The double-edged sword role of TGF-ß signaling pathway between intrauterine inflammation and cranial neural crest development.

Intrauterine infection would harm a developing embryo/fetus, thereby increasing the risk of developmental malformation. But, whether or not the infection-induced inflammation affects neural crest development still remains obscure. In this study, we employed meta-analysis to demonstrate the potential correlation between infection-induced inflammation and craniofacial anomalies, which was usually derived from the problems in neural crest cell development. The correlation was further verified by inflammatory cytokine release and the activation of nuclear factor kappa-light-chain enhancer of activated B cells signaling in lipopolysaccharide-treated HH10 chicken embryos. In such an inflammatory condition, AP-2α- and Pax7-labeled pre-migratory and migratory neural crest cells in HH10 chicken embryos were significantly less than the ones in control. The bioinformatics analysis of RNA-seq data demonstrated that the principal differential gene expression occurred in transforming growth factor-beta (TGF-ß) signaling pathway, which was confirmed by the subsequent experimental results of quantitative PCR and immunofluorescent staining. Under this inflammatory circumstance, whole-mount in situ hybridization, immunofluorescence, and quantitative PCR showed the gene expression changes of key EMT-related transcription factors including upregulated Msx1, downregulated Slug, and FoxD3, as well as adhesion molecules and extracellular matrix protein including upregulated Cadherrin6B, E-cadherin, N-cadherin, and Laminin at the dorsal portion of neural tube of HH10 chicken embryos. Meanwhile, the bioinformatics analysis of RNA-seq data also manifested the differential gene expressions relevant to cell proliferation, which was confirmed by proliferating cell nuclear antigen Western blot data and co-immunofluorescence staining of human natural killer-1 and phosphorylated histone H3. In brief, this study revealed for the first time that the double-edged sword role of TGF-ß signaling pathway between intrauterine inflammation (protective role) and cranial neural crest development (harmful role).

Gut-Lung Dysbiosis Accompanied by Diabetes Mellitus Leads to Pulmonary Fibrotic Change through the NF-κB Signaling Pathway.

Growing evidence shows that the lungs are an unavoidable target organ of diabetic complications. However, the pathologic mechanisms of diabetic lung injury are still controversial. This study demonstrated the dysbiosis of the gut and lung microbiome, pulmonary alveolar wall thickening, and fibrotic change in streptozotocin-induced diabetic mice and antibiotic-induced gut dysbiosis mice compared with controls. In both animal models, the NF-κB signaling pathway was activated in the lungs. Enhanced pulmonary alveolar well thickening and fibrotic change appeared in the lungs of transgenic mice expressing a constitutively active NF-κB mutant compared with wild type. When lincomycin hydrochloride-induced gut dysbiosis was ameliorated by fecal microbiota transplant, enhanced inflammatory response in the intestine and pulmonary fibrotic change in the lungs were significantly decreased compared with lincomycin hydrochloride-treated mice. Furthermore, the application of fecal microbiota transplant and baicalin could also redress the microbial dysbiosis of the gut and lungs in streptozotocin-induced diabetic mice. Taken together, these data suggest that multiple as yet undefined factors related to microbial dysbiosis of gut and lungs cause pulmonary fibrogenesis associated with diabetes mellitus through an NF-κB signaling pathway.

Dysbacteriosis-induced LPS elevation disturbs the development of muscle progenitor cells by interfering with retinoic acid signaling.

Whether myogenesis is affected by the maternal gut dysbacteriosis still remains ambiguous. In this study, first we show the elevated level of lipopolysaccharides (LPS) in a gut microbiota dysbiosis mouse model. Second, we demonstrate that the diameter of muscle fibers, limb development, and somitogenesis were inhibited in both the gut microbiota dysbiosis and LPS exposed mice and chicken embryos. These might be due to LPS disturbed the cell survival and key genes which regulate the somitogenesis and myogenesis. RNA sequencing and subsequent validation experiments verified that retinoic acid (RA) signaling perturbation was mainly responsible for the aberrant somite formation and differentiation. Subsequently, we found that LPS-induced reactive oxygen species (ROS generation and antioxidant genes such as Nrf2, AKR1B10) contributed to the above -mentioned interference with RA signaling. These findings highlight that the gut microbiota homeostasis is also involved in regulating the development of muscle progenitor cells during pregnancy.

Dysbacteriosis induces abnormal neurogenesis via LPS in a pathway requiring NF-κB/IL-6.

In this study, we identified elevated levels of LPS and suppressed neurogenesis in a successfully established mouse model of gut microbiota dysbiosis. We mimicked these phenotypes using mouse and chicken embryos exposed to LPS and found that dramatic variation in gene expression was due to changes in the dorsal-ventral patterning of the neural tube. Cell survival and excess ROS were also involved in this process. Antioxidant administration alleviated LPS-activated NF-κB signaling, while directly blocking NF-κB signaling altered the LPS-induced inhibition of neurogenesis. Furthermore, IL-6 was proven to play a vital role in the expression of crucial neurogenesis-related genes and NF-κB. In summary, we found that the suppression of neurogenesis induced by dysbacteriosis-derived LPS was significantly reversed in mice with fecal microbiota transplantation. This study reveals that gut dysbacteriosis-derived LPS impairs embryonic neurogenesis, and that the NF-κB/IL-6 pathway could be one of the main factors triggering the downstream signaling cascade.

Dysbacteriosis-Derived Lipopolysaccharide Causes Embryonic Osteopenia through Retinoic-Acid-Regulated DLX5 Expression.

Growing evidence suggests an adverse impact of gut microbiota dysbiosis on human health. However, it remains unclear whether embryonic osteogenesis is affected by maternal gut dysbacteriosis. In this study, we observed that elevated lipopolysaccharide (LPS) levels led to skeletal developmental retardation in an established mouse model of gut microbiota dysbiosis. Using chick embryos exposed to dysbacteriosis-derived LPS, we found restriction in the development of long bones as demonstrated by Alcian blue and alizarin red staining. Micro-CT and histological analysis exhibited decreased trabecular volume, bone mineral density, and collagen production, as well as suppressed osteoblastic gene expression (Ocn, Runx2, Osx, and Dlx5) in chick embryonic phalanges following LPS treatment. Atomic force microscopy manifested decreased roughness of MC3T3-E1 cells and poorly developed matrix vesicles (MVs) in presence of LPS. The expression of the aforementioned osteoblastic genes was suppressed in MC3T3-E1 cells as well. High-throughput RNA sequencing indicated that retinoic acid (RA) may play an important role in LPS-induced osteopenia. The addition of RA suppressed Dlx5 expression in MC3T3-E1 cells, as was also seen when exposed to LPS. Quantitative PCR, Western blot, and immunofluorescent staining showed that retinoic acid receptor α (RARα) was upregulated by LPS or RA treatment, while the expression of DLX5 was downregulated. CYP1B1 expression was increased by LPS treatment in MC3T3-E1 cells, which might be attributed to the increased inflammatory factors and subsequently activated NF-κB signaling. Eventually, blocking RA signals with AGN193109 successfully restored LPS-inhibited osteoblastic gene expression. Taken together, our data reveals that maternal gut microbiota dysbiosis can interfere with bone ossification, in which Dlx5 expression regulated by RA signaling plays an important role.

Atractylenolide-I Alleviates Hyperglycemia-Induced Heart Developmental Malformations through Direct and Indirect Modulation of the STAT3 Pathway.

BACKGROUND: Gestational diabetes could elevate the risk of congenital heart defects (CHD) in infants, and effective preventive and therapeutic medications are currently lacking. Atractylenolide-I (AT-I) is the active ingredient of Atractylodes Macrocephala Koidz (known as Baizhu in China), which is a traditional pregnancy-supporting Chinese herb. PURPOSE: In this study, we investigated the protective effect of AT-I on the development of CHD in embryos exposed to high glucose (HG). STUDY DESIGN AND METHODS: First, systematic review search results revealed associations between gestational diabetes mellitus (GDM) and cardiovascular malformations. Subsequently, a second systematic review indicated that heart malformations were consistently associated with oxidative stress and cell apoptosis. We assessed the cytotoxic impacts of Atractylenolide compounds (AT-I, AT-II, and AT-III) on H9c2 cells and chick embryos, determining an optimal concentration of AT-I for further investigation. Second, immunofluorescence, western blot, Polymerase Chain Reaction (PCR), and flow cytometry were utilized to delve into the mechanisms through which AT-I mitigates oxidative stress and apoptosis in cardiac cells. Molecular docking was employed to investigate whether AT-I exerts cardioprotective effects via the STAT3 pathway. Then, we developed a streptozotocin-induced diabetes mellitus (PGDM) mouse model to evaluate AT-I's protective efficacy in mammals. Finally, we explored how AT-I protects hyperglycemia-induced abnormal fetal heart development through microbiota analysis and untargeted metabolomics analysis. RESULTS: The study showed the protective effect of AT-I on embryonic development using a chick embryo model which rescued the increase in the reactive oxygen species (ROS) and decrease in cell survival induced by HG. We also provided evidence suggesting that AT-I might directly interact with STAT3, inhibiting its phosphorylation. Further, in the PGDM mouse model, we observed that AT-I not only partially alleviated PGDM-related blood glucose issues and complications but also mitigated hyperglycemia-induced abnormal fetal heart development in pregnant mice. This effect is hypothesized to be mediated through alterations in gut microbiota composition. We proposed that dysregulation in microbiota metabolism could influence the downstream STAT3 signaling pathway via EGFR, consequently impacting cardiac development and formation. CONCLUSIONS: This study marks the first documented instance of AT-I's effectiveness in reducing the risk of early cardiac developmental anomalies in fetuses affected by gestational diabetes. AT-I achieves this by inhibiting the STAT3 pathway activated by ROS during gestational diabetes, significantly reducing the risk of fetal cardiac abnormalities. Notably, AT-I also indirectly safeguards normal fetal cardiac development by influencing the maternal gut microbiota and suppressing the EGFR/STAT3 pathway.

EGFR/MAPK signaling pathway acts as a potential therapeutic target for sulforaphane-rescued heart tube malformation induced by various concentrations of PhIP exposure.

BACKGROUND: 2-Amino-1-methyl-6-phenylimidazo [4,5-b] pyrimidine (PhIP) is a known carcinogen generated mainly from cooking meat and environmental pollutants. It is worth exploring the potential of natural small-molecule drugs to protect against adverse effects on embryonic development. PURPOSE: In this study, we investigated the potential toxicological effects of PhIP on embryonic heart tube formation and the effect of Sulforaphane (SFN) administration on the anti-toxicological effects of PhIP on embryonic cardiogenesis. STUDY DESIGN AND METHODS: First, the chicken embryo model was used to investigate the different phenotypes of embryonic heart tubes induced by various concentrations of PhIP exposure. We also proved that SFN rescues PhIP-induced embryonic heart tube malformation. Second, immunofluorescence, western blot, Polymerase Chain Reaction (PCR) and flow cytometry experiments were employed to explore the mechanisms by which SFN protects cardiac cells from oxidative damage in the presence of PhIP. We used RNA-seq analysis, molecular docking, in situ hybridization, cellular thermal shift assay and solution nuclear magnetic resonance spectroscopy to explore whether SFN protects cardiogenesis through the EGFR/MAPK signaling pathway. RESULTS: The study showed that PhIP might dose-dependently interfere with the C-looping heart tube (mild) or the fusion of a pair of bilateral endocardial tubes (severe) in chick embryos, while SFN administration prevented cardiac cells from oxidative damage in the presence of high-level PhIP. Furthermore, we found that excessive reactive oxygen species (ROS) production and subsequent apoptosis were not the principal mechanisms by which low-level PhIP induced malformation of heart tubes. This is due to PhIP-disturbed Mitogen-activated protein kinase (MAPK) signaling pathway could be corrected by SFN administration. CONCLUSIONS: This study provided novel insight that PhIP exposure could increase the risk of abnormalities in early cardiogenesis and that SFN could partially rescue various concentrations of PhIP-induced abnormal heart tube formation by targeting EGFR and mediating EGFR/MAPK signaling pathways.

Retinoic Acid Signaling Plays a Crucial Role in Excessive Caffeine Intake-Disturbed Apoptosis and Differentiation of Myogenic Progenitors.

Whether or not the process of somitogenesis and myogenesis is affected by excessive caffeine intake still remains ambiguous. In this study, we first showed that caffeine treatment results in chest wall deformities and simultaneously reduced mRNA expressions of genes involved in myogenesis in the developing chicken embryos. We then used embryo cultures to assess in further detail how caffeine exposure affects the earliest steps of myogenesis, and we demonstrated that the caffeine treatment suppressed somitogenesis of chicken embryos by interfering with the expressions of crucial genes modulating apoptosis, proliferation, and differentiation of myogenic progenitors in differentiating somites. These phenotypes were abrogated by a retinoic acid (RA) antagonist in embryo cultures, even at low caffeine doses in C2C12 cells, implying that excess RA levels are responsible for these phenotypes in cells and possibly in vivo. These findings highlight that excessive caffeine exposure is negatively involved in regulating the development of myogenic progenitors through interfering with RA signaling. The RA somitogenesis/myogenesis pathway might be directly impacted by caffeine signaling rather than reflecting an indirect effect of the toxicity of excess caffeine dosage.

Gestational diabetes mellitus in women increased the risk of neonatal infection via inflammation and autophagy in the placenta.

BACKGROUND: Gestational diabetes mellitus (GDM) produces numerous problems for maternal and fetal outcomes. However, the precise molecular mechanisms of GDM are not clear. METHODS: In our study, we randomly assigned 22 pregnant women with fasting glucose concentrations, 1 hour oral glucose tolerance test (1H-OGTT) and 2 hour oral glucose tolerance test (2H-OGTT), different than 28 normal pregnant women from a sample of 107 pregnant women at the First Affiliated Hospital of Jinan University in China. Lipopolysaccharide (LPS), interleukin 1 alpha (IL-1α), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor alpha (TNF-α) were measured from blood plasma of pregnant women and umbilical arteries using ultraviolet spectrophotometry. Hematoxylin & Eosin (H&E), Periodic acid-Schiff (PAS) or Masson staining were performed to examine whether diabetes mellitus altered the morphology of placenta. Quantitative PCR (Q-PCR), western blotting and immunofluorescent staining were performed to examine whether diabetes mellitus and autophagy altered the gene expressions of the placental tissue. RESULTS: We found that women with GDM exhibited increased placental weight and risk of neonatal infection. The concentrations of IL-6 protein and IL-8 protein in GDM were increased in both maternal and umbilical arterial blood. H&E, Masson and PAS staining results showed an increased number of placental villi and glycogen deposition in patients with GDM, but no placental sclerosis was found. Q-PCR results suggested that the expression levels of HIF-1α and the toll like receptor 4 (TLR4)/ myeloid differential protein-88 (MyD88)/ nuclear factor kappa-B (NF-κB) pathway were increased in the GDM placenta. Through Western Blotting, we found that the expression of NF-kappa-B inhibitor alpha (IKBα) and Nuclear factor-κB p65 (NF-κB p65) in GDM placenta was significantly enhanced. We also showed that the key autophagy-related genes, autophagy-related 7 (ATG7) and microtubule-associated protein 1A/1B-light chain 3 (LC3), were increased in GDM compared with normal pregnant women. CONCLUSIONS: Our results suggest that women with GDM exhibit an increased risk of neonatal infection via inflammation and autophagy in the placenta.

Baicalin rescues hyperglycemia-induced neural tube defects via targeting on retinoic acid signaling.

We, in this study, studied whether or not antioxidant activities of Baicalin could reduce the incidence of neural tube defects (NTDs) in the presence of hyperglycemia. Using early chick embryos, we demonstrated that Baicalin at 6 µM dramatically reduced NTDs rate and impaired neurogenesis in E4.5-day and HH10 chick embryo neural tubes induced by high glucose (HG). Likewise, immunofluorescent staining showed that Baicalin mitigated the HG-induced regression of Pax7 expression in neural tubes of both HH10 and E4.5-day chick embryos. Additionally, PHIS3 immunofluorescent staining in neural tubes of both HH10 and E4.5-day chick embryos manifested that cell proliferation inhibited by HG was significantly reversed by the administration of Baicalin, and similar result could also be observed in neurosphere assay in vitro. c-Caspase3 or γH2AX immunofluorescent staining and quantitative PCR showed that Baicalin administration alleviated HG-induced cell apoptosis and DNA damage. Bioinformatics results indicated that retinoic acid (RA) was likely to be the signaling pathway that Baicalin targeted on, and this was confirmed by whole-mount RALDH2 in situ hybridization and quantitative PCR of HH10 chick embryos in the absence/presence of Baicalin. In addition, blocking RA with an inhibitor abolished Baicalin's protective role in HG-induced NTDs, suppression of neurogenesis and cell proliferation, and induction of apoptosis, which further verified the centrality of RA in the process of Baicalin confronting HG-induced abnormal neurodevelopment.