Genome-wide analyses reveal the regulatory roles of DNA methylation-regulated alternative promoter transcripts in breast cancer.

A certain proportion of genes are regulated by multiple, distinct promoters, revealing a dynamic landscape of the cancer transcriptome. However, the contribution of alternative promoters (APs) in breast cancer (BRCA) remains largely unexplored. Here, we identified 3654 genes with multiple promoters in BRCA patients, and 53 of them could generate distinct AP transcripts that are dysregulated and prognosis-related in BRCA, namely prognosis-related dysregulated AP (prdeAP) transcripts. Interestingly, when we searched for the genomic signatures of these prdeAP genes, we found that the promoter regions of 92% of the prdeAP genes were enriched with abundant DNA methylation signals. Through further bioinformatic analysis and experimental validation, we showed that AP selections of TANK, UNKL, CCL28, and MAP1LC3A were regulated by DNA methylation upon their corresponding promoter regions. Functionally, by overexpressing AP variants of TANK, we found that TANK|55731 could dramatically suppress MDA-MB-231 cell proliferation and migration. Meanwhile, pan-cancer survival analyses suggested that AP variants of TANK provided more accurate prognostic predictive ability than TANK gene in a variety of tumor types, including BRCA. Together, by uncovering the DNA methylation-regulated AP transcripts with tumor prognostic features, our work revealed a novel layer of regulators in BRCA progression and provided potential targets that served as effective biomarkers for anti-BRCA treatment.

Long noncoding RNA PM maintains cerebellar synaptic integrity and Cbln1 activation via Pax6/Mll1-mediated H3K4me3.

Recent studies have shown that long noncoding RNAs (lncRNAs) are critical regulators in the central nervous system (CNS). However, their roles in the cerebellum are currently unclear. In this work, we identified the isoform 204 of lncRNA Gm2694 (designated as lncRNA-Promoting Methylation (lncRNA-PM)) is highly expressed in the cerebellum and derived from the antisense strand of the upstream region of Cerebellin-1 (Cbln1), a well-known critical cerebellar synaptic organizer. LncRNA-PM exhibits similar spatiotemporal expression pattern as Cbln1 in the postnatal mouse cerebellum and activates the transcription of Cbln1 through Pax6/Mll1-mediated H3K4me3. In mouse cerebellum, lncRNA-PM, Pax6/Mll1, and H3K4me3 are all associated with the regulatory regions of Cbln1. Knockdown of lncRNA-PM in cerebellum causes deficiencies in Cbln1 expression, cerebellar synaptic integrity, and motor function. Together, our work reveals an lncRNA-mediated transcriptional activation of Cbln1 through Pax6-Mll1-H3K4me3 and provides novel insights of the essential roles of lncRNA in the cerebellum.

The IFNγ-PDL1 Pathway Enhances CD8T-DCT Interaction to Promote Hypertension.

BACKGROUND: Renal T cells contribute importantly to hypertension, but the underlying mechanism is incompletely understood. We reported that CD8Ts directly stimulate distal convoluted tubule cells (DCTs) to increase NCC (sodium chloride co-transporter) expression and salt reabsorption. However, the mechanistic basis of this pathogenic pathway that promotes hypertension remains to be elucidated. METHODS: We used mouse models of DOCA+salt (DOCA) treatment and adoptive transfer of CD8+ T cells (CD8T) from hypertensive animals to normotensive animals in in vivo studies. Co-culture of mouse DCTs and CD8Ts was used as in vitro model to test the effect of CD8T activation in promoting NCC-mediated sodium retention and to identify critical molecular players contributing to the CD8T-DCT interaction. Interferon (IFNγ)-KO mice and mice receiving renal tubule-specific knockdown of PDL1 were used to verify in vitro findings. Blood pressure was continuously monitored via radio-biotelemetry, and kidney samples were saved at experimental end points for analysis. RESULTS: We identified critical molecular players and demonstrated their roles in augmenting the CD8T-DCT interaction leading to salt-sensitive hypertension. We found that activated CD8Ts exhibit enhanced interaction with DCTs via IFN-γ-induced upregulation of MHC-I and PDL1 in DCTs, thereby stimulating higher expression of NCC in DCTs to cause excessive salt retention and progressive elevation of blood pressure. Eliminating IFN-γ or renal tubule-specific knockdown of PDL1 prevented T cell homing into the kidney, thereby attenuating hypertension in 2 different mouse models. CONCLUSIONS: Our results identified the role of activated CD8Ts in contributing to increased sodium retention in DCTS through the IFNγ-PDL1 pathway. These findings provide a new mechanism for T cell involvement in the pathogenesis of hypertension and reveal novel therapeutic targets.

NEK2 promotes TP53 ubiquitination to enhance the proliferation and migration of TP53 wild-type glioblastoma cells.

The most common primary malignant tumor in the adult brain is glioblastoma multiforme (GBM); however, its underlying pathogenic mechanism remains elusive. The never in mitosis (NIMA)-related kinase 2 (NEK2) has been closely associated with the prognosis of various malignancies. Nevertheless, the complete elucidation of NEK2's potential clinical value, particularly in glioma prognosis and development, remains lacking. U87MG and A172 glioblastoma cells were infected with sh-NEK2 lentivirus or oe-NEK2 plasmid to investigate the effect of NEK2 on cell proliferation, migration, and invasion. Cell viability was measured using CCK-8 and colony formation assays, while Transwell assay was utilized to assess cell migration and invasion. Protein expression levels were determined through western blot analysis. Additionally, CGGA and TCGA databases were used for bioinformatics analysis in order to examine the NEK2 expression. Through comprehensive bioinformatics analysis, we identified elevated mRNA expression levels of NEK2 in gliomas compared to normal tissues, which correlated with poor prognosis among glioma patients. Moreover, functional experiments revealed that silencing NEK2 suppressed glioma cell proliferation while overexpression of NEK2 promoted migration and invasion capabilities. Finally, our study uncovered that NEK2 regulates the malignant progression of TP53 wild-type glioblastoma by facilitating TP53 ubiquitination.

The nuclear receptor subfamily 4 group A1 in human disease.

Nuclear receptor 4A1 (NR4A1), a member of the NR4A subfamily, acts as a gene regulator in a wide range of signaling pathways and responses to human diseases. Here, we provide a brief overview of the current functions of NR4A1 in human diseases and the factors involved in its function. A deeper understanding of these mechanisms can potentially improve drug development and disease therapy.

The impact of RNA binding proteins and the associated long non-coding RNAs in the TCA cycle on cancer pathogenesis.

The tricarboxylic acid (TCA) cycle is a central route for generating cellular energy and precursors for biosynthetic pathways. Emerging evidences have shown that the aberrations of metabolic enzymes which affect the integrity of TCA cycle are implicated in various tumour pathological processes. Interestingly, several TCA enzymes exhibit the characteristics of RNA binding properties, and their long non-coding RNA (lncRNA) partners play critical regulatory roles in regulating the function of TCA cycle and tumour progression. In this review, we will discuss the functional roles of RNA binding proteins and their lncRNA partners in TCA cycle, with emphasis placed on the cancer progression. A further understanding of RNA binding proteins and their lncRNA partners in TCA cycle, as well as their molecular mechanisms in oncogenesis, will aid in developing novel layers of metabolic targets for cancer therapy in the near future.Abbreviations: CS: citrate synthase. AH: aconitase, including ACO1, and ACO2. IDH: isocitrate dehydrogenase, including IDH1, IDH2, and IDH3. KGDHC: α-ketoglutarate dehydrogenase complex, including OGDH, DLD, and DLST. SCS: succinyl-CoA synthase, including SUCLG1, SUCLG2, and SUCLA2. SDH: succinate dehydrogenase, including SDHA, SDHB, SDHC, and SDHD. FH: fumarate hydratase. MDH: malate dehydrogenase, including MDH1 and MDH2. PC: pyruvate carboxylase. ACLY: ATP Citrate Lyase. NIT: nitrilase. GAD: glutamate decarboxylase. ABAT: 4-aminobutyrate aminotransferase. ALDH5A1: aldehyde dehydrogenase 5 family member A1. ASS: argininosuccinate synthase. ASL: adenylosuccinate synthase. DDO: D-aspartate oxidase. GOT: glutamic-oxaloacetic transaminase. GLUD: glutamate dehydrogenase. HK: hexokinase. PK: pyruvate kinase. LDH: lactate dehydrogenase. PDK: pyruvate dehydrogenase kinase. PDH: pyruvate dehydrogenase complex. PHD: prolyl hydroxylase domain protein.

A pair of long intergenic non-coding RNA LINC00887 variants act antagonistically to control Carbonic Anhydrase IX transcription upon hypoxia in tongue squamous carcinoma progression.

BACKGROUND: Long noncoding RNAs (lncRNAs) are important regulators in tumor progression. However, their biological functions and underlying mechanisms in hypoxia adaptation remain largely unclear. RESULTS: Here, we established a correlation between a Chr3q29-derived lncRNA gene and tongue squamous carcinoma (TSCC) by genome-wide analyses. Using RACE, we determined that two novel variants of this lncRNA gene are generated in TSCC, namely LINC00887_TSCC_short (887S) and LINC00887_TSCC_long (887L). RNA-sequencing in 887S or 887L loss-of-function cells identified their common downstream target as Carbonic Anhydrase IX (CA9), a gene known to be upregulated by hypoxia during tumor progression. Mechanistically, our results showed that the hypoxia-augmented 887S and constitutively expressed 887L functioned in opposite directions on tumor progression through the common target CA9. Upon normoxia, 887S and 887L interacted. Upon hypoxia, the two variants were separated. Each RNA recognized and bound to their responsive DNA cis-acting elements on CA9 promoter: 887L activated CA9's transcription through recruiting HIF1α, while 887S suppressed CA9 through DNMT1-mediated DNA methylation. CONCLUSIONS: We provided hypoxia-permitted functions of two antagonistic lncRNA variants to fine control the hypoxia adaptation through CA9.

Yiqi Huoxue Tongluo recipe regulates NR4A1 to improve renal mitochondrial function in unilateral ureteral obstruction (UUO) rats.

CONTEXT: Yiqi Huoxue Tongluo recipe (YHTR) is a traditional Chinese medicine for the treatment of chronic kidney disease, but its exact mechanism is not clear. OBJECTIVES: To monitor the potential improvement of renal mitochondrial function in unilateral ureteral obstruction (UUO) rats by regulating NR4A1 using the YHTR. MATERIALS AND METHODS: Wistar rats were randomly divided into four groups: sham, UUO (left ureteral ligation for 14 days), eplerenone (EPL) (UUO + EPL), and YHTR (UUO + YHTR). UUO rats were established and intragastrically administered EPL (100 mg/day/kg) or YHTR (11.7 g/day/kg) for 14 days. The expression of related proteins in kidneys was detected by immunohistochemistry, western blot, RT-PCR, and chemical colorimetric assay, respectively. RESULTS: In vivo, YHTR treatment reduced the levels of BUN and Scr (by 17.9% and 23.5%) in UUO rats. Moreover, YHTR improved the renal mitochondrial function via increasing key enzymes of the tricarboxylic acid (TCA) cycle (p < 0.05) and activity of the mitochondrial complex (I-V) (by 30.8%, 29.1%, 19.7%, 35.9%, and 22.4%) in UUO rats. Compared with the UUO group, the expression of NR4A1 and Bcl-2 were significantly increased (p < 0.05), the expression of caspase-3 and caspase-9 were significantly decreased (p < 0.05) in the YHTR group. YHTR could upregulate key enzymes of the TCA cycle via promoting NR4A1 expression in HK2 cells, leading to inhibition of TGF-ß1 induced cell apoptosis. CONCLUSIONS: YHTR significantly improved the development of CKD; this study may provide new ideas for the pathogenesis of CKD and new strategies for the development of new drugs against CKD.

A long noncoding RNA cluster-based genomic locus maintains proper development and visual function.

Long noncoding RNAs (lncRNAs) represent a group of regulatory RNAs that play critical roles in numerous cellular events, but their functional importance in development remains largely unexplored. Here, we discovered a series of previously unidentified gene clusters harboring conserved lncRNAs at the nonimprinting regions in brain (CNIBs). Among the seven identified CNIBs, human CNIB1 locus is located at Chr 9q33.3 and conserved from Danio rerio to Homo sapiens. Chr 9q33.3-9q34.11 microdeletion has previously been linked to human nail-patella syndrome (NPS) which is frequently accompanied by developmental and visual deficiencies. By generating CNIB1 deletion alleles in zebrafish, we demonstrated the requirement of CNIB1 for proper growth and development, and visual activities. Furthermore, we found that the role of CNIB1 on visual activity is mediated through a regulator of ocular development-lmx1bb. Collectively, our study shows that CNIB1 lncRNAs are important for zebrafish development and provides an lncRNA cluster-mediated pathophysiological mechanism for human Chr 9q33.3-9q34.11 microdeletion syndrome.

Tannic acid-directed synthesis of magnetic and boronic acid-functionalized metal-organic frameworks for selective extraction and quantification of catecholamines in human urine.

A novel magnetic borate-functionalized metal-organic framework nanocomposite was designed and fabricated for selective enrichment of catecholamines from human urine. Firstly, the polytannic acid (PTA) layer with natural low-cost and ecofriendly polyphenol tannic acid as the organic ligand and Fe3+ as the cross-linker was coated onto the surface of Fe3O4. Then, the borate-functionalized metal-organic framework (MIL-100(Fe)-B) with 5-boronobenzene-1,3-dicarboxylic acid as a ligand fragment was modified onto the PTA-coated Fe3O4 through a metal-ligand-fragment coassembly strategy. The obtained smart porous adsorbent Fe3O4@PTA@MIL-100(Fe)-B was confirmed by means of several characterization methods and then applied as an effective magnetic solid phase extraction (MSPE) sorbent for specific extraction of trace catecholamines in human urine. The Plackett-Burman design was used for screening the variables significantly affecting the extraction efficiency. Then, the significant factors were further investigated by the Box-Behnken design to determine the optimal extraction conditions. Under the optimal conditions, a method for selective MSPE combined with high-performance liquid chromatography with a fluorescence detector for the quantitation of catecholamines in human urine was developed and validated. With the proposed method, the linearity range was from 0.500 to 500 ng mL-1 for norepinephrine and epinephrine and from 1.00 to 500 ng mL-1 for dopamine. The detection limits were 0.050, 0.11, and 0.20 ng mL-1 for norepinephrine, epinephrine, and dopamine, respectively. The recoveries from spiking experiments varied from 91.5 to 108% with relative standard deviations (RSDs) of 0.80-4.8%. The established method is rapid, sensitive, accurate, inexpensive, and ecofriendly and was successfully applied to the determination of the target catecholamines in human urine samples.

Annotation and cluster analysis of spatiotemporal- and sex-related lncRNA expression in rhesus macaque brain.

Long noncoding RNAs (lncRNAs) mediate important epigenetic regulation in a wide range of biological processes and diseases. We applied comprehensive analyses of RNA-seq and CAGE-seq (cap analysis of gene expression and sequencing) to characterize the dynamic changes in lncRNA expression in rhesus macaque (Macaca mulatta) brain in four representative age groups. We identified 18 anatomically diverse lncRNA modules and 14 mRNA modules representing spatial, age, and sex specificities. Spatiotemporal- and sex-biased changes in lncRNA expression were generally higher than those observed in mRNA expression. A negative correlation between lncRNA and mRNA expression in cerebral cortex was observed and functionally validated. Our findings offer a fresh insight into spatial-, age-, and sex-biased changes in lncRNA expression in macaque brain and suggest that the changes represent a previously unappreciated regulatory system that potentially contributes to brain development and aging.

Mechanism of long noncoding RNAs as transcriptional regulators in cancer.

Dysregulation of gene expression, often interpreted by gene transcription as an endpoint response, is tightly associated with human cancer. Long noncoding RNAs (lncRNAs), derived from the noncoding elements in the genome and appeared no less than 200nt in length, have emerged as a novel class of pivotal regulatory component. Recently, great attention has been paid to the cancer-related lncRNAs and growing evidence have shown that lncRNAs act as key transcriptional regulators in cancer cells through diverse mechanisms. Here, we focus on the nucleus-expressed lncRNAs and summarize their molecular mechanisms in transcriptional control during tumorigenesis and cancer metastasis. Six major mechanisms will be discussed in this review: association with transcriptional factor, modulating DNA methylation or histone modification enzyme, influencing on chromatin remodelling complex, facilitating chromosomal looping, interaction with RNA polymerase and direct association with promoter.

Downregulation of LINC00894-002 Contributes to Tamoxifen Resistance by Enhancing the TGF-ß Signaling Pathway.

Tamoxifen is a widely used personalized medicine for estrogen receptor (ER)-positive breast cancer, but approximately 30% of patients receiving the treatment relapse due to tamoxifen resistance (TamR). Recently, several reports have linked lncRNAs to cancer drug resistance. However, the role of lncRNAs in TamR is unclear. To identify TamR-related lncRNAs, we first used a bioinformatic approach to predict whether they have connection with known TamR-associated genes by starBase v2.0 and divided them into two groups. Group A contains lncRNAs that connect with known TamR genes and group B contains lncRNAs that show no predicted interaction. Among the 12 lncRNAs in group A, 58.3% of them are either up- or downregulated in MCF-7/TamR cells compared to the sensitive cells. In contrast, the expression levels of all group B lncRNAs are not changed in MCF-7/TamR cells. LINC00894-002 exhibits the most sophisticated network pattern and is the most downregulated lncRNA in MCF-7/TamR cells. Moreover, we find that LINC00894-002 is directly upregulated by ERα. Knocking down LINC00894-002 downregulates expression of miR-200a-3p and miR-200b-3p, upregulates the expression of TGF-ß2 and ZEB1, and finally contributes to TamR. Herein, we report the first case of an inhibitory lncRNA against TamR through the miR-200-TGF-ß2-ZEB1 signaling pathway.

[Effect of Huayu Jiedu Recipe on the Expressions of NLRP3, Caspasel, and IL-1 ß in Kidneys of Obstructive Nephropathy Rats].

Objective To observe the effect of Huayu Jiedu Recipe (HJR) on the expressions of nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) , Caspase-1 , IL-1 ß in kidneys of obstructive nephropathy rats. Methods Totally 40 clean grade SD rats were randomly divided into the sham-operation group (n =10) and the model group (n =30). The model of obstructive nephropa- thy was established by unilateral ureteral obstruction (UUO). Totally 30 successfully modeled UUO rats were randomly divided into the model group, the Western medicine group, the Chinese medicine group, 10 in each group. Eplerenone (100 mg . kg ⁻¹ . d⁻¹) was administrated to rats in the Western medicine group. HJR (13.7 g . kg ⁻¹ . d⁻¹) was administrated to rats in the Chinese medicine group. Equal volume of normal saline was administered to rats in the sham-operation group and the model group. All medica- tion was performed once daily for 10 successive days. The serum IL-1 ß level was detected. Protein and mRNA expressions of NLRP3, Caspase-1, and IL-1 ß in renal tissue were detected. TUNEL positive rate was detected by TUNEL method. Results The expression of NLRP3 was not obviously seen, Caspase-1 and IL-1 ß were weakly expressed, and only fewer amount of TUNEL positive cells could be seen in the sham-operation group. Compared with the sham-operation group, serum IL-1ß level increased (P < 0. 01) , mRNA and protein expression of NLRP3, Caspase-1 , and IL-1 ß were up-regulated in renal tissue of the model group (P <0. 01). NLRP3 was mainly expressed in renal interstitial macrophages and renal tubular epithelial cells. Caspase-1 and IL-1 ß were mainly expressed in the cytoplasm of renal tubular epithelial cells. TUNEL positive cells were significantly increased, mainly dominated in interstitial expanded epithelial cells of distal tubules (P <0. 01). Compared with the model group, serum IL-1 ß level was significantly decreased (P <0. 01) ; mRNA and protein expressions of NLRP3, Caspase-1 , and IL- ß were obviously down-regulated (P <0. 01) , and the TUNEL positive rate was obviously decreased (P <0. 05, P < 0. 01) in the two medicated groups. Conclusion HJR could down-regulate mRNA and protein expres- sions of NLRP3, Caspase-1 , and IL-1ß, thus attenuating inflammatory injury of renal tissue.

Tyrosine dephosphorylation of H2AX modulates apoptosis and survival decisions.

Life and death fate decisions allow cells to avoid massive apoptotic death in response to genotoxic stress. Although the regulatory mechanisms and signalling pathways controlling DNA repair and apoptosis are well characterized, the precise molecular strategies that determine the ultimate choice of DNA repair and survival or apoptotic cell death remain incompletely understood. Here we report that a protein tyrosine phosphatase, EYA, is involved in promoting efficient DNA repair rather than apoptosis in response to genotoxic stress in mammalian embryonic kidney cells by executing a damage-signal-dependent dephosphorylation of an H2AX carboxy-terminal tyrosine phosphate (Y142). This post-translational modification determines the relative recruitment of either DNA repair or pro-apoptotic factors to the tail of serine phosphorylated histone H2AX (gamma-H2AX) and allows it to function as an active determinant of repair/survival versus apoptotic responses to DNA damage, revealing an additional phosphorylation-dependent mechanism that modulates survival/apoptotic decisions during mammalian organogenesis.

Induced ncRNAs allosterically modify RNA-binding proteins in cis to inhibit transcription.

With the recent recognition of non-coding RNAs (ncRNAs) flanking many genes, a central issue is to obtain a full understanding of their potential roles in regulated gene transcription programmes, possibly through different mechanisms. Here we show that an RNA-binding protein, TLS (for translocated in liposarcoma), serves as a key transcriptional regulatory sensor of DNA damage signals that, on the basis of its allosteric modulation by RNA, specifically binds to and inhibits CREB-binding protein (CBP) and p300 histone acetyltransferase activities on a repressed gene target, cyclin D1 (CCND1) in human cell lines. Recruitment of TLS to the CCND1 promoter to cause gene-specific repression is directed by single-stranded, low-copy-number ncRNA transcripts tethered to the 5' regulatory regions of CCND1 that are induced in response to DNA damage signals. Our data suggest that signal-induced ncRNAs localized to regulatory regions of transcription units can act cooperatively as selective ligands, recruiting and modulating the activities of distinct classes of RNA-binding co-regulators in response to specific signals, providing an unexpected ncRNA/RNA-binding protein-based strategy to integrate transcriptional programmes.

Transcriptome and metabolome analyses provide insights into the fruit softening disorder of papaya fruit under postharvest heat stress.

Heat stress in summer causes softening disorder in papaya but the molecular mechanism is not clear. In this study, papaya fruit stored at 35 °C showed a softening disorder termed rubbery texture. Analysis of the transcriptome and metabolome identified numerous differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) between the fruit stored at 25 °C and 35 °C. The DEGs and DAMs related to lignin biosynthesis were upregulated, while those related to ethylene biosynthesis, sucrose metabolism, and cell wall degradation were downregulated under heat stress. Co-expression network analysis highlighted the correlation between the DEGs and metabolites associated with lignin biosynthesis, ethylene biosynthesis, and cell wall degradation under heat stress. Finally, the correlation analysis identified the key factors regulating softening disorder under heat stress. The study's findings reveal that heat stress inhibited papaya cell wall degradation and ethylene production, delaying fruit ripening and softening and ultimately resulting in a rubbery texture.

The role of PI3K/Akt signaling pathway in chronic kidney disease.

Chronic kidney disease (CKD), including chronic glomerulonephritis, IgA nephropathy and diabetic nephropathy, are common chronic diseases characterized by structural damage and functional decline of the kidneys. The current treatment of CKD is symptom relief. Several studies have reported that the phosphatidylinositol 3 kinases (PI3K)/protein kinase B (Akt) signaling pathway is a pathway closely related to the pathological process of CKD. It can ameliorate kidney damage by inhibiting this signal pathway which is involved with inflammation, oxidative stress, cell apoptosis, epithelial mesenchymal transformation (EMT) and autophagy. This review highlights the role of activating or inhibiting the PI3K/Akt signaling pathway in CKD-induced inflammatory response, apoptosis, autophagy and EMT. We also summarize the latest evidence on treating CKD by targeting the PI3K/Akt pathway, discuss the shortcomings and deficiencies of PI3K/Akt research in the field of CKD, and identify potential challenges in developing these clinical therapeutic CKD strategies, and provide appropriate solutions.

Losartan ameliorates renal fibrosis by inhibiting tumor necrosis factor signal pathway.

Losartan is widely used in the treatment of chronic kidney disease (CKD) and has achieved good clinical efficacy, but its exact mechanism is not clear. We performed high-throughput sequencing (HTS) technology to screen the potential target of losartan in treating CKD. According to the HTS results, we found that the tumor necrosis factor (TNF) signal pathway was enriched. Therefore, we conducted in vivo and in vitro experiments to verify it. We found that TNF signal pathway was activated in both unilateral ureteral obstruction (UUO) rats and human proximal renal tubular epithelial cells (HK-2) treated with transforming growth factor-ß1 (TGF-ß1), while losartan can significantly inhibit TNF signal pathway as well as the expression of fibrosis related genes (such as COL-1, α-SMA and Vimentin). These data suggest that losartan may ameliorate renal fibrosis through modulating the TNF pathway.

The roles of orphan nuclear receptor 4 group A1 and A2 in fibrosis.

Fibrosis is not a disease but rather an outcome of the pathological tissue repair response. Many myofibroblasts are activated which lead to the excessive accumulation of extracellular matrix components such as collagen and fibronectin with fibrosis. A variety of organs, including kidney, liver, lung, heart and skin, can undergo fibrosis under the stimulation of exogenous or endogenous pathogenic factors. The orphan nuclear receptor 4 group A1 (NR4A1) and nuclear receptor 4 group A2（NR4A2）are belong to the nuclear receptor subfamily and inhibit the occurrence and development of fibrosis. NR4A1 is an inhibitory factor of TGF-ß signaling transduction. Overexpression of NR4A1 in fibroblasts can reduce TGF-ß induced collagen deposition and fibrosis related gene expression. Here, we summarize the current research progress on the NR4A1/2 and fibrosis, providing reference for the treatment of fibrosis.