The FASEB Journal最新文献

Obesity plays a crucial role in the development and progression of type 2 diabetes mellitus (T2DM) by causing excessive release of free fatty acid from adipose tissue, which in turn leads to systemic infiltration of macrophages. In individuals with T2DM, the infiltration of macrophages into pancreatic islets results in islet inflammation that impairs beta cell function, as evidenced by increased apoptosis and decreased glucose-stimulated insulin secretion. The present study aimed to investigate the effects of non-lethal sonodynamic therapy (NL-SDT) on bone marrow-derived macrophages (BMDMs) exposed to high glucose and palmitic acid (HG/PA). These findings indicate that NL-SDT facilitates the expression of DRP1 through the transient production of mitochondrial ROS, which subsequently promotes mitophagy. This mitophagy was shown to limit the activation of the NLRP3 inflammasome and the secretion of IL-1β in BMDMs exposed to HG/PA. In co-culture experiments, beta cells exhibited significant dysfunction when interacting with HG/PA-treated BMDMs. However, this dysfunction was markedly alleviated when the BMDMs had undergone NL-SDT treatment. Moreover, NL-SDT was found to lower blood glucose levels and elevate serum insulin concentrations in db/db mice. Furthermore, NL-SDT effectively reduced the infiltration of F4/80-positive macrophages and the expression of CASP1 within islets. These findings provide fundamental insights into the mechanisms through which NL-SDT may serve as a promising approach for the treatment of T2DM.

Mitogen-inducible gene 6 (Mig6) is a cellular inhibitor of epidermal growth factor receptor (EGFR) that binds directly to the EGFR kinase domain and interferes with signaling. Reduced Mig6 expression is correlated with increased EGFR activity in multiple cancer models. Here, we investigated whether disease-associated point mutations could reduce the inhibitory potency of Mig6. We show that several cancer-associated mutations, and a mutation derived from Alzheimer's Disease patients, diminish the ability of Mig6 to bind and inhibit EGFR in vitro. In mammalian cells, the mutations decreased the Mig6-induced suppression of basal and EGF-stimulated autophosphorylation, MAP kinase phosphorylation, and cell migration. To probe the mechanisms by which the mutations could lead to reduced Mig6 inhibition, we constructed atomic-level computational models of Mig6 complexed with the EGFR catalytic domain, and performed molecular dynamics simulations for wild-type and mutant complexes.

One exercise session can increase subsequent insulin-stimulated glucose uptake (ISGU) by skeletal muscle. Postexercise refeeding induces reversal of postexercise (PEX)-enhanced ISGU concomitant with attaining high muscle glycogen in rats. To test the relationship between high glycogen and reversal of PEX-ISGU, we injected one epitrochlearis muscle from each rat with adeno-associated virus (AAV) small hairpin RNA (shRNA) that targets glycogen synthase 1 (GS1) and injected contralateral muscles with AAV-shRNA-Scrambled (Scr). Muscles from PEX and sedentary rats were collected at 3-hour PEX (3hPEX) or 6-hour PEX (6hPEX). Rats were either not refed or refed rat-chow during the recovery period. Isolated muscles were incubated with [³H]-3-O-methylglucose, with or without insulin. The results revealed: (1) GS1 abundance was substantially lower for AAV-shRNA-GS1-treated versus AAV-shRNA-Scr-treated muscles; (2) reduced GS1 abundance in refed-rats induced much lower glycogen in AAV-shRNA-GS1-treated versus AAV-shRNA-Scr-treated muscles at 3hPEX or 6hPEX; (3) PEX-ISGU was elevated in not refed-rats at either 3hPEX or 6hPEX versus sedentary controls, regardless of GS1 abundance; (4) PEX-ISGU was not reversed by 3 h of refeeding, regardless of GS1 abundance; (5) despite substantially lower glycogen in AAV-shRNA-GS1-treated versus AAV-shRNA-Scr-treated muscles, elevated PEX-ISGU was eliminated at 6hPEX in both of the paired muscles of refed-rats; and (6) 3hPEX versus sedentary non-refed rats had greater AMP-activated protein kinase-γ3 activity in both paired muscles, but this exercise effect was eliminated in both paired muscles by 3 h of refeeding. In conclusion, the results provided compelling evidence that the reversal of exercise-enhanced ISGU by refeeding was not attributable to the accumulation of high muscle glycogen concentration.

Breast cancer patients have high serum reactive oxygen species (ROS) levels, which exert toxicity on the ovary. However, it is still unclear whether tumor-derived ROS play a role in endometrial development and function in breast cancer. Breast cancer patients and healthy controls were recruited and endometrial thickness was measured by transvaginal ultrasound (TVUS). Xenograft tumors of the breast cancer cell line MDA–MB–231 in a female BALB/c nude mice model were established, and the therapeutic mechanism of vitamin C (VC) was investigated on uterine pathology in vivo and the contribution of co-culture of breast cancer cell and endometrial epithelial cell on this process was examined in vitro. Median thickness in endometria was lower in breast cancer patients and tumor-bearing mice compared to controls. A gene signature of uteri in tumor-bearing mice demonstrated differential expression of genes (DEGs) regulating extracellular matrix (ECM) and epithelial–mesenchymal transition (EMT), and activation of TGF-β and MAPK signaling pathways. In addition, ROS, EMT- and ECM-related protein levels were enhanced in uteri in tumor-bearing mice, as well as in Ishikawa cells which were co-cultured with MDA-MB-231 cells compared to controls. Supplementation with VC reduced endometrial damage, inhibited the EMT process and collagen deposition, and maintained better histologic architecture of uteri in tumor-bearing mice via inactivation of the TGF-β1/p38MAPK pathway. In women with breast cancer oxidative stress in the endometrium results in a fibrotic response as a consequence of EMT. VC could alleviate endometrial fibrosis via TGF-β1/p38MAPK pathway and provide new predictive and therapeutic targets for fertility preservation in younger breast cancer patients.

Preterm labor is the leading cause of neonatal death and major morbidity but remains a poorly understood process with no effective tocolytic therapies. Recent work has identified the transient receptor potential vanilloid 4 (TRPV4) channel, a membrane calcium channel upregulated in uterine smooth muscle through gestation, as integral in the transition from quiescence to contraction in the gravid uterus. The present study builds upon these findings and investigates regulation of the TRPV4 channel during pregnancy in the murine and human uterus by micro-RNA 203 (miR-203). We find a progressive decrease in miR-203 expression during gestation, accompanied by a reciprocal increase in TRPV4 mRNA and protein expression. In human uterine smooth muscle cells (UtSMC), miR-203 overexpression reduces, and si-RNA-mediated silencing increases, TRPV4 expression. Studies using murine UtSMC demonstrate that miR-203 expression modulates TRPV4-mediated cytosolic calcium entry and contractility. Consistent with these findings, the response to pharmacologic TRVP4 agonists is increased in myometrial tissue from miRNA203 ^−/− mice compared to control mice. Moreover, we demonstrate that miR-203 binds specifically on the promoter region of TRPV4 to decrease expression. In murine inflammatory models of preterm labor, miR-203 overexpression prolongs pregnancy. Estradiol (E2) decreases miR-203 and increases TRPV4 expression, providing a potential physiologic link for the unique reciprocal relationship in UtSMC. Taken together, these findings provide evidence that miR-203 modulates uterine contractility during pregnancy via negative regulation of TRPV4. These findings support the hypothesis that targeting miR-203 holds the promise of an entirely novel approach to prevent prematurity and treat preterm labor.

Resistance exercise upregulates and downregulates the expression of a wide range of genes in skeletal muscle. However, detailed analysis of mRNA dynamics such as response rates and temporal patterns of the transcriptome after resistance exercise has not been performed. We aimed to clarify the dynamics of time-series transcriptomics after resistance exercise. We used electrical stimulation-induced muscle contraction as a resistance exercise model (5 sets × 10 times of 3 s of 100-Hz electrical stimulation) on the tibialis anterior muscle of rats and measured the transcriptome in the muscle before and at 0, 1, 3, 6, and 12 h after muscle contractions by RNA sequencing. We also examined the relationship between the parameters of mRNA dynamics and the increase in protein expression at 12 h after muscle contractions. We found that the function of the upregulated genes differed after muscle contractions depending on their response rate. Genes related to muscle differentiation and response to mechanical stimulus were enriched in the sustainedly upregulated genes. Furthermore, there was a positive correlation between the magnitude of upregulated mRNA expression and the corresponding protein expression level at 12 h after muscle contractions. Although it has been theoretically suggested, this study experimentally demonstrated that the magnitude of the mRNA response after electrical stimulation-induced resistance exercise contributes to skeletal muscle adaptation via increases in protein expression. These findings suggest that mRNA expression dynamics such as response rate, a sustained upregulated expression pattern, and the magnitude of the response contribute to mechanisms underlying adaptation to resistance exercise.

RETRACTION: M. Liu, Y. Yang, C. Gu, Y. Yue, K. K. Wu, J. Wu, and Y. Zhu, “Spike Protein of SARS-CoV Stimulates Cyclooxygenase-2 Expression via Both Calcium-Dependent and Calcium-Independent Protein Kinase C Pathways,” The FASEB Journal 21, no. 7 (2007): 1586–1596, https://doi.org/10.1096/fj.06-6589com.

The above article, published online on 31 January 2007, in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the journal Editor-in-Chief, Loren E. Wold; the Federation of American Societies for Experimental Biology; and Wiley Periodicals LLC. The retraction has been agreed upon following an investigation into concerns raised by a third party which revealed inappropriate image section duplications within the article (Figures 1D, 4B, 5A and B, 6B and C, 7D and 8) and between this (Figure 4B) and another article published previously in a different scientific context. Due to the number and the level of errors identified in the published figures, the editors have lost confidence in the presented data and consider the conclusions substantially compromised. The authors have been informed about the concerns, but did not provide an explanation and due to the time elapsed since publication the original raw data are not available.

Osteopenia is frequently observed in patients with iron overload, especially in those with HFE-dependent hereditary hemochromatosis (HH). Interestingly, not all mouse models of HH show bone loss, suggesting that iron overload alone may not suffice to induce bone loss. In this study, the bone phenotypes of Hjv^−/− and hepatocyte-specific Alk2- and Alk3-deficient mice as additional mouse models of HH were investigated to further clarify, how high iron levels lead to bone loss and which signaling mechanisms are operational. Neither male nor female 12-week-old Hjv^−/− mice had an altered trabecular or cortical bone mass or bone turnover, despite severe iron overload. Male 12-month-old Hjv^−/− mice even presented with a higher femoral trabecular bone volume compared to wildtype mice. Similarly, female mice with hepatocyte-specific Alk2 or Alk3 deficiency did not show an altered bone phenotype at 3, 6, and 12 months of age. Male hepatocyte-specific Alk3-deficient mice also had a normal trabecular bone mass at all ages analyzed, despite showing increased bone resorption and decreased bone formation parameters. Interestingly, hepatocyte-specific Alk2-deficient mice showed reduced femoral trabecular bone at 6 months of age due to suppressed bone formation. Cortical thickness at the femur was reduced in both, 6-month-old male hepatocyte-specific Alk2- and Alk3-deficient mice. Raising hepatocyte-specific Alk2-deficient male mice on an iron-deficient diet rescued the bone phenotype. Taken together, despite iron overload, trabecular bone microarchitecture was not altered in mice deficient of Hjv or Alk3. Only male hepatocyte-specific Alk2-deficient mice showed site-specific lower trabecular and cortical bone mass at the femur, which was dependent on iron. Thus, bone loss does not correlate with the extent of iron overload in these mouse models, but may relate to the amount of iron-loaded macrophages, as precursors of osteoclasts, in the bone marrow.

Topologically associating domains (TADs) are chromatin domains in the eukaryotic genome. TADs often comprise several sub-TADs. The boundaries of TADs and sub-TADs are enriched in CTCF, an architectural protein. Deletion of CTCF-binding motifs at one boundary disrupts the domains, often resulting in a transcriptional decrease in genes inside the domains. However, it is not clear how TAD and sub-TAD affect each other in the domain formation. Unaffected gene transcription was observed in the β-globin locus when one boundary of TAD or sub-TAD was destroyed. Here, we disrupted β-globin TAD and sub-TAD by deleting CTCF motifs at both boundaries in MEL/ch11 cells. Disruption of TAD impaired sub-TAD, but sub-TAD disruption did not affect TAD. Both TAD and sub-TAD disruption compromised the β-globin transcription, accompanied by the loss of enhancer–promoter interactions. However, histone H3 occupancy and H3K27ac were largely maintained across the β-globin locus. Genome-wide analysis showed that putative enhancer–promoter interactions and gene transcription were decreased by the disruption of CTCF-mediated topological domains in neural progenitor cells. Collectively, our results indicate that there is unequal relationship between TAD and sub-TAD formation. TAD is likely not sufficient for gene transcription, and, therefore, sub-TAD appears to be required. TAD-dependently formed sub-TADs are considered to provide chromatin environments for enhancer–promoter interactions enabling gene transcription.

Orthodontically induced root resorption (OIRR) is a common side effect during orthodontic tooth treatment (OTM). The function of osteoprotegerin (OPG) is considered to protect cementum from excessive resorption to maintain root integrity. In this study, we observed that the expression of TGF-β1 and OPG was upregulated under the loading of orthodontic force in periodontal tissues. However, the specific molecular mechanisms of TGF-β1-induced OPG expression in cementoblasts are not fully elucidated. This study aims to investigate the effect of Smads and AP-1 stimulated by TGF-β signaling on the transcription of OPG in cementoblasts. In vitro, we demonstrated that TGF-β/Smad and AP-1 signaling involved in TGF-β1-induced extracellular secretion of OPG in conditioned media (CM) from cementoblasts, which further inhibited osteoclastogenesis. Reporter gene plasmids containing OPG promoter sequences of different lengths (0.5–3 kb) were constructed to investigate the potential binding sites of Smads and AP-1. We identified nine binding sites of Smads and AP-1 concentrated in the 0–0.5 and 2.3–3 kb regions of OPG promoter in cementoblasts. ChlP results showed that Smad2/3/4 and c-Jun were bound more to the OPG promoter under TGF-β1 stimulation. In vivo, localized administration of TGF-β1 in the OTM model increased OPG expression, which resulted in the inhibition of OIRR. In summary, TGF-β1-induced Smads and AP-1 can bind to the OPG promoter to promote the transcription, expression, and secretion of OPG in cementoblasts, which inhibits osteoclast differentiation and protects cementum from excessive resorption.