PGF2α signaling drives fibrotic remodeling and fibroblast population dynamics in mice.

Idiopathic pulmonary fibrosis (IPF) is a chronic parenchymal lung disease characterized by repetitive alveolar cell injury, myofibroblast proliferation, and excessive extracellular matrix deposition for which unmet need persists for effective therapeutics. The bioactive eicosanoid, prostaglandin F2α, and its cognate receptor FPr (Ptgfr) are implicated as a TGF-ß1-independent signaling hub for IPF. To assess this, we leveraged our published murine PF model (IER-SftpcI73T) expressing a disease-associated missense mutation in the surfactant protein C (Sftpc) gene. Tamoxifen-treated IER-SftpcI73T mice developed an early multiphasic alveolitis and transition to spontaneous fibrotic remodeling by 28 days. IER-SftpcI73T mice crossed to a Ptgfr-null (FPr-/-) line showed attenuated weight loss and gene dosage-dependent rescue of mortality compared with FPr+/+ cohorts. IER-SftpcI73T/FPr-/- mice also showed reductions in multiple fibrotic endpoints for which administration of nintedanib was not additive. Single-cell RNA-Seq, pseudotime analysis, and in vitro assays demonstrated Ptgfr expression predominantly within adventitial fibroblasts, which were reprogrammed to an "inflammatory/transitional" cell state in a PGF2α /FPr-dependent manner. Collectively, the findings provide evidence for a role for PGF2α signaling in IPF, mechanistically identify a susceptible fibroblast subpopulation, and establish a benchmark effect size for disruption of this pathway in mitigating fibrotic lung remodeling.

Disruption of Prostaglandin F2α Receptor Signaling Attenuates Fibrotic Remodeling and Alters Fibroblast Population Dynamics in A Preclinical Murine Model of Idiopathic Pulmonary Fibrosis.

Idiopathic Pulmonary Fibrosis (IPF) is a chronic parenchymal lung disease characterized by repetitive alveolar cell injury, myofibroblast proliferation, and excessive extracellular matrix deposition for which unmet need persists for effective therapeutics. The bioactive eicosanoid, prostaglandin F2α, and its cognate receptor FPr (Ptfgr) are implicated as a TGFß1 independent signaling hub for IPF. To assess this, we leveraged our published murine PF model (IER - SftpcI73T) expressing a disease-associated missense mutation in the surfactant protein C (Sftpc) gene. Tamoxifen treated IER-SftpcI73T mice develop an early multiphasic alveolitis and transition to spontaneous fibrotic remodeling by 28 days. IER-SftpcI73T mice crossed to a Ptgfr null (FPr-/-) line showed attenuated weight loss and gene dosage dependent rescue of mortality compared to FPr+/+ cohorts. IER-SftpcI73T/FPr-/- mice also showed reductions in multiple fibrotic endpoints for which administration of nintedanib was not additive. Single cell RNA sequencing, pseudotime analysis, and in vitro assays demonstrated Ptgfr expression predominantly within adventitial fibroblasts which were reprogrammed to an "inflammatory/transitional" cell state in a PGF2α/FPr dependent manner. Collectively, the findings provide evidence for a role for PGF2α signaling in IPF, mechanistically identify a susceptible fibroblast subpopulation, and establish a benchmark effect size for disruption of this pathway in mitigating fibrotic lung remodeling.

Ocular surface sphingolipids associate with the refractory nature of vernal keratoconjunctivitis: newer insights in VKC pathogenesis.

BACKGROUND: The etiopathogenesis of vernal keratoconjunctivitis (VKC) is incompletely understood. Bioactive lipids play a key role in allergic disorders. This study focused on the sphingolipid metabolism on the ocular surface of VKC and to explore if it has a contributory role in the refractoriness of the disease. METHODS: Active VKC cases, (n=87) (classified as mild/moderate and severe/very severe based on the disease symptoms) and age-matched healthy controls (n=60) were recruited as part of a 2-year prospective study at a tertiary eye care centre in South India. Conjunctival imprint cytology was used to assess gene expression of enzymes of sphingolipids metabolism. Sphingolipids were estimated in the tears by LC-MS/MS analysis. In vitro study was done to assess IgE-induced alterations in sphingosine-1-phosphate (S1P) receptor expression and histone modification in cultured mast cells. RESULTS: Significantly altered gene expression of the sphingolipids enzymes and S1P receptor (SIP3R) were observed in conjunctival imprint cells of VKC cases. Pooled tears analysis revealed significantly lowered levels of S1P(d17:0), S1P(d20:1) (p<0.001) and S1P(d17:1) (p<0.01) specifically in severe/very severe VKC compared with both mild/moderate VKC and control. Cer(d18:/17:0) (p<0.001), ceramide-1-phosphate (C1P)(d18:1/8:0) (p<0.01) and C1P(d18:1/2.0 (p<0.05) were lowered in severe/very severe VKC compared with mild/moderate VKC. Cultured mast cells treated with IgE revealed significantly increased gene expression of S1P1 and 3 receptors and the protein expression of histone deacetylases (1, 6). CONCLUSION: Altered sphingolipid metabolism in the ocular surface results in low tear ceramide and sphingosine levels in severe/very severe VKC compared with the mild/moderate cases. The novel finding opens up fresh targets for intervention in these refractory cases.

Single-dose oral ivermectin in mild and moderate COVID-19 (RIVET-COV): A single-centre randomized, placebo-controlled trial.

INTRODUCTION: Ivermectin is an antiparasitic drug which has in-vitro efficacy in reducing severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) viral load. Hence, Ivermectin is under investigation as a repurposed agent for treating COVID-19. METHODS: In this pilot, double blind, randomized controlled trial, hospitalized patients with mild-to-moderate COVID-19 were assigned to a single oral administration of an elixir formulation of Ivermectin at either 24 mg or 12 mg dose, or placebo in a 1:1:1 ratio. The co-primary outcomes were conversion of RT-PCR to negative result and the decline of viral load at day 5 of enrolment. Safety outcomes included total and serious adverse events. The primary outcomes were assessed in patients who had positive RT-PCR at enrolment (modified intention-to-treat population). Safety outcomes were assessed in all patients who received the intervention (intention-to-treat population). RESULTS: Among the 157 patients randomized, 125 were included in modified intention-to-treat analysis. 40 patients each were assigned to Ivermectin 24 mg and 12 mg, and 45 patients to placebo. The RT-PCR negativity at day 5 was higher in the two Ivermectin arms but failed to attain statistical significance (Ivermectin 24 mg, 47.5%; 12 mg arm, 35.0%; and placebo arm, 31.1%; p-value = 0.30). The decline of viral load at day 5 was similar in each arm. No serious adverse events occurred. CONCLUSIONS: In patients with mild and moderate COVID-19, a single oral administration of Ivermectin did not significantly increase either the negativity of RT-PCR or decline in viral load at day 5 of enrolment compared with placebo.

Hybridization of Fluoro-amodiaquine (FAQ) with Pyrimidines: Synthesis and Antimalarial Efficacy of FAQ-Pyrimidines.

To evade the possible toxicity associated with the formation of quinone-imine metabolite in amodiaquine (AQ), the para-hydroxyl group was replaced with a -F atom, and the resulting 4'-fluoro-amodiaquine (FAQ) was hybridized with substituted pyrimidines. The synthesized FAQ-pyrimidines displayed better in vitro potency than chloroquine (CQ) against the resistant P. falciparum strain (Dd2), exhibiting up to 47.3-fold better activity (IC50: 4.69 nM) than CQ (IC50: 222 nM) and 2.8-fold better potency than artesunate (IC50: 13.0 nM). Twelve compounds exhibited better antiplasmodial activity than CQ against the CQ-sensitive (NF54) strain. Two compounds were evaluated in vivo against a P. berghei-mouse malaria model. Mechanistic heme-binding studies, computational docking studies against Pf-DHFR and in vitro microsomal stability studies were performed for the representative molecules of the series to assess their antimalarial efficacy.

Molecular and Metabolic Markers of Fructose Induced Hepatic Insulin Resistance in Developing and Adult Rats are Distinct and Aegle marmelos is an Effective Modulator.

The time course of pathogenesis of fructose mediated hepatic insulin resistance (HepIR) is not well-delineated and we chronicle it here from post-weaning to adulthood stages. Weaned rats were provided for either 4 or 8 weeks, i.e., upto adolescence or adulthood, chow + drinking water, chow + fructose, 15% or chow + fructose, 15% + hydroalcoholic extract of leaves of Aegle marmelos (AM-HM, 500 mg/kg/d, po) and assessed for feed intake, fructose intake, body weight, fasting blood sugar, oral glucose tolerance test, HOMA-IR, insulin tolerance test and lipid profile. Activities of enzymes (glucose-6-phosphatase, hexokinase, phosphofructokinase, aldehyde dehydrogenase), hormones (leptin, ghrelin, insulin), insulin signaling molecules (Akt-PI3k, AMPK, JNK) hallmarks of inflammation (TNF-α), angiogenesis (VEGF), hypoxia (HIF-1), lipogenesis (mTOR) and regulatory nuclear transcription factors of de novo lipogenesis and hepatic insulin resistance gene (SREBP-1, FoxO1) that together govern the hepatic fructose metabolism, were also studied. The effect of fructose-rich environment on metabolic milieu of hepatocytes was confirmed using (human hepatocellular carcinoma) HepG2 cells. Using in vitro model, fructose uptake and glucose output from isolated murine hepatocytes were measured to establish the HepIR under fructose environment and delineate the effect of AM-HM. The leaves from the plant Aegle marmelos (L) Correa were extracted, fractionated and validated for rutin content using LC-MS/MS. The rutin content of extract was quantified and correlated with oral pharmacokinetic parameters in rat. The outcomes of the study suggest that the molecular and metabolic markers of fructose induced HepIR in developing and adult rats are distinct. Further, AM-HM exerts a multi-pronged attack by raising insulin secretion, augmenting insulin action, improving downstream signaling of insulin, reducing overall requirement of insulin and modulating hepatic expression of glucose transporter (Glut2). The butanol fraction of AM-HM holds promise for future development.