Fine mapping and candidate gene analysis of a major QTL for oil content in the seed of Brassica napus.

KEY MESSAGE: By integrating QTL fine mapping and transcriptomics, a candidate gene responsible for oil content in rapeseed was identified. The gene is anticipated to primarily function in photosynthesis and photosystem metabolism pathways. Brassica napus is one of the most important oil crops in the world, and enhancing seed oil content is an important goal in its genetic improvement. However, the underlying genetic basis for the important trait remains poorly understood in this crop. We previously identified a major locus, OILA5 responsible for seed oil content on chromosome A5 through genome-wide association study. To better understand the genetics of the QTL, we performed fine mapping of OILA5 with a double haploid population and a BC3F2 segregation population consisting of 6227 individuals. We narrowed down the QTL to an approximate 43 kb region with twelve annotated genes, flanked by markers ZDM389 and ZDM337. To unveil the potential candidate gene responsible for OILA5, we integrated fine mapping data with transcriptome profiling using high and low oil content near-isogenic lines. Among the candidate genes, BnaA05G0439400ZS was identified with high expression levels in both seed and silique tissues. This gene exhibited homology with AT3G09840 in Arabidopsis that was annotated as cell division cycle 48. We designed a site-specific marker based on resequencing data and confirmed its effectiveness in both natural and segregating populations. Our comprehensive results provide valuable genetic information not only enhancing our understanding of the genetic control of seed oil content but also novel germplasm for advancing high seed oil content breeding in B. napus and other oil crops.

The correlation between serum uric acid and diabetic kidney disease in adult-onset type 1 diabetes patients in China.

BACKGROUND/AIM: To assess the correlation between serum uric acid (UA) level and diabetic kidney disease among adult-onset Type 1 diabetes mellitus (T1DM) patients in China. METHODS: A total of 184 patients with adult-onset T1DM between January 2014 and December 2016 were recruited, with demographics and medical data collected. Comparisons were performed between according to different serum UA gender-specific quartiles. Relationship between serum UA level with urinary ACR and eGFR was also assessed. RESULTS: Median urinary ACR and eGFR were 21.55 [10.79, 45.02] mg/g and 113.86 [88.43, 143.61] ml/min/1.73 m2, respectively. The median UA was 257.4 (208.2-334.8) µmol/L. Participants with higher serum UA levels had higher urinary ACR and lower eGFR than those with lower UA (P < 0.05). Higher serum UA level was significantly associated with higher urinary ACR in Spearman's correlational analysis (P = 0.006) and multiple stepwise regression analysis (P = 0.013). The association between serum UA and urinary ACR was not linear, but showed a curve correlation, which also showed in the sensitivity analysis. Serum UA in the upper gender-specific quartile, was associated with lower eGFR (P < 0.001) and showed an independent negative correlation with eGFR in multiple stepwise regression analysis (P < 0.001). CONCLUSIONS: The serum UA level was negatively correlated with eGFR and had a curve correlation with urinary ACR in adult-onset T1DM patients of China.

Related factors of crescents and prognosis in IgA nephropathy.

BACKGROUND: IgA nephropathy (IgAN) has the highest prevalence among primary glomerular diseases worldwide, and crescent is a risk predictor of renal prognosis in IgAN. However, this is still controversial, and more research is needed to further confirm the importance of crescents in IgAN patients. So we aim to investigate the related factors and prognosis of IgAN with crescents. MATERIALS AND METHODS: 178 patients diagnosed with IgAN by renal biopsy were selected into a crescent group (C group, C1: 0% < crescent proportion < 25%, C2: crescent proportion ≥ 25%) and a non-crescent group (C0 group). The clinical and renal pathology indexes were compared, and the progression of proteinuria and renal function were followed up. RESULTS: Compared with the C0 group, the C group revealed lower level of serum albumin, hemoglobin, serum C3, and IgA complements, higher level of 24-hour urine protein quantity and urine erythrocyte count. Statistical differences in the degree of mesangial hyperplasia and C3 complement deposition were found between the two groups. Logistic regression analysis showed that hemoglobin and C3 complement deposition (+ and + +) were independent related factors of crescents in IgAN. Cumulative renal survival rate in C2 was significantly lower than in C1 (χ2 = 5.532, p = 0.019). IgAN patients with more crescents (≥ 25%) (adjusted hazard ratio (AHR) = 4.905, 95% CI: 1.135 - 21.208, p = 0.0033) and platelets (AHR = 1.016, CI: 1.006 - 1.023, p = 0.001) were more likely to progress to the end event in Cox regression analysis. CONCLUSION: IgAN patients with crescents may have severe clinical symptoms and poor prognosis. The crescents and serum platelet count are risk predictors of poor prognosis in IgAN.

TRPA1 protects mice from pathogenic Citrobacter rodentium infection via maintaining the colonic epithelial barrier function.

Transient receptor potential ankyrin 1 (TRPA1) is expressed in gastrointestinal tract and plays important roles in intestinal motility and visceral hypersensitivity. However, the potential role of TRPA1 in host defense, particularly against intestinal pathogens, is unknown. Here, we show that Trpa1 knockout mice exhibited increased susceptibility to Citrobacter rodentium infection, associated with the increased severity of diarrhea and intestinal permeability associated with the disrupted tight junctions (TJs) in colonic epithelia. We further demonstrated the expression of TRPA1 in murine colonic epithelial cells (CECs) and human epithelial Caco-2 cells both at protein level and transcription level. Using calcium imaging, TRPA1 agonists allyl isothiocyanates (AITC) and hydrogen peroxide were observed to induce a transient Ca2+ response in Caco-2 cells, respectively. Moreover, TRPA1 knockdown in Caco-2 cells resulted in the decreased expression of TJ proteins, ZO-1 and Occludin, and in the increased paracellular permeabilities and the reduced TEER values of Caco-2 monolayers in vitro. Furthermore, inhibition of TRPA1 by HC-030031 in the confluent Caco-2 cells caused the altered distribution and expression of TJ proteins, ZO-1, Occludin, and Claudin-3, and exacerbated the bacterial endotoxin lipopolysaccharide (LPS)-induced damage to these TJ proteins and actin cytoskeleton. By contrast, AITC pretreatment restored the distribution and expression of these TJ proteins in the confluent Caco-2 cells upon LPS challenge. Our results identify an unrecognized protective role of TRPA1 in host defense against an enteric bacterial pathogen by maintaining colonic epithelium barrier function, at least in part, via preserving the distribution and expression of TJ proteins in CECs.

A case of membranous nephropathy with Kimura's disease.

BACKGROUND: The association between membranous nephropathy (MN) and Kimura's disease (KD) has been reported in recent years. The treatment, effect, and prognosis of KD are still unclear. CASE REPORT: A 47-year-old KD patient developed a left axillary mass for 3 years and received surgical resection because of the lager mass in August 2016. Then he developed nephrotic syndrome 3 months later. Laboratory index revealed increased eosinophil count, decreased albumin and heavy proteinuria. Lymph node biopsy suggested KD, and renal biopsy suggested MN. He relapsed after a treatment with methylprednisolone (52 mg/d) alone and then tacrolimus (1.5 mg/12h) was added. The patient had no symptoms of relapse in the next 2 years. CONCLUSION: The combination therapy of surgery, methylprednisolone, and immunosuppressive agents may be effective in KD with MN.

Serum iron and risk of nonalcoholic fatty liver disease and advanced hepatic fibrosis in US adults.

Epidemiological evidence on the relationship between serum iron and liver diseases is limited. This study aims to investigate whether serum iron is associated with nonalcoholic fatty liver disease (NAFLD) and advanced hepatic fibrosis (AHF). Cross-sectional data for adults aged ≥ 18 years who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018 were analyzed. Odds ratio (ORs) and 95% confidence intervals (CIs) of NAFLD and AHF associated with serum iron were estimated using multivariable logistic regression models. A total of 18,031 males and 18,989 females were included in the analysis. After multivariable adjustment for potential confounders, serum iron was significantly and inversely associated with NAFLD in both genders (P-trend < 0.001) and AHF in females (P-trend = 0.018). Compared to the bottom quartile, those in higher quartiles of serum iron had no significant ORs for AHF in males, but the trend across the quartiles was significant (P-trend = 0.046). In conclusion, higher serum iron level was associated with lower risk of NAFLD in males and females, and with lower risk of AHF in females but not in males. No significant racial/ethnical differences in these associations were observed.

Worldwide burden of genital human papillomavirus infection in female sex workers: a systematic review and meta-analysis.

BACKGROUND: Although female sex workers (FSWs) have long been identified as a key human papillomavirus (HPV)-affected population, the burden and scope of their disproportionate risk for HPV infection have not been systematically estimated. We therefore aimed to estimate the prevalence of HPV and the distribution of HPV types in FSWs at the country, regional and global levels. METHODS: We searched the PubMed, Embase, SCOPUS, EBSCO, ProQuest, Cochrane Library and Web of Science databases for articles published between 1 January 1990 and 31 June 2019. Studies of genital HPV prevalence in FSWs, or with sufficient data (e.g. adequate number of HPV-positive cases and sample size) to compute prevalence rates in FSWs, were included in this systematic review. The meta-analysis was completed using the random effects model. RESULTS: We ultimately identified 107 studies in 45 countries or regions with sufficient data to calculate HPV prevalence in FSWs. The pooled global HPV prevalence among FSWs was 39.5% (95% CI 35.3, 43.9%), with notable variations by WHO region and country. Globally, the five most common HPV types in FSWs were HPV16 (9.0%), HPV 52 (8.3%), HPV89 (7.0%), HPV58 (6.2%), and HPV53 (5.3%). CONCLUSIONS: Our findings suggest that FSWs are disproportionately affected by HPV, which is more pronounced in the Western Pacific and African regions, and are therefore in need of prevention, treatment and care services.

Effect of Tai Chi Chuan in Breast Cancer Patients: A Systematic Review and Meta-Analysis.

Background: Tai Chi Chuan(TCC), as a mind-body exercise, may have a positive impact on physical function and psychological well-being in breast cancer patients. The latest systematic review and meta-analysis of TCC for breast cancer was made 4 years ago and some new clinical trials about it were published. We remade a systematic review and meta-analysis to evaluate the effect of TCC in breast cancer patients. Methods: In this systematic review and meta-analysis, we searched MEDLINE (via PubMed), EMBASE (via embase.com), CENTRAL, CNKI, COVIP, Wanfang, Chaoxing, CiNii, J-SSTAGE, DBpia, and ThaiJO with no language restrictions from inception to December 31, 2018 (updated on February 16, 2020), for randomized clinical trials comparing TCC with non-exercised therapy in breast cancer patients. The primary outcome was quality of life in patients with breast cancer and data pooled by a random-effects model. Subgroup analyses were conducted to estimate the effect of different durations of TCC for breast cancer patients. This study was registered in PROSPERO, number CRD 4201810326. Results: Fifteen articles involving a total of 885 breast cancer participants were included in this review. Compared with non-exercised therapy, TCC had a significant effect on quality of life in breast cancer patients (SMD = 0.37, 95% CI 0.15-0.59, p = 0.001), and subgroup analysis found that TCC showed beneficial effect in 12 weeks and 25 weeks (12 weeks: SMD = 0.40, 95% CI 0.19-0.62, p = 0.0003; 25 weeks: SMD = 0.38, 95% CI 0.15-0.62, p = 0.002). Meta-analyses of secondary outcomes showed that 3 weeks TCC increased shoulder function (SMD = 1.08, 95% CI 0.28-1.87, p = 0.008), 12 weeks TCC improved pain (SMD = 0.30, 95% CI 0.08-0.51, p = 0.007), shoulder function (SMD = 1.34, 95% CI 0.43-2.25, p = 0.004), strength of arm (SMD = 0.44, 95% CI 0.20-0.68, p = 0.0004), and anxiety (MD = -4.90, 95% CI -7.83 to -1.98, p = 0.001) in breast cancer patients compared with the control group. Conclusions: TCC appears to be effective on some physical and psychological symptoms and improves the quality of life in patients with breast cancer. Additional randomized controlled trials with a rigorous methodology and low risk of bias are needed to provide more reliable evidence.

An fMRI-based neural marker for migraine without aura.

OBJECTIVE: To identify and validate an fMRI-based neural marker for migraine without aura (MwoA) and to examine its association with treatment response. METHODS: We conducted cross-sectional studies with resting-state fMRI data from 230 participants and machine learning analyses. In studies 1 through 3, we identified, cross-validated, independently validated, and cross-sectionally validated an fMRI-based neural marker for MwoA. In study 4, we assessed the relationship between the neural marker and treatment responses in migraineurs who received a 4-week real or sham acupuncture treatment, or were waitlisted, in a registered clinical trial. RESULTS: In study 1 (n = 116), we identified a neural marker with abnormal functional connectivity within the visual, default mode, sensorimotor, and frontal-parietal networks that could discriminate migraineurs from healthy controls (HCs) with 93% sensitivity and 89% specificity. In study 2 (n = 38), we investigated the generalizability of the marker by applying it to an independent cohort of migraineurs and HCs and achieved 84% sensitivity and specificity. In study 3 (n = 76), we verified the specificity of the marker with new datasets of migraineurs and patients with other chronic pain disorders (chronic low back pain and fibromyalgia) and demonstrated 78% sensitivity and 76% specificity for discriminating migraineurs from nonmigraineurs. In study 4 (n = 116), we found that the changes in the marker responses showed significant correlation with the changes in headache frequency in response to real acupuncture. CONCLUSION: We identified an fMRI-based neural marker that captures distinct characteristics of MwoA and can link disease pattern changes to brain changes.

Weighted correlation network analysis of triple-negative breast cancer progression: Identifying specific modules and hub genes based on the GEO and TCGA database.

Triple-negative breast cancer (TNBC) represents an aggressive malignancy of frequent high histologic grade with no effective specific targeted therapies. The present study aimed to identify specific modules and hub genes that may influence the progression of TNBC. The key words 'breast cancer' were used to search microarray datasets in the Gene Expression Omnibus and The Cancer Genome Atlas databases that included 5 datasets. A total of 11 co-expression modules were constructed based on the expression levels of 5,782 genes obtained from 456 patients with TNBC using the weighted correlation network analysis (WGCNA). The results demonstrated that the red module was significantly associated with relapse-free survival (RFS) in patients with TNBC [hazard ratio (HR)=0.381, 95% confidence interval (CI), 0.183-0.793; P=0.010]. The functional enrichment analysis revealed that the biological processes corresponding to the red module were 'mRNA processing', 'histone lysine methylation' and 'regulation of TOR signaling'. In addition, Hedgehog signaling pathways were considered to serve a critical role in the development of this disease (P<0.001). A total of 12 hub genes were identified, of which α-thalassemia/mental retardation syndrome X-linked (ATRX) was significantly associated with RFS in patients with TNBC (HR=0.601; 95%CI, 0.376-0.960; P=0.033). The receiver operating characteristic curve indicated that ATRX could distinguish relapse from non-relapse in patients with TNBC (area under the curve=0.570; P=0.023). In conclusion, the present study demonstrated that ATRX was associated with TNBC progression, which suggested that ATRX may be involved in a recombination-mediated telomere maintenance mechanism.

Expression and localization of MrgprD in mouse intestinal tract.

MrgprD, a Mas-related G protein-coupled receptor, is initially identified in sensory neurons of mouse dorsal root ganglia (DRG) and has been suggested to participate in somatosensation. However, MrgprD has recently been found to be expressed outside the nervous system such as in aortic endothelia cells and neutrophils. In this study, we used immunohistochemistry to detect the expression and localization of MrgprD in mouse intestinal tract. The immunoreactivity (IR) of MrgprD was found in the smooth muscle layers of small intestine, colon and rectum. In addition, MrgprD IR was colocalized with F4/80-positive macrophages and CD3-positive T lymphocytes resident in the lamina propria of intestinal mucosa. MrgprD was also found to be expressed in primary peritoneal macrophages and splenic T lymphocytes. Furthermore, the presence of MrgprD mRNA and its protein was detected in murine macrophage-like RAW 264.7 and human T lymphocyte Jurkat cell lines. Our study shows, for the first time, the expression and localization of MrgprD in the intestinal tract and in macrophages and T lymphocytes, indicating the potential roles of MrgprD in intestinal mobility and immunity.

Facilitation of MrgprD by TRP-A1 promotes neuropathic pain.

Neuropathic pain remains a therapeutic challenge because of its complicated mechanisms. Mas-related GPCR D (MrgprD) is specifically expressed in small-diameter, nociceptive neurons of dorsal root ganglia (DRGs) and is implicated in pain modulation. However, the underlying mechanism of MrgprD involved in neuropathic pain remains elusive. In this study, we used behavioral experiments and physiologic examination methods to investigate the role of MrgprD in chronic constriction injury (CCI)-induced neuropathic pain. We found that MrgprD is necessary for the initiation of mechanical hypersensitivity and cold allodynia, but not for heat allodynia. Moreover, we demonstrated that transient receptor potential cation channel (TRP)-A1 was the ion channel downstream of MrgprD, and the ß-alanine-induced calcium signal was attributed mostly to TRP-A1 function. We further showed that PKA serves as a downstream mediator of ß-alanine-activated MrgprD signaling to activate TRP-A1 in DRG neurons and in human embryonic kidney 293 cells, to coexpress MrgprD and TRP-A1 plasmids. Finally, we found that the ß-alanine-induced pain behavior was increased, whereas the itching behavior was unchanged in CCI models compared with sham-injured animals. Knockout of TRPA1 also attenuated the ß-alanine-induced pain behavior in CCI models. In conclusion, MrgprD is essential in cold allodynia in CCI-induced neuropathic pain through the PKA-TRP-A1 pathway. TRP-A1 facilitates MrgprD to development of neuropathic pain. Our findings reveal a novel mechanism of neuropathic pain formation and highlight MrgprD as a promising drug target for the treatment of neuropathic pain.-Wang, C., Gu, L., Ruan, Y., Geng, X., Xu, M., Yang, N., Yu, L., Jiang, Y., Zhu, C., Yang, Y., Zhou, Y., Guan, X., Luo, W., Liu, Q., Dong, X., Yu, G., Lan, L., Tang, Z. Facilitation of MrgprD by TRP-A1 promotes neuropathic pain.

Prognostic value of IL-6R mRNA in lung adenocarcinoma and squamous cell carcinoma.

Previous studies have demonstrated that the interleukin (IL)-6/ IL-6 receptor (IL-6R) signaling pathway contributes to the pathogenesis of lung cancer. Lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) are the two major pathological subtypes of non-small cell lung cancer (NSCLC). The present study aimed to elucidate the potential clinical prognosis and biological function of IL-6R mRNA expression in LUAD and LUSC. The search term 'lung cancer' was used to search through the Gene Expression Omnibus database. Including LUAD and LUSC datasets in The Cancer Genome Atlas database, a total of 8 LUAD and 6 LUSC datasets were included in the present analysis. It was observed that a higher expression level of IL-6R mRNA in tumor tissues was a significant positive prognostic factor for overall survival in LUAD [pooled hazard ratio (HR), 0.48 and P<0.001 for univariate analysis; pooled HR, 0.50 and P<0.001 for multivariate analysis] while there was no similar association in LUSC (pooled HR, 1.59 and P=0.062 for univariate analysis; pooled HR, 1.58 and P=0.079 for multivariate analysis). Correlation analysis revealed that IL-6 and IL-6R were negatively correlated in LUAD and positively correlated in LUSC. IL-6R and its most correlated genes were primarily involved in cell cycle progression in LUAD and primarily involved in tumor angiogenesis, invasion and metastasis in LUSC. These results suggest a possible role of tumoral expression for IL-6R in LUAD, which means it may have potential as a prognostic marker for this type of cancer.

EGFR-TKI-induced HSP70 degradation and BER suppression facilitate the occurrence of the EGFR T790 M resistant mutation in lung cancer cells.

Non-small cell lung cancer (NSCLC) patients harboring EGFR-activating mutations initially respond to EGFR tyrosine kinase inhibitors (EGFR-TKIs) and have shown favorable outcomes. However, acquired drug resistance to EGFR-TKIs develops in almost all patients mainly due to the EGFR T790 M mutation. Here, we show that treatment with low-dose EGFR-TKI results in the emergence of the EGFR T790 M mutation and in the reduction of HSP70 protein levels in HCC827 cells. Erlotinib treatment inhibits HSP70 phosphorylation at tyrosine 41 and increases HSP70 ubiquitination, resulting in HSP70 degradation. We show that EGFR-TKI treatment causes increased DNA damage and enhanced gene mutation rates, which are secondary to the EGFR-TKI-induced reduction of HSP70 protein. Importantly, HSP70 overexpression delays the occurrence of Erlotinib-induced EGFR T790 M mutation. We further demonstrate that HSP70 interacts with multiple enzymes in the base excision repair (BER) pathway and promotes not only the efficiency but also the fidelity of BER. Collectively, our findings show that EGFR-TKI treatment facilitates gene mutation and the emergence of EGFR T790 M secondary mutation by the attenuation of BER via induction of HSP70 protein degradation.

MrgprA3 shows sensitization to chloroquine in an acetone-ether-water mice model.

Chronic itch, a distressing symptom of many cutaneous and systemic diseases, significantly impairs quality of life. However, its underlying molecular mechanism is still unclear. Mas-related G protein-coupled receptor A3 (MrgprA3) is considered an itch-specific receptor. MrgprA3 neurons are identified as a class of itch-specific neurons, but the role of MrgprA3 in chronic itch remains elusive. An acetone-ether-water (AEW) model as a histamine-independent itch model is often used in the study of chronic pruritus. In this study, behavioral tests, immunostaining, cell culture, calcium imaging, and other experiments were carried out to examine the expression of MrgprA3. The results showed that the scratching bouts induced by chloroquine increased significantly under the AEW condition; the density of MrgprA3 sensory fibers in the AEW-treated skin area and the number of MrgprA3 neurons in dorsal root ganglia from the AEW model mice also increased significantly. Further analysis showed that the MrgprA3 in mRNA level was also increased after AEW treatment. These results indicated that MrgprA3 played a crucial role in chronic pruritus in the AEW model.

High mRNA expression level of IL-6R was associated with better prognosis for patients with ovarian cancer: a pooled meta-analysis.

Interleukin-6 acts as both a pro-inflammatory cytokine and an anti-inflammatory myokine. IL-6/IL-6R signaling pathway, in particular, has been proposed to be a pivotal cytokine promoting ovarian cancer progression. This study aimed to elucidate potential clinical and biological function of IL-6R mRNA expression in ovarian cancer. We used the keywords "ovarian cancer" and searched through GEO database and finally a total of 7 studies together with TCGA database were incorporated in this analysis. We used Cutoff Finder to determine a cutoff point and stratified patients into two groups and found that high-expression of IL-6R mRNA in tumor tissues was a positive prognostic factor for overall survival. Simultaneously, high expression level of IL-6R mRNA correlates with better survival of patients who had additional chemotherapy treatment. These analyses suggested a possible role of tumoral expression of IL-6R in ovarian cancer. In conclusion, our results showed that mRNA levels of IL-6R in ovarian cancer was positively associated with better prognosis and sensitivity to chemotherapy and can potentially be used as a prognostic marker for this cancer.

Daphnetin reduces endotoxin lethality in mice and decreases LPS-induced inflammation in Raw264.7 cells via suppressing JAK/STATs activation and ROS production.

OBJECTIVE: Here, we used various approaches to investigate the suppressive role of daphnetin in LPS-induced inflammatory response, with the goal to understand the underlining molecular mechanism by which daphnetin regulated these processes. METHODS: We examined the survival rate and the lung injury in the mice model of LPS-induced endotoxemia. The production of pro-inflammatory factors including tumor necrosis factor α (TNF-α), interleukin-1ß (IL-1ß), IL-6, nitric oxide (NO), and prostaglandin E2 (PGE2) was measured by ELISA and nitrite analysis, respectively. The expression of inducible NO synthase (iNOS), cyclooxygenase 2 (COX-2), and the activation of signaling molecules was determined by immunoblotting. The production of reactive oxygen species (ROS) was measured by the ROS assay. RESULTS: In vivo study showed that daphnetin enhanced the survival rate and reduced the lung injury in mice with LPS-induced endotoxemia. Both in vivo and in vitro study showed that daphnetin prevented the production of pro-inflammatory factors including TNF-α, IL-1ß, IL-6, NO, and PGE2 after LPS challenge. In Raw264.7 cells, we found that daphnetin reduced LPS-induced expression of iNOS and COX-2, and suppressed LPS-induced ROS production. In addition, we found that daphnetin suppressed the activation of JAK/STATs pathway and inhibited the nucleus import of STAT1 and STAT3. CONCLUSIONS: Here, our results indicate that daphnetin shows anti-inflammatory properties, at least in part, through suppressing LPS-induced activation of JAK/STATs cascades and ROS production.

Phosphorylated heat shock protein 27 promotes lipid clearance in hepatic cells through interacting with STAT3 and activating autophagy.

Nonalcoholic fatty liver disease (NAFLD) has become the major liver disease worldwide. Recently, several studies have identified that the activation of autophagy attenuates hepatic steatosis. Heat shock protein 27 (Hsp27) is involved in autophagy in response to various stimuli. In this study, we demonstrate that phosphorylated Hsp27 stimulates autophagy and lipid droplet clearance and interacts with STAT3. In vivo study showed that high fat diet (HFD) feeding increased Hsp25 (mouse orthology of Hsp27) phosphorylation and autophagy in mouse livers. Inhibition of Hsp25 phosphorylation exacerbated HFD-induced hepatic steatosis in mice. In vitro study showed that palmitate-induced lipid overload in hepatic cells was enhanced by Hsp27 knockdown, KRIBB3 treatment and Hsp27-3A (non-phosphorylatable) overexpression but was prevented by Hsp27-WT (wild type) and Hsp27-3D (phosphomimetic) overexpression. Mechanism analysis demonstrated that palmitate could induce Hsp27 phosphorylation which promoted palmitate-induced autophagy. Phosphorylated Hsp27 interacted with STAT3 in response to palmitate treatment, and disrupted the STAT3/PKR complexes, facilitated PKR-dependent eIF2α phosphorylation, and thus stimulated autophagy. To conclude, our study provides a novel mechanism by which the phosphorylated Hsp27 promotes hepatic lipid clearance and suggests a new insight for therapy of steatotic diseases such as nonalcoholic fatty liver disease (NAFLD).

Glutathione S-transferase P1 suppresses iNOS protein stability in RAW264.7 macrophage-like cells after LPS stimulation.

Glutathione S-transferase P1 (GSTP1) is a ubiquitous expressed protein which plays an important role in the detoxification and xenobiotics metabolism. Previous studies showed that GSTP1 was upregulated by the LPS stimulation in RAW264.7 macrophage-like cells and GSTP1 overexpression downregulated lipopolysaccharide (LPS) induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. Here we show that GSTP1 physically associates with the oxygenase domain of iNOS by the G-site domain and decreases the protein level of iNOS dimer. Both overexpression and RNA interference (RNAi) experiments indicate that GSTP1 downregulates iNOS protein level and increases S-nitrosylation and ubiquitination of iNOS. The Y7F mutant type of GSTP1 physically associates with iNOS, but shows no effect on iNOS protein content, iNOS S-nitrosylation, and changes in iNOS from dimer to monomer, suggesting the importance of enzyme activity of GSTP1 in regulating iNOS S-nitrosylation and stability. GSTM1, another member of GSTs shows no significant effect on regulation of iNOS. In conclusion, our study reveals the novel role of GSTP1 in regulation of iNOS by affecting S-nitrosylation, dimerization, and stability, which provides a new insight for analyzing the regulation of iNOS and the anti-inflammatory effects of GSTP1.

Pirt contributes to uterine contraction-induced pain in mice.

Uterine contraction-induced pain (UCP) represents a common and severe form of visceral pain. Nerve fibers that innervate uterine tissue express the transient receptor potential vanilloid channel 1 (TRPV1), which has been shown to be involved in the perception of UCP. The phosphoinositide-interacting regulator of TRP (Pirt) may act as a regulatory subunit of TRPV1. The intraperitoneal injection of oxytocin into female mice after a 6-day priming treatment with estradiol benzoate induces writhing responses, which reflect the presence of UCP. Here, we first compared writhing response between Pirt (+/+) and Pirt (-/-) mice. Second, we examined the innervation of Pirt-expressing nerves in the uterus of Pirt (-/-) mice by immunofluorescence and two-photon microscopy. Third, we identified the soma of dorsal root ganglion (DRG) neurons that innerve the uterus using retrograde tracing and further characterized the neurochemical properties of these DRG neurons. Finally, we compared the calcium response of capsaicin between DRG neurons from Pirt (+/+) and Pirt (-/-) mice. We found that the writhing responses were less intensive in Pirt (-/-) mice than in Pirt (+/+) mice. We also observed Pirt-expressing nerve fibers in the myometrium of the uterus, and that retrograde-labeled cells were small-diameter, unmyelinated, and Pirt-positive DRG neurons. Additionally, we found that the number of capsaicin-responding neurons and the magnitude of evoked calcium response were markedly reduced in DRG neurons from Pirt (-/-) mice. Taken together, we speculate that Pirt plays an important role in mice uterine contraction-induced pain.