Increases in expression of carbohydrate sulfotransferases CHST11 and CHST15 and decline in N-acetylgalactosamine-4-sulfatase (Arylsulfatase B, ARSB) require phospho-p38-MAPK following exposure to SARS-CoV-2 spike protein receptor binding domain in human a

Objective: Immunohistochemistry of post-mortem lung tissue from Covid-19 patients with diffuse alveolar damage demonstrated marked increases in chondroitin sulfate and CHST15 and decline in N-acetylgalactosamine-4-sulfatase. Studies were undertaken to identify the mechanisms involved in these effects. Method(s): Human primary small airway epithelial cells (PCS 301-010;ATCC) were cultured and exposed to the SARSCoV- 2 spike protein receptor binding domain (SPRBD;AA: Lys310-Leu560;Amsbio). Expression of the spike protein receptor, angiotensin converting enzyme 2 (ACE2), was enhanced by treatment with Interferon-beta. Promoter activation, DNA-binding, RNA silencing, QPCR, Western blots, ELISAs, and specific enzyme inhibitors were used to elucidate the underlying molecular mechanisms. Result(s): Treatment of the cultured cells by the SPRBD led to increased CHST15 and CHST11 expression and decline in ARSB expression. Sulfotransferase activity, total chondroitin sulfate, and sulfated glycosaminoglycan (GAG) content were increased. Phospho-T180/T182-p38-MAPK and phospho- S423/S425-Smad3 were required for the activation of the CHST15 and CHST11 promoters. Inhibition by SB203580, a phospho-p38 MAPK inhibitor, and by SIS3, a Smad3 inhibitor, blocked the CHST15 and CHST11 promoter activation. SB203580 reversed the SPRBD-induced decline in ARSB expression, but SIS3 had no effect on ARSB expression or promoter activation. Phospho-p38 MAPK was shown to reduce retinoblastoma protein (RB) S807/S811 phosphorylation and increase RB S249/T252 phosphorylation. E2F-DNA binding declined following exposure to SPRBD, and SB203580 reversed this effect. This indicates a mechanism by which SPRBD, phospho-p38 MAPK, E2F, and RB can regulate ARSB expression and thereby impact on chondroitin 4-sulfate and dermatan sulfate and molecules that bind to these sulfated GAGs, including Interleukin-8, bone morphogenetic protein-4, galectin-3 and SHP-2 (Src homology region 2-containing protein tyrosine phosphatase 2). Conclusion(s): The enzyme ARSB is required for the degradation of chondroitin 4-sulfate and dermatan sulfate, and accumulation of these sulfated GAGs can contribute to lung pathophysiology, as evident in Covid-19. Some effects of the SPRBD may be attributable to unopposed Angiotensin II, when Ang1-7 counter effects are diminished due to binding of ACE2 with the SARS-CoV-2 spike protein and reduced production of Ang1-7. Aberrant cell signaling and activation of the phospho-p38 MAPK and Smad3 pathways increase CHST15 and CHST11 production, which can contribute to increased chondroitin sulfate in infected cells. Decline in ARSB may occur as a consequence of effects of phospho-p38 MAPK on RB phosphorylation and E2F1 availability. Decline in ARSB and the resulting impaired degradation of sulfated GAGs have profound consequences on cellular metabolic, signaling, and transcriptional events. Funding is VA Merit Award.Copyright © 2023 The American Society for Biochemistry and Molecular Biology, Inc.

Surfactant Protein B Reduces Respiratory Viral Infectivity in Human Lungs

Purpose of Study: COVID pneumonia caused by SARS-CoV-2 can result in a depletion of surfactant & lung injury, which resembles neonatal respiratory distress syndrome. Exogenous surfactant has shown promise as a therapeutic option in intubated hospitalized patients. Our preliminary data in human lung organoids (LOs) with a deficiency of surfactant protein B (SP-B) showed an increased viral load compared to normal LOs. Single cell RNA sequencing (scRNAseq) revealed that SP-B-deficient cells showed increased viral entry genes (ACE2 receptor) & dysregulated inflammatory markers emanating from the lung cells themselves. Our objective was to determine: (1) cell-specific transcriptional differences between normal & SP-B deficient human lung cells after infection with SARS-CoV-2 and (2) a therapeutic role of SP-B protein & surfactant in COVID-19 pneumonia. Methods Used: We used normal and SP-B mutant (homozygous, frameshift, loss of function mutation p.Pro133GlnfsTer95, previously known as 121ins2) human induced pluripotent stem cells (hiPSC) and differentiated them into 3D proximal lung organoids. The organoids were infected with the delta variant of SARS-CoV-2 for 24 hours at an MOI of 1. Infected and uninfected organoids were fixed in trizol in triplicate and underwent processing for bulk RNA sequencing. We tested for differentially expressed genes using the program DEseq. We also plated normal iPSC derived lung organoids as a monolayer and pre-treated them with 1mg/ml of Poractant alfa or 5 uM of recombinant SP-B protein. The delta strain of SARS-CoV-2 was added to the 96 wells at an MOI of 0.1 for one hour with shaking, then an overlay with DMEM/CMC/FBS was added and left on for 23 hours. The plate was fixed and stained for nucleocapsid (NC) protein. Summary of Results: Bioinformatic analysis of the bulk RNA sequencing data showed an increase in the multiple cytokines and chemokines in the SP-B mutant LOs compared to control. We also saw differential gene expression patterns in the SP-B mutant LOs including a reduction in SFTPC, FOXA2, and NKX2-1 and an increase in IL1A, VEGFA, PPARG and SMAD3. In the exogenous surfactant experiments, there was a decrease in total expression of viral NC in the Poractant alfa & rSP-B-treated cells compared to SARS-CoV-2 infection alone (p<0.001). Conclusion(s): Surfactant modulates the viral load of SARS-CoV-2 infection in the human lung. Deficiency in SP-B results in the dysregulation of the lung epithelial inflammatory signaling pathways resulting in worsening infections.

A review of fibroblast-like synoviocytes in the pathogenesis of Rheumatoid arthritis: Their activation and the inhibition of their apoptosis

Rheumatoid Arthritis (RA) is a systemic, autoimmune, inflammatory disease characterized by synovial hyperplasia, inflammatory cell infiltration in the synovial tissues, and progressive destruction of cartilage and bones. This disease often leads to chronic disability. More recently, activation of synovial fibroblasts (SFs) has been linked to innate immune responses and several cellular signalingpathways that ultimately result in the aggressive and invasive stages of RA. SFs are the major sources of pro-inflammatory cytokines in RA synovium. They participate in maintaining the inflammatory state that leads to synovial hyperplasia and angiogenesis in the inflamed synovium. The altered apoptotic response of synovial and inflammatory cells has been connected to these alterations of inflamed synovium. RA synovial fibroblasts (RASFs) have the ability to inhibit several apoptotic proteins that cause their abnormal proliferation. This proliferation leads to synovial hyperplasia. Apoptotic pathway proteins have thus been identified as possible targets for modifying the pathophysiology of RA. This review summarizes current knowledge of SF activation and its roles in the inhibition of apoptosis in the synovium, which is involved in joint damage during the effector phase of RA development.Copyright © 2022 Biomedpress.

Quercetin potentially suppresses renal fibrosis in patients with COVID-19 under hypoxic state

Introduction: Renal fibrosis is a main outcome of acute kidney injury in COVID-19 survivors, which is emerging as a global public health concern. Lung damage in the COVID-19 patients leads to acute and chronic hypoxia, which results in inflammation, epithelial-mesenchymal transformation, and fibrosis in kidney. Quercetin is an abundant flavonoid in plant materials. Previous studies indicate that quercetin alleviates the decline of renal function, suppress epithelial to mesenchymal transformation in renal tubules, and reduce fibrosis. The study aimed to explore potential targets of quercetin on treating renal fibrosis in patients with COVID-19-induced hoxpia. Method(s): Gene/protein targets related to COVID-19, renal fibrosis, or quercetin were searched from ten databases, and Cytoscape 3.8.2 was then used to construct the protein-protein interaction network and to identify the core targets. The Metascape platform was used for bioconcentration analysis, while AutoDock Vina was used as the primary molecular docking tool. In vitro, the combination model of hypoxia- and transforming growth factor-beta (TGF-beta)- treated human proximal tubule epithelial cells (HK2 cells) was applied to determine the reno-protective effect of quercetin. Result(s): The network analysis showed that quercetin targeted on TGF-beta pathway in treating COVID-19 induced renal fibrosis. In the intersection PPI network, 115 targets were obtained, and gene enrichment analysis was conducted on 109 key nodes. Molecular docking analysis revealed that quercetin could spontaneously bind to eight targets on the TGF-beta pathway, and the binding energy of TGF-beta1 was 29.82 kJ/mol. The in vitro experiment further showed that quercetin significantly suppressed fibrosis in TGF-beta and hypoxia treated HK2 cells in a dose dependent manner by inhibiting TGF-beta/Smad3 pathway. Conclusion(s): Quercetin could attenuate renal fibrosis in patients with COVID-19 by suppressing TGF-beta/Smad3 pathway. No conflict of interestCopyright © 2023

Rationale for evaluation of PLN-74809 treatment in participants with primary sclerosing cholangitis in Phase 2a study INTEGRIS-PSC

Background and aims: Transforming growth factor beta (TGF-beta) signalling is a key driver of liver fibrosis. In primary sclerosing cholangitis (PSC), integrins over-expressed on injured cholangiocytes (alpha-v/beta-6) and myofibroblasts (alpha-v/beta-1) regulate TGFbeta activity. PLN-74809 is an oral, once-daily, dual-selective inhibitor of integrins alpha-v/beta-6 and alpha-v/beta-1 in development for the treatment of PSC and idiopathic pulmonary fibrosis. It has shown favourable tolerability in over 280 healthy participants, reduced TGF-beta signalling and achieved high target engagement in human lungs. Pre-clinical evaluation of antifibrotic activity resulting from dual integrin inhibition was performed to support clinical evaluation. Method: PLN-74809 was administered orally for 6 weeks in BALBc. Mdr2-/- mice with established fibrosis. A tool alpha-v/beta-6 and alpha-v/beta-1 inhibitor compound, PLN-75068, was tested therapeutically in a diet-induced mouse model of biliary fibrosis using 3, 5-diethoxycarbonyl-1, 4-dihydrocollidine (DDC). Hepatic collagen was quantified by hydroxyproline (OHP) and collagen proportionate area (CPA) and TGF-beta signalling by phosphorylated SMAD3 (pSMAD3) levels. An ex vivo study evaluated the effects of 2-day treatment with PLN-74809 on the expression of profibrotic genes, COL1A1 and COL1A2, in precision-cut liver slices (PCLivS) from tissue explants of participants with biliary fibrosis (n = 2 PSC;n = 2 primary biliary cholangitis [PBC]). A review of available blinded safety data from the enrolling Phase 2a study in participants with PSC was performed (NCT04480840). Results: PLN-74809 dose-dependently reduced OHP (up to ∼30%, p < 0.05), CPA (up to ∼50%, p < 0.05) and pSMAD3 (up to ∼40%, p < 0.001) in the BALBc.Mdr2-/- mouse model, as well as COL1A1 and COL1A2 gene expression (up to ∼30%, p = 0.0789) in PCLivS from tissue explants of participants with PSC and PBC. PLN-75068 reduced OHP (up to ∼20%, p < 0.05) in DDC-injured mice in a dose-dependent manner. PLN-74809waswell tolerated in participants with PSC. Most adverse events (AEs)were mild;nonewere severe. The most common AE was mild headache. One participant experienced serious AEs at least 20 days after the last dose of study drug, deemed not related by the investigator. One participant prematurely discontinued due to COVID-19. PLN-74809 pharmacokinetics in participants with PSC were consistent with those of healthy participants. Conclusion: Pharmacological inhibition of integrins alpha-v/beta-6 and alpha-v/beta-1 demonstrated antifibrotic activity in two models of biliary fibrosis and in PCLivS from participants with PSC or PBC. Available safety findings from participants with PSC enrolled in the ongoing Phase 2a INTEGRIS-PSC study, continue to support the favourable tolerability profile of PLN-74809.

MANAGEMENT OF REFRACTORY SYMPTOMATIC PREMATURE VENTRICULAR CONTRACTIONS IN A PATIENT WITH LOUIS-DIETZ SYNDROME TYPE 3, EHLERS-DANLOS SYNDROME, AND SYSTEMIC LUPUS ERYTHEMATOSUS

Background: Louis-Dietz syndrome (LDS) Type 3 is a rare disorder caused by an autosomal-dominant mutation in SMAD-3, altering the TGF-β pathway. LDS Type 3 typically manifests as aortic aneurysms and early-onset osteoarthritis, however other dermatologic, cardiovascular, and skeletal abnormalities have been reported. Case: A 51-year-old woman was referred to the cardiology clinic for episodes of palpitations, syncope, chest pain, and shortness of breath during the COVID-19 pandemic. She had a history of congestive heart failure, cardiomyopathy, patent foramen ovale, atrial septal aneurysm, pre-COVID myocarditis, mitral valve prolapse, mitral regurgitation, and pericarditis. She also has a pertinent medical history of hypermobile Ehlers-Danlos syndrome (hEDS) and systemic lupus erythematosus (SLE). Her family and social history were remarkable for a daughter with SLE. Cardiopulmonary and general physical exams were remarkable for hypermobility. Evaluation with an ECG and Holter monitor showed normal sinus rhythm with unifocal premature ventricular contractions (PVCs) that correlated with her symptoms. Decision-making: The patient was initially managed un-successfully with beta and calcium channel blockers. Cardiac ablation was subsequently performed on a left ventricular septal focus with remote magnetic navigation using the Niobe system from Stereotaxis inc. (due to its low risk for cardiac perforation). At 6 months follow up, the patient exhibited an increase in left ventricular ejection fraction from 40-50% to 55-60%, fewer symptoms, and fewer PVCs. She was later diagnosed with a right internal carotid artery aneurysm that prompted genetic testing that was positive for LDS Type 3. Conclusion: This patient’s unique combination of illnesses required a multidisciplinary team for management. The Stereotaxis robotic system safely and successfully treated the patient’s PVCs and resulted in improvement of left ventricular function. Due to previous reports of arrhythmias associated with these connective tissue disorders, additional studies are necessary to understand the role of the SMAD-3 mutation, EDS, and SLE in contributing to arrhythmogenicity.