Both partial inactivation as well as activation of NF-κB signaling lead to hypertension and chronic kidney disease

BACKGROUND

Activation of nuclear factor-kappa B (NF-κB) signalling is key in the pathogenesis of chronic kidney disease (CKD). However, a certain level of NF-κB activity is necessary to enable tissue repair.

METHODS

The relationship between activated and inactivated NF-κB signaling and the pathogenesis of CKD was investigated using mouse models of NF-κB partial inactivation (mutating cysteine at position 59 of the sixth exon on the NF-κB gene into alanine) and activation (mutating cysteine at position 59 of the sixth exon on the NF-κB gene into serine).

RESULTS

The density of CD3, CD8, CD68 positive cells, as well as the expression of interleukin 6, Tumor necrosis factor receptor associated factor 1 and Nef-associated factor 1 in the kidney tissues of NF-κBC59A mice were reduced, whereas an opposing pattern was observed in the NF-κBC59S mice. Blood pressure, kidney fibrosis (analyzed by periodic acid-Schiff, Masson trichrome and Sirius Red staining, as well as α-SMA immunofluorescence), serum creatinine and urinary albumin-to-creatinine ratio are markedly increased in NF-κB-activated and -inactivated mice compared with controls. Transmission electron microscopy indicated that the glomerular basement membrane was thicker in both NF-κBC59A and NF-κBC59S mice compared with wild-type mice.

CONCLUSIONS

Using mice models with partially activated and inactivated NF-κB pathways suggests that there is an apparently U-shaped relationship between blood pressure, kidney function as well as morphology and the activation of the NF-κB pathway. A certain optimal activity of the NF-κB pathway seems to be important to maintain optimal kidney function and morphology.

The antisense lncRNA of TAB2 that prevents oxidative stress to enhance the follicular growth in mammals

LncRNAs are highly implicated in oxidative stress (OS) during the growth of mammalian follicles. TAK1 binding protein 2 gene (TAB2) has been suggested to involve in the normal apoptosis and proliferation of granulosa cells (GCs), the main supporting cells in ovarian follicles. In this study, we found that TAB2 increased the expressions of SOD1, P50, and P65 to suppress the OS, thereby inhibiting the apoptosis and promoting the proliferation in GCs. Notably, DNMTs appeared to mediate the expression of TAB2 without the changes of DNA methylation at TAB2's promoter. We identified an antisense lncRNA of TAB2, discovered that DNA methylation regulated the transcription of TAB2-AS in GCs, and found TAB2-AS medicated the follicular growth of ovaries in vivo. Mechanistically, the hypomethylation of the CpG site (-1759/-1760) activated the transcription of TAB2-AS, and the 1-155 nt and 156-241 nt of TAB2-AS were respectively complementary to 4368-4534 nt and 4215-4300 nt of TAB2's mRNA to increase the expression of TAB2. Moreover, TAB2-AS inhibited the OS and apoptosis of GCs, while promoted the proliferation of GCs to expedite the follicular growth, which was in line with that of TAB2. Collectively, these findings revealed the antisense lncRNA mechanism mediated by DNA methylation, and TAB2-AS might be the target to control OS during follicular growth in mammals.

Inhibition of the NF-κB signaling pathway affects gonadal differentiation and leads to male bias in Paramisgurnus dabryanus

In recent years, sex-controlled breeding has emerged as an effective strategy to enhance the yields of economic animals with different growth characteristics, while increasing the economic benefits of aquaculture. It is known that the NF-κB pathway participates in gonadal differentiation and reproduction. Therefore, we used the large-scale loach as a research model for the present study and selected an effective inhibitor of the NF-κB signaling pathway (QNZ). This, to investigates the impacts of the NF-κB signaling pathway on gonadal differentiation during a critical period of gonad development and after maturation. Simultaneously, the sex ratio bias and the reproductive capacities of adult fish were analyzed. Our results indicated that the inhibition of the NF-κB signaling pathway influenced the expression of genes related to gonad development, regulated the gene expression related to the brain-gonad-liver axis of juvenile loaches, and finally impacted the gonadal differentiation of the large-scale loach and promoted a male-biased sex ratio. Meanwhile, high QNZ concentrations affected the reproductive abilities of adult loaches and inhibited the growth performance of offspring. Thus, our results deepened the exploration of sex control in fish and provided a certain research basis for the sustainable development of the aquaculture industry.

Alpha-2-macroglobulin is involved in the occurrence of early-onset pre-eclampsia via its negative impact on uterine spiral artery remodeling and placental angiogenesis

BACKGROUND

Pre-eclampsia (PE) is one of the leading causes of maternal and fetal morbidity/mortality during pregnancy, and alpha-2-macroglobulin (A2M) is associated with inflammatory signaling; however, the pathophysiological mechanism by which A2M is involved in PE development is not yet understood.

METHODS

Human placenta samples, serum, and corresponding clinical data of the participants were collected to study the pathophysiologic mechanism underlying PE. Pregnant Sprague-Dawley rats were intravenously injected with an adenovirus vector carrying A2M via the tail vein on gestational day (GD) 8.5. Human umbilical artery smooth muscle cells (HUASMCs), human umbilical vein endothelial cells (HUVECs), and HTR-8/SVneo cells were transfected with A2M-expressing adenovirus vectors.

RESULTS

In this study, we demonstrated that A2M levels were significantly increased in PE patient serum, uterine spiral arteries, and feto-placental vasculature. The A2M-overexpression rat model closely mimicked the characteristics of PE (i.e., hypertension in mid-to-late gestation, histological and ultrastructural signs of renal damage, proteinuria, and fetal growth restriction). Compared to the normal group, A2M overexpression significantly enhanced uterine artery vascular resistance and impaired uterine spiral artery remodeling in both pregnant women with early-onset PE and in pregnant rats. We found that A2M overexpression was positively associated with HUASMC proliferation and negatively correlated with cell apoptosis. In addition, the results demonstrated that transforming growth factor beta 1 (TGFβ1) signaling regulated the effects of A2M on vascular muscle cell proliferation described above. Meanwhile, A2M overexpression regressed rat placental vascularization and reduced the expression of angiogenesis-related genes. In addition, A2M overexpression reduced HUVEC migration, filopodia number/length, and tube formation. Furthermore, HIF-1α expression was positively related to A2M, and the secretion of sFLT-1 and PIGF of placental origin was closely related to PE during pregnancy or A2M overexpression in rats.

CONCLUSIONS

Our data showed that gestational A2M overexpression can be considered a contributing factor leading to PE, causing detective uterine spiral artery remodeling and aberrant placental vascularization.

Human umbilical cord mesenchymal stem cells derived extracellular vesicles alleviate salpingitis by promoting M1-to-M2 transformation

Background: With an increasing number of patients experiencing infertility due to chronic salpingitis after Chlamydia trachomatis (CT) infection, there is an unmet need for tissue repair or regeneration therapies. Treatment with human umbilical cord mesenchymal stem cell-derived extracellular vesicles (hucMSC-EV) provides an attractive cell-free therapeutic approach. Methods: In this study, we investigated the alleviating effect of hucMSC-EV on tubal inflammatory infertility caused by CT using in vivo animal experiments. Furthermore, we examined the effect of hucMSC-EV on inducing macrophage polarization to explore the molecular mechanism. Results: Our results showed that tubal inflammatory infertility caused by Chlamydia infection was significantly alleviated in the hucMSC-EV treatment group compared with the control group. Further mechanistic experiments showed that the application of hucMSC-EV induced macrophage polarization from the M1 to the M2 type via the NF-κB signaling pathway, improved the local inflammatory microenvironment of fallopian tubes and inhibited tube inflammation. Conclusion: We conclude that this approach represents a promising cell-free avenue to ameliorate infertility due to chronic salpingitis.

The Role of Inactivated NF-κB in Premature Ovarian Failure

Premature ovarian failure (POF) is defined as deployment of amenorrhea due to the cessation of ovarian function in a woman younger than 40 years old. The pathologic mechanism of POF is not yet well understood, although genetic aberrations, autoimmune damage, and environmental factors have been identified. The current study demonstrated that NF-κB inactivation is closely associated with the development of POF based on the data from literature and cyclophosphamide (Cytoxan)-induced POF mouse model. In the successfully established NF-κB-inactivated mouse model, the results showed the reduced expression of nuclear p65 and the increased expression of IκBα in ovarian granulosa cells; the reduced numbers of antral follicles; the reduction of Ki-67/proliferating cell nuclear antigen-labeled cell proliferation and enhanced Fas/FasL-dependent apoptosis in granulosa cells; the reduced level of E2 and anti-Müllerian hormone; the decreased expression of follicle-stimulating hormone receptor and cytochrome P450 family 19 subfamily A member 1 (CYP19A1) in granulosa cells, which was reversed in the context of blocking NF-κB signaling with BAY 11-7082; and the decreased expressions of glucose-regulated protein 78 (GRP78), activating transcription factor 6, protein kinase R-like endoplasmic reticulum kinase, and inositol-requiring enzyme 1 in granulosa cells. Dual-luciferase reporter assay demonstrated that p50 stimulated the transcription of GRP78, and NF-κB affected the expression of follicle-stimulating hormone receptor and promoted granulosa cell proliferation through GRP78-mediated endoplasmic reticulum stress. Taken together, these data indicate, for the first time, that the inactivation of NF-κB signaling plays an important role in POF.

NF-κB activation impedes the transdifferentiation of hypertrophic chondrocytes at the growth plate of mouse embryos in diabetic pregnancy

BACKGROUND

Diabetes mellitus could cause numerous complications and health problems including abnormality of endochondral bone formation during embryogenesis. However, the underlying mechanisms still remain obscure.

METHODS

Streptozotoci (STZ) was injected to induce pregestational diabetes mellitus (PGDM) mouse model. The femurs of E18.5 mouse embryos from control and PGDM groups were harvested. Morphological staining was implemented to determine the abnormality of the bone development. The expressions of the key genes participating in osteogenesis (e.g., Sox9, Runx2, and Osterix), the NF-κB signaling molecules (e.g., P50, P65, IκBα), and the corresponding regulatory factors (e.g., Bmp2, phospho-p38) were evaluated by immunofluorescence, quantitative PCR and western blot. Finally, in vitro chondrocyte differentiation model was employed to verify the role of NF-κB on the expressions of chondro-osteogenic markers.

RESULTS

Alcian blue/alizarin red double staining and H&E staining demonstrated the restriction of skeletal development and relatively extended hypertrophic zone at growth plate in E18.5 STZ-induced diabetic mouse embryos compared to the control. Immunofluorescent staining and qPCR showed that Sox9 expression increased, while Runx2 and Osterix expressions decreased in the growth plate of the offspring of PGDM mice. Immunofluorescence of P65 manifested the activation of NF-κB signaling in growth plate in PGDM mouse embryos. Furthermore, the relatively extended hypertrophic zone was also observed in the growth plate of the NF-κB-activated transgenic mice, as well as the activated p65 up-regulated the expression of Bmp2 and p-p38. In ATDC5 cells, we could observe the high glucose up-regulated the P50 and P65 expressions and down-regulated IκBα expression, but the high glucose-activated NF-κB signaling could be reversed by addition of Bay (inhibitor of NF-κB signaling). The expression changes of Bmp2, Sox9 and Runx2 in presence of high glucose were resumed too.

CONCLUSION

Our data revealed that NF-κB signaling was involved in mediation effects of dysfunctional trans-differentiation of hypertrophic chondrocytes in the embryonic growth plate induced by maternal diabetic mellitus.

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.

NF-κB and pSTAT3 synergistically drive G6PD overexpression and facilitate sensitivity to G6PD inhibition in ccRCC

Background

Glucose 6-phosphate dehydrogenase (G6PD) serves key roles in cancer cell metabolic reprogramming, and has been reported to be involved in certain carcinogenesis. Previous results from our laboratory demonstrated that overexpressed G6PD was a potential prognostic biomarker in clear cell renal cell carcinoma (ccRCC), the most common subtype of kidney cancer. G6PD could stimulate ccRCC growth and invasion through facilitating reactive oxygen species (ROS)-phosphorylated signal transducer and activator of transcription 3 (pSTAT3) activation and ROS-MAPK-MMP2 axis pathway, respectively. However, the reasons for ectopic G6PD overexpression and the proliferation repressive effect of G6PD inhibition in ccRCC are still unclear.

Methods

The impact of ROS accumulation on NF-κB signaling pathway and G6PD expression was determined by real-time RT-PCR and Western blot in ccRCC cells following treatment with ROS stimulator or scavenger. The regulatory function of NF-κB signaling pathway in G6PD transcription was analyzed by real-time RT-PCR, Western blot, luciferase and ChIP assay in ccRCC cells following treatment with NF-κB signaling activator/inhibitor or lentivirus infection. ChIP and Co-IP assay was performed to demonstrate protein-DNA and protein-protein interaction of NF-κB and pSTAT3, respectively. MTS assay, human tissue detection and xenograft model were conducted to characterize the association between NF-κB, pSTAT3, G6PD expression level and proliferation functions.

Results

ROS-stimulated NF-κB and pSTAT3 signaling over-activation could activate each other, and exhibit cross-talks in G6PD aberrant transcriptional regulation. The underlying mechanism was that NF-κB signaling pathway facilitated G6PD transcription via direct DNA-protein interaction with p65 instead of p50. p65 and pSTAT3 formed a p65/pSTAT3 complex, occupied the pSTAT3-binding site on G6PD promoter, and contributed to ccRCC proliferation following facilitated G6PD overexpression. G6PD, pSTAT3, and p65 were highly expressed and positively correlated with each other in ccRCC tissues, confirming that NF-κB and pSTAT3 synergistically promote G6PD overexpression. Moreover, G6PD inhibitor exhibited tumor-suppressor activities in ccRCC and attenuated the growth of ccRCC cells both in vitro and in vivo.

Conclusion

ROS-stimulated aberrations of NF-κB and pSTAT3 signaling pathway synergistically drive G6PD transcription through forming a p65/pSTAT3 complex. Moreover, G6PD activity inhibition may be a promising therapeutic strategy for ccRCC treatment.

P65 Targets FGFR1 to Regulate the Survival of Ovarian Granulosa Cells

In female mammals, the abnormal apoptosis of ovarian granulosa cells (GCs) impairs follicular development and causes reproductive dysfunction. Many studies have indicated that the FGFR1 gene of the PI3K signaling pathway and the p65 subunit of the transcription factor NF-κB may regulate the proliferation and apoptosis of GCs involved in follicular development. However, little is known about whether p65 regulates the transcription of FGFR1, as well as the biological effects of p65 and FGFR1 on the survival of GCs and follicular development. In porcine follicles and GCs, we found that p65 and FGFR1 were exclusively expressed in the GCs of follicles, and the mRNA and protein levels of p65 and FGFR1 significantly increased from small to large follicles. Both p65 and FGFR1 were found to activate the PI3K signaling pathway, and the expressions of proliferation markers (PCNA and MKI67) and the anti-apoptotic gene BCL2 were significantly increased by p65 and FGFR1. Furthermore, both p65 and FGFR1 were observed to promote cell proliferation and inhibit the cell apoptosis of GCs, and p65 was confirmed to bind at the −348/−338 region of FGFR1 to positively regulate its transcription. Moreover, p65 was further found to enhance the pro-proliferation and anti-apoptotic effects of FGFR1. Taken together, p65 may target the −348/−338 region of FGFR1, promote the transcription of FGFR1, and enhance the pro-proliferation effect and anti-apoptotic effect of FGFR1 to facilitate the growth of follicles. This study will provide useful information for further investigations on the p65-mediated-FGFR1 signaling pathway during folliculogenesis in mammals.