RNA sequence analysis reveals pathways and candidate genes associated with liver injury in a rat pancreatitis model

Assessing the causal link between liver function and acute pancreatitis: A Mendelian randomisation study

A correlation has been reported to exist between exposure factors (e.g. liver function) and acute pancreatitis. However, the specific causal relationship remains unclear. This study aimed to infer the causal relationship between liver function and acute pancreatitis using the Mendelian randomisation method. We employed summary data from a genome-wide association study involving individuals of European ancestry from the UK Biobank and FinnGen. Single-nucleotide polymorphisms (SCNPs), closely associated with liver function, served as instrumental variables. We used five regression models for causality assessment: MR-Egger regression, the random-effect inverse variance weighting method (IVW), the weighted median method (WME), the weighted model, and the simple model. We assessed the heterogeneity of the SNPs using Cochran's Q test. Multi-effect analysis was performed using the intercept term of the MR-Egger method and leave-one-out detection. Odds ratios (ORs) were used to evaluate the causal relationship between liver function and acute pancreatitis risk. A total of 641 SNPs were incorporated as instrumental variables. The MR-IVW method indicated a causal effect of gamma-glutamyltransferase (GGT) on acute pancreatitis (OR = 1.180, 95%CI [confidence interval]: 1.021-1.365, P = 0.025), suggesting that GGT may influence the incidence of acute pancreatitis. Conversely, the results for alkaline phosphatase (ALP) (OR = 0.997, 95%CI: 0.992-1.002, P = 0.197) and aspartate aminotransferase (AST) (OR = 0.939, 95%CI: 0.794-1.111, P = 0.464) did not show a causal effect on acute pancreatitis. Additionally, neither the intercept term nor the zero difference in the MR-Egger regression attained statistical significance (P = 0.257), and there were no observable gene effects. This study suggests that GGT levels are a potential risk factor for acute pancreatitis and may increase the associated risk. In contrast, ALP and AST levels did not affect the risk of acute pancreatitis.

Nonalcoholic fatty liver disease aggravates acute pancreatitis through bacterial translocation and cholesterol metabolic dysregulation in the liver and pancreas in mice

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is an independent risk factor for severe acute pancreatitis (AP). The underlying mechanism remains unclear. We sought to determine how bacterial translocation and cholesterol metabolism in the liver and pancreas affect the severity of AP in NAFLD mice.

METHODS

C57BL/6N mice were fed on a high-fat diet (HFD) to generate the NAFLD model, and mice in the control group were provided with a normal diet (ND). After being anesthetized with ketamine/xylazine, mice got a retrograde infusion of taurocholic acid sodium into the pancreatic duct to induce AP, and sham operation (SO) was used as control. Serum amylase and Schmidt's pathological score system were used to evaluate AP severity. Bacterial loads, total cholesterol level, and cholesterol metabolic-associated molecules [low-density lipoprotein receptor (LDLR) and ATP-binding cassette transporter A1 (ABCA1)] were analyzed in the liver and pancreas.

RESULTS

Compared with the ND-AP group, mice in the HFD-AP group had severer pancreatitis, manifested with higher serum amylase levels and higher AP pathologic scores, especially the inflammation and hemorrhage scores. Compared with the HFD-SO group and ND-AP group, bacterial loads in the liver and pancreas were significantly higher in the HFD-AP group. Mice in the HFD-AP group showed a decreased LDLR expression and an increased ABCA1 expression in the pancreas, although there was no significant difference in pancreas total cholesterol between the HFD-AP group and the ND-AP group.

CONCLUSIONS

NAFLD aggravates AP via increasing bacterial translocation in the liver and pancreas and affecting pancreas cholesterol metabolism in mice.

RNA sequencing and metabolic analysis of imiquimod-induced psoriasis-like mice with chronic restrain stress

AIM

Psoriasis is one of the most common dermatological disorders, characterized by increased epidermal hyperplasia and immune cell infiltration. Psychological stress has been reported to contribute to the severity, aggravation, and relapse of psoriasis. However, the exact mechanism involved in psychological stress's impact on psoriasis is still unclear. We aim to investigate the role of psychological stress in psoriasis from a transcriptomic and metabolomic perspective.

MAIN METHOD

We developed a chronic restrain stress (CRS)-imiquimod (IMQ)-induced psoriasis-like mouse model and performed a comprehensive comparative transcriptomic and metabolic analysis with control mice, CRS-treated mice, and IMQ-treated mice to investigate how psychological stress affects psoriasis.

KEY FINDING

We found that CRS-IMQ-induced psoriasis-like mice showed significant exacerbation of psoriasis-like skin inflammation compared with mice treated with IMQ only. Mice of the CRS + IMQ group showed increased expression of keratinocyte proliferation and differentiation genes, differential regulation of cytokines, and promotion of linoleic acid metabolism. Correlation analysis of differentially expressed genes in the CRS-IMQ-induced psoriasis-like mice and human psoriasis datasets compared with respective controls revealed 96 overlapping genes of which 30 genes showed consistent induced or repressed expression in all human and mouse datasets.

SIGNIFICANCE

Our study provides new insights into the effects of psychological stress on psoriasis pathogenesis and the mechanisms involved, which provides clues for development of therapeutics or biomarkers.

RNA sequencing and integrative analysis reveal pathways and hub genes associated with TGFβ1 stimulation on prostatic stromal cells

Objective: Benign prostatic hyperplasia (BPH) is the most common urological disease in elderly men. The transforming growth factor beta 1 (TGFβ1) plays an important role in the proliferation and differentiation of BPH stroma. However, it is not clear yet which important pathways and key genes are the downstream of TGFβ1 acting on prostatic stromal cells.

Methods: GSE132714 is currently the newer, available, and best high-throughput sequencing data set for BPH disease and includes the largest number of BPH cases. We examined the TGFβ1 expression level in BPH and normal prostate (NP) by analyzing the GSE132714 data set as well as carrying out immunohistochemistry of 15 BPH and 15 NP samples. Primary prostatic stromal cells (PrSCs) were isolated from five fresh BPH tissues. RNA sequencing and bioinformatics analysis were used to reveal important pathways and hub genes associated with TGFβ1 stimulation on PrSCs.

Results: TGFβ1 was upregulated in BPH stroma compared to NP stroma. A total of 497 genes (244 upregulated and 253 downregulated) were differentially expressed in PrSCs with and without TGFβ1 stimulation. The Gene Ontology revealed that differentially expressed genes (DEGs) were mainly enriched in progesterone secretion, interleukin-7 receptor binding, and CSF1-CSF1R complex. The Wnt signaling pathway, PI3K−Akt signaling pathway, JAK−STAT signaling pathway, and Hippo signaling pathway were screened based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. FN1, SMAD3, CXCL12, VCAM1, and ICAM1 were selected as hub genes according to the degree of connection from the protein–protein interaction (PPI) network.

Conclusion: This study sheds some new insights into the role of TGFβ1 in BPH stroma and provides some clues for the identification of potential downstream mechanisms and targets.

Liver injury associated with acute pancreatitis: The current status of clinical evaluation and involved mechanisms

Acute pancreatitis (AP) is a very common acute disease, and the mortality rate of severe AP (SAP) is between 15% and 35%. The main causes of death are multiple organ dysfunction syndrome and infections. The mortality rate of patients with SAP related to liver failure is as high as 83%, and approximately 5% of the SAP patients have fulminant liver failure. Liver function is closely related to the progression and prognosis of AP. In this review, we aim to elaborate on the clinical manifestations and mechanism of liver injury in patients with AP.

Proteomic analysis of early phosphorylated proteins in acute pancreatitis model

Background and Objective:

The exact mechanism of acute pancreatitis (AP), which is an inflammation of the pancreas, still remains unclear. In this study, we examined the protein phosphorylation changes during the early stage of AP in mice using proteomic analysis.

Methods:

AP model in mice was constructed using an intraperitoneal injection of cerulein. Blood samples and pancreas were collected at 1, 3, 6, 9h after the final injection (n=3 at each time point). Samples collected 3h after the final injection were separately mixed and named S (saline group) and C1 (cerulein group); samples collected 6h after the final injection from the cerulein group were mixed and named C2. Proteins from S, C1, and C2 were extracted, digested by trypsin, and subjected to LC-MS/MS analysis, bioinformatics analysis, and Western blotting.

Results:

A total of 549 sites (426 proteins) were upregulated, and 501 sites (367 proteins) were downregulated in C1 compared to S; while 491 phosphorylation sites (377 proteins) were upregulated and 367 sites (274 proteins) were downregulated in C2 compared to S. Motif analysis showed that proline-directed kinase and basophilic kinase had a key role during early AP. During an early AP stage, the cellular distributions of proteins slightly changed. The types of domains changed with the development of AP. Phosphorylation proteins associated with calcium signaling, especially IP3R mediated calcium release, lysosome and autophagosome pathway, pancreatic digestive activation, and secretion, were found to be involved in the development of early AP independent of NF-kB activation. Moreover, the MAPK family was found to have a greater impact at the early stage of AP. We also found differentially expressed phosphorylations of amylase and trypsinogen and increased phosphorylation of MAPK6 S189 in early AP.

Conclusion:

IP3R mediated calcium release and activation of MAPK family are key events promoting the development of early AP.

Dapagliflozin Reduces Urinary Albumin Excretion by Downregulating the Expression of cAMP, MAPK, and cGMP-PKG Signaling Pathways Associated Genes

Objective: Diabetic nephropathy (DN), the most severe complication of diabetes mellitus, is characterized by albuminuria and progressive loss of kidney function. Dapagliflozin (DAP), a sodium-glucose cotransporter inhibitor, is an oral medication that improves blood glucose control in diabetic patients. However, the effects and mechanisms of DAP on DN remain unclear. Materials and Methods: The effect of DAP was based on a retrospective cohort study of patients who underwent 2-year surveillance, and the concentration of urine albumin-to-creatinine ratio, glomerular filtration rate, and serum creatinine were collected after treatment with DAP. To investigate the underlying mechanisms through which DAP reduces urinary albumin excretion, we used RNA-sequencing (RNA-seq) to analyze gene expression in human kidney 2 (HK-2) cells treated with DAP. Results: The retrospective cohort analysis indicated that DAP could reduce the excretion rate of urinary albumin in patients with type 2 diabetes and renal impairment. The results of the RNA-seq experiments showed 349 differentially expressed genes between DAP-treated HK-2 cells and control cells. Gene ontology annotation enrichment analysis showed that DAP mainly affected the expression of integral component of membrane- and cell junction-related genes, while the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed that DAP primarily downregulated the expression of gene clusters associated with cyclic adenosine monophosphate, mitogen-activated protein kinase, and cyclic guanosine monophosphate-protein kinase G signaling pathways, which play critical roles in the progression of DN. Conclusion: Our results shed light on the mechanism by which DAP controls DN progression and provide a theoretical basis for the clinical treatment of DN.

AICAR, an AMP-Activated Protein Kinase Activator, Ameliorates Acute Pancreatitis-Associated Liver Injury Partially Through Nrf2-Mediated Antioxidant Effects and Inhibition of NLRP3 Inflammasome Activation

Acute pancreatitis (AP) is a highly fatal acute inflammation and is often accompanied by multiple organ dysfunction syndrome (MODS). The liver, one of the most vulnerable extrapancreatic organs in AP, is the major organ involved in the evolution of the disease and correlates strongly with the occurrence of MODS. However, the etiology of pancreatitis-associated liver injury (PALI) has not been clarified and currently lacks an effective treatment. 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR) is a cell permeable nucleoside with pleiotropic effects on anti-inflammatory and antioxidant stress that binds with adenosine monophosphate protein kinase (AMPK) and induces AMPK activation. However, the role of AICAR in PALI remains elusive. Here, we show that activation of AMPK by AICAR, a direct AMPK agonist, significantly ameliorates sodium taurocholate-induced PALI in rats, whereas treatment of PALI rats with the AMPK antagonist Compound C profoundly exacerbates the degree of liver injury, suggesting that hepatic AMPK activation exerts an essential protective role in PALI. Mechanistically, AICAR induces AMPK activation, which in turn activates nuclear factor erythroid 2-related factor 2(Nrf2) -regulated hepatic antioxidant capacity and inhibits NLRP3 inflammasome-mediated pyrolysis, protecting rats from sodium taurocholate-induced PALI. In addition, Nrf2 deficiency strikingly weakens the beneficial effects of AICAR on alleviation of liver injury, oxidative stress and NLRP3 inflammasome activation in L-arginine-induced PALI mice. Thus, AICAR protects against PALI in rodents by triggering AMPK, which is mediated at least in part by Nrf2-modulated antioxidant effects and NLRP3 inflammasome activation.

L-Theanine Alleviates IMQ-Induced Psoriasis Like Skin Inflammation by Downregulating the Production of IL-23 and Chemokines

Psoriasis, the most common skin inflammatory disease, is characterized by massive keratinocyte proliferation and immune cell infiltration into epidermis. L-Theanine (L-THE), a nonproteinogenic amino acid derived from green tea (Camellia sinensis), has been proved to possess the properties of anti-inflammatory, antidepressants and neuroprotective. However, whether L-THE has a therapeutic effect on psoriasis is still unknown. In this study, we found that the epidermal thickness and inflammatory response were significantly reduced in Imiquimod (IMQ)-induced psoriasis mice by applying with L-THE on mice skin. The expression of proliferation and inflammation associated genes such as keratin 17, IL-23 and CXCL1-3 was also downregulated by L-THE. Furthermore, L-THE inhibited the production of IL-23 in dendritic cells (DCs) after IMQ treatment, and decreased the levels of chemokines in keratinocytes treated with IL-17A by downregulating the expression of IL-17RA. RNA-seq and KEGG analysis revealed that L-THE significantly regulated the expression of IL-17A and NF-κB signaling pathway-associated genes. Metabolomics analysis displayed that L-THE promoted propanoate metabolism which has been reported to inhibit the activity of TH17 cells. Therefore, our results demonstrated that L-THE significantly decreases the levels of IL-23 and chemokines, and attenuates IMQ-induced psoriasis like skin inflammation by inhibiting the activation of NF-κB and IL-17A signaling pathways, and promoting the propanoate metabolism. Our findings suggest that topical applied L-THE can be used as a topical drug candidate for the treatment of psoriasis or as an adjuvant treatment of ustekinumab or secukinumab to prevent the relapse of psoriasis.

HPV11E7 inhibits IMQ-induced chemokine and colony-stimulating factor production in keratinocytes

Imiquimod (IMQ) is approved as a first-line treatment for genital warts caused by human papillomavirus (HPV) infection. However, the recurrence rate is very high. HPV E7 protein plays a critical role in HPV immune escape. However, the role of HPV11 E7 protein in genital warts recurrence during IMQ treatment is not clear. Here, we found that the expression profile of NHEK cells was obviously changed after IMQ treatment, and a large number of genes encoding cytokines and genes involved in cytokine-mediated signaling pathways and cellular metabolic signaling pathways were up- or downregulated. HPV11E7 overexpression inhibited the IMQ-induced production of of multiple chemokines and colony-stimulating factors in NHEK cells. Furthermore, we found that HPV11E7 could impair the activation of mitogen-activated protein kinase (MAPK) signaling pathway. Therefore, our results suggested that HPV11 E7 diminishes the production of chemokines, colony-stimulating factors and other cytokines via inhibition of the MAPK signaling pathway, which suppresses the therapeutic effect of IMQ and promotes the recurrence of diseases, such as condyloma acuminatum.

BTX-A Promotes Expression of Angiogenesis-Associated Genes in Human Umbilical Vein Endothelial Cells

Raynaud's phenomenon (RP) is an episodic vasospasm of the peripheral arteries caused by an exaggerated reaction to cold temperature or emotional stress. Restoring the angiogenesis capability of the acral lesional skin is a critical strategy to treat RP. Local injection of botulinum toxin-A (BTX-A) has also been reported for treatment of RP. However, since the exact mechanisms of BTX-A action are still unclear, its administration for treatment of RP is not widely used. In the present study, BTX-A was found to promote angiogenesis and relieve RP in the patient. To elucidate its mechanisms against angiogenesis, BTX-A was used to treat human umbilical vein endothelial cells (HUVECs), one of the most popular in vitro models of angiogenesis, and RNA sequencing was used to investigate differentially expressed genes. A total of 413 genes were upregulated, and 1634 were downregulated, with fold-changes >2.0 in HUVECs treated with BTX-A. Gene ontology annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed BTX-A affected expression of angiogenesis-associated, angiogenesis-associated signaling pathway-related, metabolic pathway, and epigenetic regulation-related genes. These results demonstrate potential biomarkers of BTX-A action, thereby providing potential therapeutic mechanism(s) by which BTX-A relieves RP symptoms.