Multifunctional Transcription Factor Research Articles

Role of the multifunctional transcription factor TFII-I in DNA damage repair

The multifunctional transcription factor TFII-I, encoded by the GTF2I gene, is implicated in various biological pathways, and associated with multiple human disorders. Evidence is also mounting to suggest that TFII-I is involved in DNA damage repair pathways. Here I bring together these recent observations and suggest a connection between transcriptional and DNA repair functions of TFII-I.

NF-κB signalling pathways in nucleus pulposus cell function and intervertebral disc degeneration.

Intervertebral disc degeneration (IDD) is a common clinical degenerative disease of the spine. A series of factors, such as inflammation, oxidative stress and mechanical stress, promote degradation of the extracellular matrix (ECM) of the intervertebral discs (IVD), leading to dysfunction and structural destruction of the IVD. Nuclear factor‐κB (NF‐κB) transcription factor has long been regarded as a pathogenic factor of IDD. Therefore, NF‐κB may be an ideal therapeutic target for IDD. As NF‐κB is a multifunctional functional transcription factor with roles in a variety of biological processes, a comprehensive understanding of the function and regulatory mechanism of NF‐κB in IDD pathology will be useful for the development of targeted therapeutic strategies for IDD, which can prevent the progression of IDD and reduce potential risks. This review discusses the role of the NF‐κB signalling pathway in the nucleus pulposus (NP) in the process of IDD to understand pathological NP degeneration further and provide potential therapeutic targets that may interfere with NF‐κB signalling for IDD therapy.

MMTV-LIKE virus and c-myc over-expression are associated with invasive breast cancer.

Development and progression of breast cancer is an outcome of strong interplay between proto-oncogenes as well as environmental factors. Among proto-oncogenes, c-myc, a multifunctional transcription factor (TF), is one of the most highlighted one, whereas among environmental factors Mouse Mammary Tumor Virus (MMTV)-like virus is a widely discussed agent. Both, c-myc and MMTV-like virus, are known to individually correlate with the poor prognosis of breast cancer. However, no study has ever been reported to determine their mutual association in breast cancer patients. In this study, our aim was to quantify and compare c-myc mRNA in MMTV-like virus-positive and virus-negative-histopathological types of breast cancer. At first, biopsy samples of 105 breast cancer patients with known histopathological types were collected and screened for the presence of MMTV-like virus. To quantify mRNA level of c-myc, quantitative-Polymerase Chain Reaction (qPCR) was used. Next, c-myc expression was compared in MMTV-like virus-positive and virus-negative-histopathological types as of breast cancer. Statistical analysis was done using GraphPad Prism 7 Software. Molecular analysis revealed that 69 (65.72%) out of 105 samples were positive for MMTV-like virus. Moreover, invasive types of breast cancer exhibited increased (3-13 folds higher) expression of c-myc as compared to baseline representing normal control comprising of 15 tumor-free biopsy samples of breast cancer patients. Whereas, non-invasive types of breast cancer showed only 1-3 folds increase in the expression of c-myc as compared to normal control. Furthermore, virus-positive and virus-negative samples had different levels of c-myc mRNA. Positive status of MMTV-like virus was noticed to significantly associate with c-myc expression increasing it from 1.87-folds in virus-negative patient samples to 4.31-folds in virus-positive patient samples (p-value: <0.0001). Whereas, increase in the expression of c-myc was only 1.14-folds higher in 2 (13.33%) virus-positive-normal control samples as compared to 13 (86.67%) virus-negative-normal control samples (P-value: <0.01). In conclusion, it is suggested that presence of MMTV-like virus and over-expression of c-myc may be used as markers of invasion of breast cancer.

HbxB Is a Key Regulator for Stress Response and β-Glucan Biogenesis in Aspergillus nidulans.

Homeobox transcription factors are conserved in eukaryotes and act as multi-functional transcription factors in filamentous fungi. Previously, it was demonstrated that HbxB governs fungal development and spore viability in Aspergillus nidulans. Here, the role of HbxB in A. nidulans was further characterized. RNA-sequencing revealed that HbxB affects the transcriptomic levels of genes associated with trehalose biosynthesis and response to thermal, oxidative, and radiation stresses in asexual spores called conidia. A phenotypic analysis found that hbxB deletion mutant conidia were more sensitive to ultraviolet stress. The loss of hbxB increased the mRNA expression of genes associated with β-glucan degradation and decreased the amount of β-glucan in conidia. In addition, hbxB deletion affected the expression of the sterigmatocystin gene cluster and the amount of sterigmatocystin. Overall, these results indicated that HbxB is a key transcription factor regulating trehalose biosynthesis, stress tolerance, β-glucan degradation, and sterigmatocystin production in A. nidulans conidia.

Loss of YY1 expression predicts unfavorable prognosis in stage III colorectal cancer

Yin Yang 1 (YY1), the multifunctional transcription factor, has recently been assigned biological properties related to human malignancies. YY1 can facilitate both tumor suppression and tumor growth. The conflicting role of YY1 in human malignancies is not yet fully explained. In this study, we determined the clinicopathologic significance and prognostic role of YY1 in stage III colorectal cancer (CRC). YY1 expression was evaluated immunohistochemically in tissue microarray from 345 CRCs. YY1 expression was scored by the proportion of tumor cells with nuclear staining into 4 scores (0, none; 1+, ≤10%; 2+, 10 to ≤25%; 3+, >25%). A score of 0 and 1 were considered as loss of expression. Loss of YY1 expression was observed in 49 (14.2%) out of 345 CRCs and was associated with larger tumor size (P = 0.004), tumor deposit (P = 0.008), and higher pathologic tumor (pT) stage (P = 0.004). In stage III group, loss of YY1 expression was associated with larger tumor size (P = 0.027) and tumor deposit (P = 0.011). Kaplan-Meier survival curves revealed no significant difference between patients with YY1 loss and patients with intact YY1 in both cancer-specific survival and recurrence-free survival (P = 0.330 and P = 0.470, respectively). In American Joint Committee on Cancer (AJCC) stage subgroup, loss of YY1 expression was associated with poor recurrence-free survival in AJCC stage III CRC (P = 0.038). Loss of YY1 expression was significantly associated with aggressive phenotypes and poor patient outcome in AJCC stage III CRC.

Identification of the HECT E3 ligase UBR5 as a regulator of MYC degradation using a CRISPR/Cas9 screen

MYC oncoprotein is a multifunctional transcription factor that regulates the expression of a large number of genes involved in cellular growth, proliferation and metabolism. Altered MYC protein level lead to cellular transformation and tumorigenesis. MYC is deregulated in > 50% of human cancers, rendering it an attractive drug target. However, direct inhibition of this class of proteins using conventional small molecules is challenging due to their intrinsically disordered state. To discover novel posttranslational regulators of MYC protein stability and turnover, we established a genetic screen in mammalian cells by combining a fluorescent protein-based MYC abundance sensor, CRISPR/Cas9-based gene knockouts and next-generation sequencing. Our screen identifies UBR5, an E3 ligase of the HECT-type family, as a novel regulator of MYC degradation. Even in the presence of the well-described and functional MYC ligase, FBXW7, UBR5 depletion leads to accumulation of MYC in cells. We demonstrate interaction of UBR5 with MYC and reduced K48-linked ubiquitination of MYC upon loss of UBR5 in cells. Interestingly, in cancer cell lines with amplified MYC expression, depletion of UBR5 resulted in reduced cell survival, as a consequence of MYC stabilization. Finally, we show that MYC and UBR5 are co-amplified in more than 40% of cancer cells and that MYC copy number amplification correlates with enhanced transcriptional output of UBR5. This suggests that UBR5 acts as a buffer in MYC amplified settings and protects these cells from apoptosis.

Multifunctional transcription factor CytR of Vibrio cholerae is important for pathogenesis.

Vibrio cholerae, the Gram-negative facultative pathogen, resides in the aquatic environment and infects humans and causes diarrhoeagenic cholera. Although the environment differs drastically, V. cholerae thrives in both of these conditions aptly and chitinases play a vital role in their persistence and nutrient acquisition. Chitinases also play a role in V. cholerae pathogenesis. Chitinases and its downstream chitin utilization genes are regulated by sensor histidine kinase ChiS, which also plays a significant role in pathogenesis. Recent exploration suggests that CytR, a transcription factor of the LacI family in V. cholerae, also regulates chitinase secretion in environmental conditions. Since chitinases and chitinase regulator ChiS is involved in pathogenesis, CytR might also play a significant role in pathogenicity. However, the role of CytR in pathogenesis is yet to be known. This study explores the regulation of CytR on the activation of ChiS in the presence of mucin and its role in pathogenesis. Therefore, we created a CytR isogenic mutant strain of V. cholerae (CytR¯) and found considerably less β-hexosaminidase enzyme production, which is an indicator of ChiS activity. The CytR¯ strain greatly reduced the expression of chitinases chiA1 and chiA2 in mucin-supplemented media. Electron microscopy showed that the CytR¯ strain was aflagellate. The expression of flagellar-synthesis regulatory genes flrB, flrC and class III flagellar-synthesis genes were reduced in the CytR¯ strain. The isogenic CytR mutant showed less growth compared to the wild-type in mucin-supplemented media as well as demonstrated highly retarded motility and reduced mucin-layer penetration. The CytR mutant revealed decreased adherence to the HT-29 cell line. In animal models, reduced fluid accumulation and colonization were observed during infection with the CytR¯ strain due to reduced expression of ctxB, toxT and tcpA. Collectively these data suggest that CytR plays an important role in V. cholerae pathogenesis.

GTF2IRD1 overexpression promotes tumor progression and correlates with less CD8+ T cells infiltration in pancreatic cancer.

Background: General Transcription Factor II-I Repeat Domain-Containing Protein 1 (GTF2IRD1) is a member of the GTF21 gene family, which encodes a set of multifunctional transcription factors. However, the potential function of GTF2IRD1 in pancreatic cancer (PC) still remains unknown. Study on GTF2IRD1 might provide a new insight into the carcinogenesis and therapeutics of PC.Methods: In the current study, the clinical significance and potential biological of GTF2IRD1 were evaluated by bioinformatics analysis. The oncogenic role of GTF2IRD1 in PC was also determined using in vitro studies. Possible associations between GTF2IRD1 expression and tumor immunity were analyzed using ESTIMATE algorithm and single-sample Gene Set Enrichment Analysis (ssGSEA).Results: GTF2IRD1 expression was significantly up-regulated in tumor tissues, and positively associated with higher histologic grade, higher American Joint Committee on Cancer (AJCC) stage, and worse prognosis. Function enrichment analysis demonstrated that GTF2IRD1 may be involved in pancreatic adenocarcinoma pathway, TGF-β signaling pathway, and tumor-infiltrating lymphocyte (TIL) related biological functions, such as T-cell receptor signaling pathway, leukocyte transendothelial migration, resistin as a regulator of inflammation, and regulation of leukocyte-mediated cytotoxicity. Knockdown of GTF2IRD1 expression inhibited cancer cell proliferation, colony formation, and invasion in vitro. ESTIMATE algorithm and ssGSEA demonstrated that GTF2IRD1 expression negatively correlated with the infiltration and anti-tumor activity of TILs, especially for CD8+ T cells.Conclusion: The study demonstrates that GTF2IRD1 overexpression promotes tumor progression and correlates with less CD8+ T cells infiltration in PC.

A novel protein upstream stimulatory factor 2 identified in lamprey, Lethenteron reissneri.

Upstream stimulatory factors are kinds of multi-functional transcription factors, which are expressed in eukaryotes widely, including Upstream stimulatory factor 1 (USFl) and upstream stimulatory factor 2 (USF2). USF protein has a typical basic helix-loop-helix leucine zipper (b-HLH-LZ) structure, which is involved in cell cycle, cell proliferations, glucose and lipid metabolism, and other biochemical processes. Although the USF family is an important regulator of cellular processes, little is known about the USF genes of lampreys, especially their evolutionary relationships, expression profiles, and biological functions. Here, an upstream stimulatory factor 2 (USF2) homolog from lamprey (Lethenteron reissneri) was identified and characterized (designated as L-USF2) because it is closer to USF2 subfamily than to USF1 subfamily. The cDNA fragment of L-USF2 has an open reading frame (ORF) of 765-bp length, encodes 254 amino acids, and contains an HLH domain at the c-terminal of amino acids. Meanwhile, motifs and genetic structure analysis reveal that USF2 gene exons are conserved. Moreover, the 3D structure analysis indicates that L-USF2 adopts the general USF2 folding and has a high structural similarity with H-USF2. The synteny results showed that the L-USF2 adjacent gene changed greatly compared with the jaw vertebrates. By real-time quantitative experiment and Western blot analysis, we found that L-USF2 gene played a significant role in the immune responses. This study not only provides us with a further understanding of the evolution and function of the USF gene family but also provides a basis for exploring its immune responses and immune defenses in lampreys.

Heterologous Expression of Poplar WRKY18/35 Paralogs in Arabidopsis Reveals Their Antagonistic Regulation on Pathogen Resistance and Abiotic Stress Tolerance via Variable Hormonal Pathways.

WRKY transcription factors (WRKY TFs) are one of the largest protein families in plants, and most of them play vital roles in response to biotic and abiotic stresses by regulating related signaling pathways. In this study, we isolated two WRKY TF genes PtrWRKY18 and PtrWRKY35 from Populus trichocarpa and overexpressed them in Arabidopsis. Expression pattern analyses showed that PtrWRKY18 and PtrWRKY35 respond to salicylic acid (SA), methyl JA (MeJA), abscisic acid (ABA), B. cinereal, and P. syringae treatment. The transgenic plants conferred higher B. cinerea tolerance than wild-type (WT) plants, and real-time quantitative (qRT)-PCR assays showed that PR3 and PDF1.2 had higher expression levels in transgenic plants, which was consistent with their tolerance to B. cinereal. The transgenic plants showed lower P. syringae tolerance than WT plants, and qRT-PCR analysis (PR1, PR2, and NPR1) also corresponded to this phenotype. Germination rate and root analysis showed that the transgenic plants are less sensitive to ABA, which leads to the reduced tolerance to osmotic stress and the increase of the death ratio and stomatal aperture. Compared with WT plants, a series of ABA-related genes (RD29A, ABO3, ABI4, ABI5, and DREB1A) were significantly down-regulated in PtrWRKY18 and PtrWRKY35 overexpression plants. All of these results demonstrated that the two WRKY TFs are multifunctional transcription factors in plant resistance.

Molecular Topology of RNA Polymerase I Upstream Activation Factor.

Upstream activation factor (UAF) is a multifunctional transcription factor in Saccharomyces cerevisiae that plays dual roles in activating RNA polymerase I (Pol I) transcription and repression of Pol II. For Pol I, UAF binds to a specific upstream element in the ribosomal DNA (rDNA) promoter and interacts with two other Pol I initiation factors, the TATA-binding protein (TBP) and core factor (CF). We used an integrated combination of chemical cross-linking mass spectrometry (CXMS), molecular genetics, protein biochemistry, and structural modeling to understand the topological framework responsible for UAF complex formation. Here, we report the molecular topology of the UAF complex, describe new structural and functional domains that play roles in UAF complex integrity, assembly, and biological function, and provide roles for previously identified UAF domains that include the Rrn5 SANT and histone fold domains. We highlight the role of new domains in Uaf30 that include an N-terminal winged helix domain and a disordered tethering domain as well as a BORCS6-like domain found in Rrn9. Together, our results reveal a unique network of topological features that coalesce around a histone tetramer-like core to form the dual-function UAF complex.

YAP-Mediated Recruitment of YY1 and EZH2 Represses Transcription of Key Cell-Cycle Regulators.

The Hippo pathway regulates cell proliferation and organ size through control of the transcriptional regulators YAP (yes-associated protein) and TAZ. Upon extracellular stimuli such as cell-cell contact, the pathway negatively regulates YAP through cytoplasmic sequestration. Under conditions of low cell density, YAP is nuclear and associates with enhancer regions and gene promoters. YAP is mainly described as a transcriptional activator of genes involved in cell proliferation and survival. Using a genome-wide approach, we show here that, in addition to its known function as a transcriptional activator, YAP functions as a transcriptional repressor by interacting with the multifunctional transcription factor Yin Yang 1 (YY1) and Polycomb repressive complex member enhancer of zeste homologue 2 (EZH2). YAP colocalized with YY1 and EZH2 on the genome to transcriptionally repress a broad network of genes mediating a host of cellular functions, including repression of the cell-cycle kinase inhibitor p27, whose role is to functionally promote contact inhibition. This work unveils a broad and underappreciated aspect of YAP nuclear function as a transcriptional repressor and highlights how loss of contact inhibition in cancer is mediated in part through YAP repressive function. SIGNIFICANCE: This study provides new insights into YAP as a broad transcriptional repressor of key regulators of the cell cycle, in turn influencing contact inhibition and tumorigenesis.

The zinc finger transcription factors Bbctf1α and Bbctf1β regulate the expression of genes involved in lipid degradation and contribute to stress tolerance and virulence in a fungal insect pathogen.

To initiate insect infection, entomopathogenic fungi produce diverse cuticle-degrading enzymes. Of those, lipolytic enzymes participate in epicuticular lipid hydrolysis and thus facilitate fungal penetration through the outermost cuticular barrier of the insect host. The Far/CTF1-type zinc finger transcription factors play an important role in the regulation of lipolytic activity and fungal pathogenicity in plant pathogens but remain functionally unknown in fungal insect pathogens. Two Far/CTF1-type transcription factor Bbctf1α and Bbctf1β, which are essential for differential expression of genes involved in the fungal lipid degradation, were identified and functionally characterized in a fungal entomopathogen Beauveria bassiana. Disruption of each gene led to drastic losses of extracellular lipolytic activities under lipidic substrate-inducing conditions, followed by remarkable phenotypic defects associated with the fungal biocontrol potential. These defects mainly included severe impairments of mycelial growth and conidium formation, and drastic losses of tolerance to the stresses of oxidation and cell wall perturbation during colony growth under either normal or induction conditions. Bioassays showed that the virulence of each disruption mutant on the greater wax moth was remarkably attenuated in topical immersion. However, there was no significant difference in intrahemolymph injection when the cuticle penetration process was bypassed. Bbctf1α and Bbctf1β are multifunctional transcription factors that play vital roles in the regulation of fungal lipid utilization and contribute to the vegetative growth, sporulation capacity, environmental fitness and pest control potential in B. bassiana. © 2020 Society of Chemical Industry.

MYC regulates coelomocytes apoptosis by targeting Bax expression in sea cucumber Apostichopus japonicus

Myelocytomatosis viral oncogene (MYC), a multifunctional transcription factor, (TF) exerts various physiological and pathological effects on animals. AjMYC could induce coelomocyte apoptosis in Apostichopus japonicus, but the underlying molecular mechanism remains poorly understood. In this study, the promoter sequence of apoptosis regulator Bcl-2-associated X (Bax) was cloned by genomic walking. The AjBax promoter region spaning 1189 bp, containing several transcription factor binding sites, included four potential E-boxes (−1030 bp to −1019 bp, −785 bp to −774 bp, −570 bp to −559 bp, −100 bp to −89 bp), two P53 binding sites (−439 bp to −430 bp, −845 bp to −836 bp), and one NF-κB site (−191 bp to −182 bp). Transient transfection of EPC cells with 5′–deletion constructs linked to luciferase reporter revealed that the region −1189/+454 contributed importantly to the expression of the AjBax. In addition, the AjBax promoter was induced by LPS, PGN or MAN. The four potential MYC binding sites were cotransfected with AjMYC in EPC cell whether AjMYC could activate AjBax expression as a transcriptional factor. Only P1 (−1189/+454) fragment containing the first MYC binding site transfection increased the luciferase activity by 2.08-fold (p < 0.01) compared with the control. The first MYC binding site −1030/−1019 was essential to induce AjBax transcription. Further functional assay indicated that AjBax was significantly induced by 3.54-fold increase (p < 0.01) after AjMYC overexpression in sea cucumber coelomocytes. All our findings supported that AjMYC could regulate coelomocyte apoptosis by directly targeting AjBax expression in A. japonicus.

Abstract 844: β IV -spectrin Regulates Cardiac Fibroblast Phenotype, Fibrosis, and Cardiac Function

Increased fibrosis is associated with cardiac dysfunction and arrhythmias. Activation of quiescent cardiac fibroblasts (CFs) occurs in response to injury although the underlying mechanistic pathways remain unclear. The cytoskeletal protein β IV -spectrin has been shown to control targeting and activity of the multifunctional transcription factor Signal Transducer and Activator of Transcription 3 (STAT3) for maladaptive remodeling. The mechanism linking spectrin dysfunction to altered STAT3 signaling, fibrosis, and function remains unknown. The objective of this study was to investigate the role of stress-induced disruption of β IV -spectrin/STAT3 complex in modulating CF phenotype, fibrosis, and cardiac function. Cardiac function (echocardiography) and fibrosis (Masson’s trichrome) were evaluated in adult wildtype (WT) and qv 4J mice expressing truncated β IV -spectrin lacking STAT3 interaction. A subset of WT mice were subjected to 6 wks of transaortic constriction (TAC) to induce heart failure. From these groups, CFs were isolated from ventricles and analyzed for STAT3 localization, gene expression, and activity. CFs were treated with selective STAT3 inhibitor S3I-201 (100μM) or transfected for 72 hrs with β IV -spectrin fragment from repeat 10 to C-terminus (β IV,10-C , contains STAT3 binding motif). Ejection fraction was decreased in qv 4J and WT TAC relative to WT baseline (49.5±0.85% vs 34.9±2.2% vs 63.2±0.60% respectively, p&lt;0.05, N=5. Ventricular fibrosis was augmented in qv 4J and WT TAC compared to WT baseline (2.4±0.09% vs 3.2±0.25% vs 0.48±0.01% respectively, p&lt;0.05, N=5). qv 4J CFs showed STAT3 mislocalization (49.7±10.7% nuclear accumulation vs 5.3±.1.8% in WT, p&lt;0.05, N=5) with higher STAT3 transcriptional activity (2.6±0.17-fold increase over WT, p&lt;0.05, N=9). In parallel, qv 4J CFs displayed elevated expression of fibrotic genes associated with CF activation. At the functional level, qv 4J CFs showed increased proliferation (1.9±0.19-fold increase over WT at 24 hrs, p&lt;0.05, N=4). STAT3 inhibition with S31-201 or transfection with β IV,10-C normalized gene expression and proliferation in qv 4J CFs compared to WT. These studies identify a requirement of β IV -spectrin for normal STAT3 signaling and quiescent phenotype in CFs.

NF-κB Signaling Pathways in Osteoarthritic Cartilage Destruction.

Osteoarthritis (OA) is a type of joint disease associated with wear and tear, inflammation, and aging. Mechanical stress along with synovial inflammation promotes the degradation of the extracellular matrix in the cartilage, leading to the breakdown of joint cartilage. The nuclear factor-kappaB (NF-κB) transcription factor has long been recognized as a disease-contributing factor and, thus, has become a therapeutic target for OA. Because NF-κB is a versatile and multi-functional transcription factor involved in various biological processes, a comprehensive understanding of the functions or regulation of NF-κB in the OA pathology will aid in the development of targeted therapeutic strategies to protect the cartilage from OA damage and reduce the risk of potential side-effects. In this review, we discuss the roles of NF-κB in OA chondrocytes and related signaling pathways, including recent findings, to better understand pathological cartilage remodeling and provide potential therapeutic targets that can interfere with NF-κB signaling for OA treatment.

Src-mediated crosstalk between FXR and YAP protects against renal fibrosis.

Renal fibrosis is the common pathway of chronic kidney disease progression. The nuclear receptor farnesoid X receptor [FXR, NR1H4 (nuclear receptor subfamily 1 group member 4)], a multifunctional transcription factor, plays a pivotal role in protecting against fibrosis. However, the mechanisms underlying these antifibrotic actions of FXR in kidney disease are largely unknown. Here, we show that agonist GW4064-mediated FXR activation inhibits the activity of the nonreceptor tyrosine kinase Src (proto-oncogene tyrosine-protein kinase), which is critical for regulation of yes-associated protein (YAP) phosphorylation and nuclear localization in renal fibrosis. Activation of FXR suppressed renal fibrosis and Tyr416-Src phosphorylation in TGF-β-treated human renal proximal tubule epithelial (HK2) cells. Moreover, GW4064 treatment in HK2 cells increased Ser127 phosphorylation, cytosolic accumulation of YAP, and interaction of the hippo core kinases (Ste20-like kinase 1, large tumor suppressor kinase 1, and salvador homolog 1). Inhibition of Src using PP2 (Src kinase inhibitor) prevented renal fibrosis and increased Ser127 phosphorylation and cytosolic accumulation of YAP. The expression of fibrosis markers, inflammatory genes, and YAP target genes was increased in the kidneys of FXR knockout mice compared with those of wild-type mice. In addition, GW4064 or WAY-362450 (turofexorate isopropyl) treatment protected against unilateral ureteral obstruction-induced renal fibrosis. Collectively, our data support the novel conclusion that Src-mediated crosstalk between FXR and YAP protects against renal fibrosis, making this pathway a possible therapeutic target for chronic kidney disease.-Kim, D.-H., Choi, H.-I., Park, J. S., Kim, C. S., Bae, E. H., Ma, S. K., Kim, S. W. Src-mediated crosstalk between FXR and YAP protects against renal fibrosis.

SUN-133 G-protein Pathway Suppressor 2 (GPS2) Enhanced the Large Conductance Ca2+ Activated Potassium (BK) Channels Activity through modulating WNK4 Ubiquitination

BK channel plays an important role in renal potassium secretion. G-protein pathway suppressor 2 (GPS2) is a multifunctional protein and transcriptional regulation factor that is involved in the G-protein mitogen-activated protein kinase (MAPK) signaling pathway. We have previously reported that WNK4 inhibits BK channel activity by stimulating ERK1/2 and p38 signaling pathways. We have recently shown that GPS2 enhances BK channel activity and its protein expression by reducing ERK1/2 signaling-mediated degradation of the channel.

Thyroid Hormone Protects Primary Cortical Neurons Exposed to Hypoxia by Reducing DNA Methylation and Apoptosis.

Traumatic brain injury (TBI) is associated with disruption of cerebral blood flow leading to localized brain hypoxia. Thyroid hormone (TH) treatment, administered shortly after injury, has been shown to promote neural protection in rodent TBI models. The mechanism of TH protection, however, is not established. We used mouse primary cortical neurons to investigate the effectiveness and possible pathways of T3-promoted cell survival after exposure to hypoxic injury. Cultured primary cortical neurons were exposed to hypoxia (0.2% oxygen) for 7 hours with or without T3 (5 nM). T3 treatment enhanced DNA 5-hydroxymethylcytosine levels and attenuated the hypoxia-induced increase in DNA 5-methylcytosine (5-mc). In the presence of T3, mRNA expression of Tet family genes was increased and DNA methyltransferase (Dnmt) 3a and Dnmt3b were downregulated, compared with conditions in the absence of T3. These T3-induced changes decreased hypoxia-induced DNA de novo methylation, which reduced hypoxia-induced neuronal damage and apoptosis. We used RNA sequencing to characterize T3-regulated genes in cortical neurons under hypoxic conditions and identified 22 genes that were upregulated and 15 genes that were downregulated. Krüppel-like factor 9 (KLF9), a multifunctional transcription factor that plays a key role in central nervous system development, was highly upregulated by T3 treatment in hypoxic conditions. Knockdown of the KLF9 gene resulted in early apoptosis and abolished the beneficial role of T3 in neuronal survival. KLF9 mediates, in part, the neuronal protective role of T3. T3 treatment reduces hypoxic damage, although pathways that reduce DNA methylation and apoptosis remain to be elucidated.

Identification and investigation on the foxc1-regulated mrnas and mirnas in osteogenic differentiation of mouse preosteoblastic cells

Background: Foxc1, a multi-functional transcription factor belonging to the forkhead box gene family, is essential for normal development and patterning of bones originated from endochondral and intramembranous origins.