J Crohns Colitis. 2020 Aug 8:jjaa166. doi: 10.1093/ecco-jcc/jjaa166. Online ahead of print.

ABSTRACT

BACKGROUND AND AIMS: Ileal strictures are the major indication for resective surgery in Crohn's disease (CD). We aimed to define ileal gene programs present at diagnosis linked with future stricturing behavior during five year follow-up, and to identify potential small molecules to reverse these gene signatures.

METHODS: Antimicrobial serologies and pre-treatment ileal gene expression were assessed in a representative subset of 249 CD patients within the RISK multicenter pediatric CD inception cohort study, including 113 that are unique to this report. These data were used to define genes associated with stricturing behavior and for model testing to predict stricturing behavior. A bioinformatics approach to define small molecules which may reverse the stricturing gene signature was applied.

RESULTS: 19 of the 249 patients developed isolated B2 stricturing behavior during follow-up, while 218 remained B1 inflammatory. Using deeper RNA sequencing than in our prior report, we have now defined an inflammatory gene signature including an oncostatin M co-expression signature, tightly associated with extra-cellular matrix (ECM) gene expression in those who developed stricturing complications. We further computationally prioritize small molecules targeting macrophage and fibroblast activation and angiogenesis which may reverse the stricturing gene signature. A model containing ASCA and CBir1 serologies and a refined eight ECM gene set was significantly associated with stricturing development by year five after diagnosis (AUC (95th CI) = 0.82 (0.7-0.94)).

CONCLUSION: An ileal gene program for macrophage and fibroblast activation is linked to stricturing complications in treatment naïve pediatric CD, and may inform novel small molecule therapeutic approaches.

PMID:32770196 | DOI:10.1093/ecco-jcc/jjaa166

EMBO Mol Med. 2020 Sep 7;12(9):e12131. doi: 10.15252/emmm.202012131. Epub 2020 Aug 6.

ABSTRACT

Fibroblast activation including proliferation, survival, and ECM production is central to initiation and maintenance of fibrotic lesions in idiopathic pulmonary fibrosis (IPF). However, druggable molecules that target fibroblast activation remain limited. In this study, we show that multiple pro-fibrotic growth factors, including TGFα, CTGF, and IGF1, increase aurora kinase B (AURKB) expression and activity in fibroblasts. Mechanistically, we demonstrate that Wilms tumor 1 (WT1) is a key transcription factor that mediates TGFα-driven AURKB upregulation in fibroblasts. Importantly, we found that inhibition of AURKB expression or activity is sufficient to attenuate fibroblast activation. We show that fibrosis induced by TGFα is highly dependent on AURKB expression and treating TGFα mice with barasertib, an AURKB inhibitor, reverses fibroblast activation, and pulmonary fibrosis. Barasertib similarly attenuated fibrosis in the bleomycin model of pulmonary fibrosis. Together, our preclinical studies provide important proof-of-concept that demonstrate barasertib as a possible intervention therapy for IPF.

PMID:32761869 | PMC:PMC7507328 | DOI:10.15252/emmm.202012131

J Cyst Fibros. 2020 Sep;19(5):815-822. doi: 10.1016/j.jcf.2020.06.011. Epub 2020 Jun 25.

ABSTRACT

BACKGROUND: Cystic fibrosis (CF) patients develop severe lung disease including chronic airway infections, neutrophilic inflammation, and progressive fibrotic remodeling in airways. However, cellular and molecular processes that regulate excessive collagen deposition in airways in these patients remain unclear. Fibrocytes are bone marrow (BM)-derived mesenchymal cells that express the hematopoietic cell marker CD45, and mesenchymal cell markers and implicated in collagen deposition in several fibrotic diseases. It is unknown whether fibrocytes accumulate in the lungs of CF patients, so the current study evaluates the presence of fibrocytes in the fibrotic lesions of airways in explanted CF lungs compared to non-CF unused donor lungs (control).

METHODS: We used immunofluorescence staining to determine if fibrocytes accumulate in explanted CF lungs compared to healthy donor lungs. Simultaneously, we evaluated cells collected by bronchoalveolar lavage (BAL) in CF patients using multi-color flow cytometry. Finally, we analyzed transcripts differentially expressed in fibrocytes isolated from the explanted CF lungs compared to control to assess fibrocyte-specific pro-fibrotic gene networks.

RESULTS: Our findings demonstrate fibrocyte accumulation in CF lungs compared to non-CF lungs. Additionally, fibrocytes were detected in the BAL of all CF children. Transcriptomic analysis of fibrocytes identified dysregulated genes associated with fibrotic remodeling in CF lungs.

CONCLUSIONS: With significantly increased fibrocytes that show increased expression of pro-fibrotic gene transcripts compared to control, our findings suggest an intervention for fibrotic remodeling as a potential therapeutic target in CF.

PMID:32593509 | PMC:PMC7492481 | DOI:10.1016/j.jcf.2020.06.011

Lab Invest. 2020 Sep;100(9):1238-1251. doi: 10.1038/s41374-020-0433-4. Epub 2020 Apr 29.

ABSTRACT

The mechanisms which underlie defects in learning and memory are a major area of focus with the increasing incidence of Alzheimer's disease in the aging population. The complex genetically-controlled, age-, and environmentally-dependent onset and progression of the cognitive deficits and neuronal pathology call for better understanding of the fundamental biology of the nervous system function. In this study, we focus on nuclear receptor binding factor-2 (NRBF2) which modulates the transcriptional activities of retinoic acid receptor α and retinoid X receptor α, and the autophagic activities of the BECN1-VPS34 complex. Since both transcriptional regulation and autophagic function are important in supporting neuronal function, we hypothesized that NRBF2 deficiency may lead to cognitive deficits. To test this, we developed a new mouse model with nervous system-specific knockout of Nrbf2. In a series of behavioral assessment, we demonstrate that NRBF2 knockout in the nervous system results in profound learning and memory deficits. Interestingly, we did not find deficits in autophagic flux in primary neurons and the autophagy deficits were minimal in the brain. In contrast, RNAseq analyses have identified altered expression of genes that have been shown to impact neuronal function. The observation that NRBF2 is involved in learning and memory suggests a new mechanism regulating cognition involving the role of this protein in regulating networks related to the function of retinoic acid receptors, protein folding, and quality control.

PMID:32350405 | DOI:10.1038/s41374-020-0433-4

Cardiovasc Res. 2020 Mar 14:cvaa067. doi: 10.1093/cvr/cvaa067. Online ahead of print.

ABSTRACT

AIM: Cardiac dysfunction is a prevalent comorbidity of disrupted inflammatory homeostasis observed in conditions such as sepsis (acute) or obesity (chronic). Secreted and transmembrane protein 1a (Sectm1a) has previously been implicated to regulate inflammatory responses, yet its role in inflammation-associated cardiac dysfunction is virtually unknown.

METHODS AND RESULTS: Using the CRISPR/Cas9 system, we generated a global Sectm1a-knockout (KO) mouse model and observed significantly increased mortality and cardiac injury after LPS injection, when compared to wild-type (WT) control. Further analysis revealed significantly increased accumulation of inflammatory macrophages in hearts of LPS-treated KO mice. Accordingly, ablation of Sectm1a remarkably increased inflammatory cytokines levels both in vitro [from bone marrow-derived macrophages (BMDMs)] and in vivo (in serum and myocardium) after LPS challenge. RNA-sequencing results and bioinformatics analyses showed that the most significantly downregulated genes in KO-BMDMs were modulated by LXRα, a nuclear receptor with robust anti-inflammatory activity in macrophages. Indeed, we identified that the nuclear translocation of LXRα was disrupted in KO-BMDMs when treated with GW3965 (LXR agonist), resulting in higher levels of inflammatory cytokines, compared to GW3965-treated WT-cells. Furthermore, using chronic inflammation model of high-fat diet (HFD) feeding, we observed that infiltration of inflammatory monocytes/macrophages into KO-hearts were greatly increased and accordingly, worsened cardiac function, compared to WT-HFD controls.

CONCLUSION: This study defines Sectm1a as a new regulator of inflammatory-induced cardiac dysfunction through modulation of LXRα signaling in macrophages. Our data suggest that augmenting Sectm1a activity may be a potential therapeutic approach to resolve inflammation and associated cardiac dysfunction.

TRANSLATIONAL PERSPECTIVE: Better understanding on the interaction between inflammatory responses and cardiac health is prominent for the development of safer and more efficacious therapies for heart failure patients. The present study, using both acute (LPS) and chronic (high-fat diet) inflammation models, reiterated the adverse effects of abnormal macrophages activation on cardiac function. Our Sectm1a knockout mouse model showed exacerbated cardiac and systemic inflammatory responses, resulting in further aggravation of contractile dysfunction on the heart after endotoxin challenge. We also demonstrated Sectm1a as a new regulator of macrophage function through LXRα pathway. These data suggest a novel approach to regulate macrophage-elicited inflammation.

PMID:32170929 | DOI:10.1093/cvr/cvaa067

J Clin Anesth. 2020 Jun;62:109738. doi: 10.1016/j.jclinane.2020.109738. Epub 2020 Feb 12.

ABSTRACT

STUDY OBJECTIVE: To employ systems biology-based machine learning to identify biologic processes over-represented with genetic variants (gene enrichment) implicated in post-surgical pain.

DESIGN: Informed systems biology based integrative computational analyses.

SETTING: Pediatric research and teaching institution.

INTERVENTIONS: Pubmed search (01/01/2001-10/31/2017) was performed to identify "training" genes associated with postoperative pain in humans. Candidate genes were identified and prioritized using Toppgene suite, based on functional enrichment using several gene ontology annotations, and curated gene sets associated with mouse phenotype-knockout studies.

MEASUREMENTS: Computationally top-ranked candidate genes and literature-curated genes were included in pathway enrichment analyses. Hierarchical clustering was used to visualize select functional enrichment results between the two phenotypes.

MAIN RESULTS: Literature review identified 38 training genes associated with postoperative pain and 31 with CPSP. We identified 2610 prioritized novel candidate genes likely associated with acute and chronic postsurgical pain, the top 10th percentile jointly enriched (p 0.05; Benjamini-Hochberg correction) several pathways, topmost being cAMP response element-binding protein and ion channel pathways. Heat maps demonstrated enrichment of inflammatory/drug metabolism processes in acute postoperative pain and immune mechanisms in CPSP.

CONCLUSION: High interindividual variability in pain responses immediately after surgery and risk for CPSP suggests genetic susceptibility. Lack of large homogenous sample sizes have led to underpowered genetic association studies. Systems biology can be leveraged to integrate genetic-level data with biologic processes to generate prioritized candidate gene lists and understand novel biological pathways involved in acute postoperative pain and CPSP. Such data would be key to informing future polygenic studies with targeted genome wide profiling. This study demonstrates the utility of functional annotation - based prioritization and enrichment approaches and identifies novel genes and unique/shared biological processes involved in acute and chronic postoperative pain. Results provide framework for future targeted genetic profiling of CPSP risk, to enable preventive and therapeutic approaches.

PMID:32058259 | PMC:PMC7276001 | DOI:10.1016/j.jclinane.2020.109738

Redox Biol. 2020 May;32:101453. doi: 10.1016/j.redox.2020.101453. Epub 2020 Feb 6.

ABSTRACT

Currently, most antioxidants do not show any favorable clinical outcomes in reducing myocardial ischemia-reperfusion (I/R) injury, suggesting an urgent need for exploring a new regulator of redox homeostasis in I/R hearts. Here, using heart-specific transgenic (TG) and knockdown (KD) mouse models, tumor susceptibility gene 101 (Tsg101) is defined as a novel cardiac-protector against I/R-triggered oxidative stress. RNA sequencing and bioinformatics data surprisingly reveal that most upregulated genes in Tsg101-TG hearts are transcribed by Nrf2. Accordingly, pharmacological inhibition of Nrf2 offsets Tsg101-elicited cardio-protection. Mechanistically, Tsg101 interacts with SQSTM1/p62 through its PRR domain, and promotes p62 aggregation, leading to recruitment of Keap1 for degradation by autophagosomes and release of Nrf2 to the nucleus. Furthermore, knockout of p62 abrogates Tsg101-induced cardio-protective effects during I/R. Hence, our findings uncover a previously unrecognized role of Tsg101 in the regulation of p62/Keap1/Nrf2 signaling cascades and provide a new strategy for the treatment of ischemic heart disease.

PMID:32057709 | PMC:PMC7264471 | DOI:10.1016/j.redox.2020.101453