychological Well-Being Became Worse in Heavily Hit Chinese Provinces during the COVID-19 Epidemic.

In light of the novel coronavirus's (COVID-19's) threat to public health worldwide, we sought to elucidate COVID-19's impacts on the mental health of children and adolescents in China. Through online self-report questionnaires, we aimed to discover the psychological effects of the pandemic and its associated risk factors for developing mental health symptoms in young people. We disseminated a mental health survey through online social media, WeChat, and QQ in the five Chinese provinces with the most confirmed cases of COVID-19 during the late stage of the country-wide lockdown. We used a self-made questionnaire that queried children and adolescents aged 6 to 18 on demographic information, psychological status, and other lifestyle and COVID-related variables. A total of 17,740 children and adolescents with valid survey data participated in the study. 10,022 (56.5%), 11,611 (65.5%), 10,697 (60.3%), 6868 (38.7%), and 6225 (35.1%) participants presented, respectively, more depressive, anxious, compulsive, inattentive, and sleep-related problems compared to before the outbreak of COVID-19. High school students reported a greater change in depression and anxiety than did middle school and primary school students. Despite the fact that very few children (0.1%) or their family members (0.1%) contracted the virus in this study, the psychological impact of the pandemic was clearly profound. Fathers' anxiety appeared to have the strongest influence on a children's psychological symptoms, explaining about 33% of variation in the child's overall symptoms. Other factors only explained less than 2% of the variance in symptoms once parents' anxiety was accounted for. The spread of COVID-19 significantly influenced the psychological state of children and adolescents in participants' view. It is clear that children and adolescents, particularly older adolescents, need mental health support during the pandemic. The risk factors we uncovered suggest that reducing fathers' anxiety is particularly critical to addressing young people's mental health disorders in this time.

1,25-Dihydroxyvitamin D deficiency induces sarcopenia by inducing skeletal muscle cell senescence.

To determine if 1,25(OH)2D deficiency can induce age-related sarcopenia, the skeletal muscular phenotype of male wild-type (WT) and Cyp27b1 knockout (KO) mice were compared at 3 and 6 months of age. We found that muscle mass, grip strength and muscle fiber size were significantly decreased in aging Cyp27b1 KO male mice. The expression levels of genes related to mitochondrial metabolic activity, and antioxidant enzymes including SOD1, catalase, Nqo1 and Gcs were significantly down-regulated in skeletal muscle tissue of Cyp27b1 KO male mice; in contrast, the percentage of p16+ and p21+ myofibers, and the expression of p16, p19, p21, p53, TNFα, IL6 and MMP3 at mRNA and/or protein levels were significantly increased. We then injected tibialis anterior muscle of WT and Cyp27b1+/- male mice with BaCl2, and analyzed the regenerative ability of skeletal muscle cells 7 days later. The results revealed that the numbers of newly formed regenerating central nucleated fibers (CNF), the percentage of BrdU+ cells and the expression of MyoD, MyHC and Myf5 at mRNA levels were significantly down-regulated in the injured skeletal muscle tissue of Cyp27b1+/- mice. In summary, our studies indicate that 1,25(OH)2D deficiency can result in the development of age-related sarcopenia by inducing oxidative stress, skeletal muscular cell senescence and SASP, and by inhibiting skeletal muscle regeneration. Cyp27b1 KO mice can therefore be used as an animal model of age-related sarcopenia in order to investigate the pathogenesis of age-related sarcopenia and potentially to test intervention measures for treatment of sarcopenia.

ELMO1 Regulates RANKL-Stimulated Differentiation and Bone Resorption of Osteoclasts.

Bone homeostasis is a metabolic balance between the new bone formation by osteoblasts and old bone resorption by osteoclasts. Excessive osteoclastic bone resorption results in low bone mass, which is the major cause of bone diseases such as rheumatoid arthritis. Small GTPases Rac1 is a key regulator of osteoclast differentiation, but its exact mechanism is not fully understood. ELMO and DOCK proteins form complexes that function as guanine nucleotide exchange factors for Rac activation. Here, we report that ELMO1 plays an important role in differentiation and bone resorption of osteoclasts. Osteoclast precursors derived from bone marrow monocytes (BMMs) of Elmo1-/- mice display defective adhesion and migration during differentiation. The cells also have a reduced activation of Rac1, p38, JNK, and AKT in response to RANKL stimulation. Importantly, we show that bone erosion is alleviated in Elmo1-/- mice in a rheumatoid arthritis mouse model. Taken together, our results suggest that ELMO1, as a regulator of Rac1, regulates osteoclast differentiation and bone resorption both in vitro and in vivo.

A resident stromal cell population actively restrains innate immune response in the propagation phase of colitis pathogenesis in mice.

Inflammatory bowel disease (IBD) affects 0.3% of the global population, yet the etiology remains poorly understood. Anti-inflammation therapy has shown great success, but only 60% of patients with IBD benefit from it, indicating that new targets are needed. Here, we report the discovery of an intrinsic counter regulatory mechanism in colitis pathogenesis that may be targeted for IBD treatment. In response to microbial invasion, resident Vimentin+ stromal cells, connective tissue cells genetically marked by Twist2, are activated during the propagation phase of the disease, but not during initiation and resolution phases, and become a primary source of prostaglandin E2 (PGE2). PGE2 induction requires a nuclear factor κB-independent, TLR4-p38MAPK-Cox2 pathway activation. Ablation of each of the pathway genes, but not Rela or Tgfb1, in Twist2 cells enhanced M1 macrophage polarization and granulocyte/T helper 1 (TH1)/TH17 infiltration and aggravated colitis development. PGE2 administration ameliorated colitis in mouse models with defective PGE2 production but not in animals with normal PGE2 induction. Analysis of clinical samples and public domain data revealed increased expression of Cox2, the rate-limiting enzyme of PGE2 biosynthesis, in inflamed tissues, and especially in colon Vimentin+Twist2+ stromal cells, in about 60% of patients with active Crohn's disease or ulcerative colitis. Moreover, Cox2 protein expression was negatively correlated with disease severity, suggesting an involvement of stromal cells in IBD pathogenesis. Thus, the study uncovers an active immune pathway in colitic inflammation that may be targeted to treat patients with IBD with defects in PGE2 production.

Elevated HB-EGF expression in neural stem cells causes middle age obesity by suppressing Hypocretin/Orexin expression.

Obesity is common in the middle aged population and it increases the risks of diabetes, cardiovascular diseases, certain cancers, and dementia. Yet, its etiology remains incompletely understood. Here, we show that ectopic expression of HB-EGF, an important regulator of neurogenesis, in Nestin+ neuroepithelial progenitors with the Cre-LoxP system leads to development of spontaneous middle age obesity in male mice accompanied by hyperglycemia and insulin resistance. The Nestin-HB-EGF mice show decreases in food uptake, energy expenditure, and physical activity, suggesting that reduced energy expenditure underlies the pathogenesis of this obesity model. However, HB-EGF expression in appetite-controlling POMC or AgRP neurons or adipocytes fails to induce obesity. Mechanistically, HB-EGF suppresses expression of Hypocretin/Orexin, an orexigenic neuropeptide hormone, in the hypothalamus of middle aged Nestin-HB-EGF mice. Hypothalamus Orexin administration alleviates the obese and hyperglycemic phenotypes in Nestin-HB-EGF mice. This study uncovers an important role for HB-EGF in regulating Orexin expression and energy expenditure and establishes a midlife obesity model whose pathogenesis involves age-dependent changes in hypothalamus neurons.

1,25-Dihydroxyvitamin D insufficiency accelerates age-related bone loss by increasing oxidative stress and cell senescence.

We investigated the role of insufficiency of the active form of vitamin D, 1,25-dihydroxyvitamin D [1,25(OH)2D] in age-related bone loss. We employed mice with heterozygous deletion of Cyp27b1, the gene encoding the enzyme that synthesizes 1,25(OH)2D, as a model for 1,25(OH)2D insufficiency and compared the phenotype of lumber vertebrae from 3-, 9- and 18-month-old Cyp27b1+/- mice and their wild-type littermates. We found that in wild-type mice, bone mineral density, bone volume, and Cyp27b1 protein expression levels decreased progressively with age, accompanied by declining osteoblastic bone formation and increasing osteoclastic bone resorption, however these age-related skeletal alterations were more severe in Cyp27b1+/- mice which had significantly lower serum 1,25(OH)2D levels. We then assessed the effect of 1,25(OH)2D haploinsufficiency on oxidative stress and DNA damage, cell senescence and senescence-associated secretory phenotype (SASP) in 9-month-old wild-type and Cyp27b1+/- mice. Our results demonstrated that, in Cyp27b1+/- mice compared with their wild-type littermates, the parameters of oxidative stress and DNA damage were significantly increased, whereas the expression levels of antioxidant enzymes were significantly down-regulated; the percentage of senescent osteocytes and bone marrow mesenchymal stem cells, and the expression levels of SASP molecules and p16, p19 and p53 proteins were all significantly increased in bone tissues. Taken together, the results of this study indicate that 1,25(OH)2D insufficiency accelerates age-related bone loss by increasing oxidative stress and DNA damage, inducing bone cell senescence and SASP, and subsequently inhibiting osteoblastic bone formation while stimulating osteoclastic bone resorption.

RelA promotes proliferation but inhibits osteogenic and chondrogenic differentiation of mesenchymal stem cells.

NF-κB is known to be implicated in skeletal development and related diseases. Previous studies have shown that RelA, a key subunit of NF-κB, is involved in osteoblast and chondrocyte survival and differentiation. Yet, the physiological roles of RelA in mesenchymal stem cells (MSCs), which give rise to both chondrocytes and osteoblasts, are still poorly understood. Here, we generated Prrx1-Cre;RelAf/f mice to delete RelA in Prrx1+ bone marrow MSCs and found that RelA deletion led to decreased MSC proliferation and altered differentiation, with increased osteogenic and chondrogenic differentiation but decreased adipogenic differentiation. Bone size and mass were not significantly changed in the mutant mice, although they developed moderate osteoarthritis-like phenotypes. Thus, our studies reveal important but discordant functions of RelA in MSC proliferation and differentiation, and provide an explanation why MSC-specific RelA knockout mice only develop minor skeletal phenotypes.

Bmi1 Overexpression in Mesenchymal Stem Cells Exerts Antiaging and Antiosteoporosis Effects by Inactivating p16/p19 Signaling and Inhibiting Oxidative Stress.

We previously demonstrated that Bmi1 deficiency leads to osteoporosis phenotype by inhibiting the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (MSCs), but it is unclear whether overexpression of Bmi1 in MSCs stimulates skeletal development and rescues Bmi1 deficiency-induced osteoporosis. To answer this question, we constructed transgenic mice (Bmi1Tg ) that overexpressed Bmi1 driven by the Prx1 gene and analyzed their skeletal phenotype differences with that of wild-type littermates. We then hybridized Bmi1Tg to Bmi1-/- mice to generate Bmi1-/- mice overexpressing Bmi1 in MSCs and compared their skeletal phenotypes with those of Bmi1-/- and wild-type mice using imaging, histopathological, immunohistochemical, histomorphometric, cellular, and molecular methods. Bmi1Tg mice exhibited enhanced bone growth and osteoblast formation, including the augmentation of bone size, cortical and trabecular volume, number of osteoblasts, alkaline phosphatase (ALP)-positive and type I collagen-positive areas, number of total colony forming unit fibroblasts (CFU-f) and ALP+ CFU-f, and osteogenic gene expression levels. Consistently, MSC overexpressing Bmi1 in the Bmi1-/- background not only largely reversed Bmi1 systemic deficiency-induced skeletal growth retardation and osteoporosis, but also partially reversed Bmi1 deficiency-induced systemic growth retardation and premature aging. To further explore the mechanism of action of MSCs overexpressing Bmi1 in antiosteoporosis and antiaging, we examined changes in oxidative stress and expression levels of p16 and p19. Our results showed that overexpression of Bmi1 in MSCs inhibited oxidative stress and downregulated p16 and p19. Taken together, the results of this study indicate that overexpression of Bmi1 in MSCs exerts antiaging and antiosteoporosis effects by inactivating p16/p19 signaling and inhibiting oxidative stress. Stem Cells 2019;37:1200-1211.

[Clinical efficacy of the glass ionomer cement used as pit and fissure sealant with and without acid etching in primary teeth].

OBJECTIVE: This work aimed to compare the effect of retention and preventive caries of the pit and fissure sealant on primary teeth by using glass ionomer cements (GIC) with or without acid etching technique. METHODS: In this clinical trail, 100 children aged 3-4 years old with a split-mouth design were equally divided into two groups (the left second upper and lower mandibular primary molars were present in group A, and the right second upper and lower mandibular primary molars were present in group B; each group had 200 molars). All participants were placed in pit and fissure sealant with Ketac® Molar Easymix and seated with atraumatic restorative treatmen press-finger technique in the two groups. Group A was subjected to acid etching (40 s, 35% H3PO4), while group B were not subjected to acid etching. GIC preservation rate, caries rate, and decayed teeth (dt) index were observed after 12 months. RESULTS: After a 12-month follow-up period, the completely lost, partially losing, and losing rates of GIC in 86 children (172 second primary molars) were 83.14%, 9.88%, 6.98% in group A and 62.79%, 20.35%, and 16.86% in group B, respectively. The differences between the two groups were insignificant (P<0.05). The caries rates of groups A and B were 8.14% and 16.86%, and their dt indices were 0.08±0.31 and 1.17±0.46, respectively, thereby indicating significant difference between the two groups (P<0.05). CONCLUSIONS: Using acid etching technology, the retention rate of the pit and fissure sealant increased, while its losing rate decreased. The retention effect of the GIC was improved, and the dental caries prevention effect was enhanced. Sealant processing was a self-curing procedure that sets without the external energy. Hence, this procedure is suitable for the preventive caries of primary teeth in children.

A randomized, controlled clinical trial of one-step self-etching adhesive systems in non-carious cervical lesions.

PURPOSE: To evaluate the clinical effectiveness of two different one-step self-etching adhesives. METHODS: Two single-step self-etching adhesive systems, Clearfil Tri-S Bond and G-Bond, were evaluated. As a control, a two-step self-etching adhesive system, Clearfil SE Bond, was used. The teeth to be restored were randomly assigned. The resin composite used to restore the teeth was Clearfil AP-X. The three adhesive systems were evaluated by Modified USPHS at baseline, 3 months, 6 months, and 12 months. The evaluation consisted of retention rate, color match, marginal discoloration (interfacial staining), marginal adaptation (integrity), wear, post-operative sensitivity, caries recurrence, and other failures. Changes over time and across groups were evaluated statistically using generalized estimating equations. RESULTS: During the 12-month study period, no statistical differences were observed among the three groups (P > 0.05) in retention rate, color match, marginal discoloration (interfacial staining), marginal adaptation (integrity). No wear, post-operative sensitivity, caries recurrence, or other failures were detected in any groups. The two one-step self-etching adhesives tested showed good clinical performance at the end of 12 months.