Elevated Alpha 1(I) to Alpha 2(I) Collagen Ratio in Dermal Fibroblasts Possibly Contributes to Fibrosis in Systemic Sclerosis

Systemic sclerosis (SSc) is characterized by excessive collagen deposition in the skin and internal organs. Activated fibroblasts are the key effector cells for the overproduction of type I collagen, which comprises the α1(I) and α2(I) chains encoded by COL1A1 and COL1A2, respectively. In this study, we examined the expression patterns of α1(I) and α2(I) collagen in SSc fibroblasts, as well as their co-regulation with each other. The relative expression ratio of COL1A1 to COL1A2 in SSc fibroblasts was significantly higher than that in control fibroblasts. The same result was observed for type I collagen protein levels, indicating that α2(I) collagen is more elevated than α2(I) collagen. Inhibition or overexpression of α1(I) collagen in control fibroblasts affected the α2(I) collagen levels, suggesting that α1(I) collagen might act as an upstream regulator of α2(I) collagen. The local injection of COL1A1 small interfering RNA in a bleomycin-induced SSc mouse model was found to attenuate skin fibrosis. Overall, our data indicate that α2(I) collagen is a potent regulator of type I collagen in SSc; further investigations of the overall regulatory mechanisms of type I collagen may help understand the aberrant collagen metabolism in SSc.     

A Human Cellular Model for Colorectal Anastomotic Repair: The Effect of Localization and Transforming Growth Factor-β1 Treatment on Collagen Deposition and Biomarkers

Anastomotic leakage (AL) is a devastating complication after colorectal surgery, possibly due to the loss of stabilizing collagen fibers in the submucosa. Our aim was to assess the formation of collagen in the colon versus the rectum with or without transforming growth factor (TGF)-β1 exposure in a human cellular model of colorectal repair. Primary fibroblasts were isolated by an explant procedure from clinically resected tissue rings during anastomosis construction in 19 consecutive colorectal patients who underwent laparoscopy. The cells, identified as fibroblasts by morphologic characteristics and flow cytometry analysis (CD90⁺), were cultured for 8 days and in 12 patients in the presence of 1 ng/mL TGF-β1. Total collagen deposition was measured colorimetrically after Sirius red staining of fixed cell layers, and type I, III, and VI collagen biosynthesis and degradation were specifically determined by the biomarkers PINP, PRO-C3, PRO-C6, and C3M in conditioned media by competitive enzyme-linked immunosorbent assays. Total collagen deposition by fibroblasts from the colon and rectum did not significantly differ. TGF-β1 treatment increased PINP, PRO-C6, and total collagen deposition. Mechanistically, TGF-β1 treatment increased COL1A1 and ACTA2 (encoding α-smooth muscle actin), and decreased COL6A1 and MMP2 mRNA levels in colorectal fibroblasts. In conclusion, we found no effect of anatomic localization on collagen production by fibroblasts derived from the large intestine. TGF-β1 represents a potential therapeutic agent for the prevention of AL by increasing type I collagen synthesis and collagen deposition.     

Role of the ROS-JNK Signaling Pathway in Hypoxia-Induced Atrial Fibrotic Responses in HL-1 Cardiomyocytes

By promoting atrial structural remodeling, atrial hypoxia contributes to the development of the atrial fibrillation substrate. Our study aimed to investigate the modulatory effect of hypoxia on profibrotic activity in cultured HL-1 cardiomyocytes and explore the possible signaling transduction mechanisms of profibrotic activity in vitro. Hypoxia (1% O₂) significantly and time-dependently increased the expression of hypoxia-inducible factor (HIF)-1α and fibrotic marker proteins collagen I and III (COL1A and COL3A), transforming growth factor (TGF)-β1 and α-smooth muscle actin (SMA). Western blot or immunohistochemistry analysis showed that hypoxia-induced increase in COL1A and COL3A was significantly attenuated by the addition of SP600125 (a specific c-Jun N-terminal kinase [JNK] inhibitor) or expression of dominant-negative JNK before hypoxia treatment. The inhibition of hypoxia-activated phosphorylation of JNK signal components (JNK, MKK4, nuclear c-Jun and ATF-2) by pre-treatment with SP600125 could suppress hypoxia-stimulated HIF-1α upregulation and fibrotic marker proteins expression. Hypoxia significantly increased reactive oxygen species (ROS) production in cultured HL-1 atrial cells. Pre-treatment with N-acetylcysteine significantly abrogated the expression of nuclear HIF-1α, JNK transduction components and fibrotic marker proteins. Taken together, these findings indicated that the hypoxia-induced atrial profibrotic response occurs mainly via the ROS/JNK pathway, its downstream upregulation of HIF-1α and c-Jun/ATF2 phosphorylation and nuclear translocation to up-regulate the expression of fibrosis-related proteins (COL1A, COL3A, TGF-β1 and α-SMA). Our result suggests that suppression of ROS/JNK signaling pathway is a critical mechanism for developing a novel therapeutic strategy against atrial fibrillation.     

Rosiglitasone and ROCK Inhibitors Modulate Fibrogenetic Changes in TGF-β2 Treated Human Conjunctival Fibroblasts (HconF) in Different Manners

Purpose: The effects of Rho-associated coiled-coil containing protein kinase (ROCK) 1 and 2 inhibitor, ripasudil hydrochloride hydrate (Rip), ROCK2 inhibitor, KD025 or rosiglitazone (Rosi) on two-dimension (2D) and three-dimension (3D) cultured human conjunctival fibroblasts (HconF) treated by transforming growth factor (TGFβ2) were studied. Methods: Two-dimension and three-dimension cultured HconF were examined by transendothelial electrical resistance (TEER, 2D), size and stiffness (3D), and the expression of the extracellular matrix (ECM) including collagen1 (COL1), COL4 and COL6, fibronectin (FN), and α-smooth muscle actin (αSMA) by quantitative PCR (2D, 3D) in the presence of Rip, KD025 or Rosi. Results: TGFβ2 caused a significant increase in (1) the TEER values (2D) which were greatly reduced by Rosi, (2) the stiffness of the 3D organoids which were substantially reduced by Rip or KD025, and (3) TGFβ2 induced a significant up-regulation of all ECMs, except for COL6 (2D) or αSMA (3D), and down-regulation of COL6 (2D). Rosi caused a significant up-regulation of COL1, 4 and 6 (3D), and down-regulation of COL6 (2D) and αSMA (3D). Most of these TGFβ2-induced expressions in the 2D and αSMA in the 3D were substantially inhibited by KD025, but COL4 and αSMA in 2D were further enhanced by Rip. Conclusion: The findings reported herein indicate that TGFβ2 induces an increase in fibrogenetic changes on the plane and in the spatial space, and are inhibited by Rosi and ROCK inhibitors, respectively.     

Interleukin-1β Modulation of the Mechanobiology of Primary Human Pulmonary Fibroblasts: Potential Implications in Lung Repair

Pro-inflammatory cytokines like interleukin-1β (IL-1β) are upregulated during early responses to tissue damage and are expected to transiently compromise the mechanical microenvironment. Fibroblasts are key regulators of tissue mechanics in the lungs and other organs. However, the effects of IL-1β on fibroblast mechanics and functions remain unclear. Here we treated human pulmonary fibroblasts from control donors with IL-1β and used Atomic Force Microscopy to unveil that IL-1β significantly reduces the stiffness of fibroblasts concomitantly with a downregulation of filamentous actin (F-actin) and alpha-smooth muscle (α-SMA). Likewise, COL1A1 mRNA was reduced, whereas that of collagenases MMP1 and MMP2 were upregulated, favoring a reduction of type-I collagen. These mechanobiology changes were functionally associated with reduced proliferation and enhanced migration upon IL-1β stimulation, which could facilitate lung repair by drawing fibroblasts to sites of tissue damage. Our observations reveal that IL-1β may reduce local tissue rigidity by acting both intracellularly and extracellularly through the downregulation of fibroblast contractility and type I collagen deposition, respectively. These IL-1β-dependent mechanical effects may enhance lung repair further by locally increasing pulmonary tissue compliance to preserve normal lung distension and function. Moreover, our results support that IL-1β provides innate anti-fibrotic protection that may be relevant during the early stages of lung repair.     

BMP3 Alone and Together with TGF-β Promote the Differentiation of Human Mesenchymal Stem Cells into a Nucleus Pulposus-Like Phenotype

Human mesenchymal stem cells (MSCs) have the potential to differentiate into nucleus pulposus (NP)-like cells under specific stimulatory conditions. Thus far, the effects of bone morphogenetic protein 3 (BMP3) and the cocktail effects of BMP3 and transforming growth factor (TGF)-β on MSC proliferation and differentiation remain obscure. Therefore, this study was designed to clarify these unknowns. MSCs were cultured with various gradients of BMP3 and BMP3/TGF-β, and compared with cultures in basal and TGF-β media. Cell proliferation, glycosaminoglycan (GAG) content, gene expression, and signaling proteins were measured to assess the effects of BMP3 and BMP3/TGF-β on MSCs. Cell number and GAG content increased upon the addition of BMP3 in a dose-dependent manner. The expression of COL2A1, ACAN, SOX9, and KRT19 increased following induction with BMP3 and TGF-β, in contrast to that of COL1A1, ALP, OPN, and COMP. Smad3 phosphorylation was upregulated by BMP3 and TGF-β, but BMP3 did not affect the phosphorylation of extracellular-signal regulated kinase (ERK) 1/2 or c-Jun N-terminal kinase (JNK). Our results reveal that BMP3 enhances MSC proliferation and differentiation into NP-like cells, as indicated by increased cell numbers and specific gene expressions, and may also cooperate with TGF-β induced positive effects. These actions are likely related to the activation of TGF-β signaling pathway.     

Targeting lncRNA H19/miR-29b/COL1A1 Axis Impedes Myofibroblast Activities of Precancerous Oral Submucous Fibrosis

Oral submucous fibrosis (OSF) is known as a potentially malignant disorder, which may result from chemical irritation due to areca nuts (such as arecoline). Emerging evidence suggests that fibrogenesis and carcinogenesis are regulated by the interaction of long noncoding RNAs (lncRNAs) and microRNAs. Among these regulators, profibrotic lncRNA H19 has been found to be overexpressed in several fibrosis diseases. Here, we examined the expression of H19 in OSF specimens and its functional role in fibrotic buccal mucosal fibroblasts (fBMFs). Our results indicate that the aberrantly overexpressed H19 contributed to higher myofibroblast activities, such as collagen gel contractility and migration ability. We also demonstrated that H19 interacted with miR-29b, which suppressed the direct binding of miR-29b to the 3′-untranslated region of type I collagen (COL1A1). We showed that ectopic expression of miR-29b ameliorated various myofibroblast phenotypes and the expression of α-smooth muscle actin (α-SMA), COL1A1, and fibronectin (FN1) in fBMFs. In OSF tissues, we found that the expression of miR-29b was downregulated and there was a negative correlation between miR-29b and these fibrosis markers. Lastly, we demonstrate that arecoline stimulated the upregulation of H19 through the transforming growth factor (TGF)-β pathway. Altogether, this study suggests that increased TGF-β secretion following areca nut chewing may induce the upregulation of H19, which serves as a natural sponge for miR-29b and impedes its antifibrotic effects.     

CRISPR/Cas9-Mediated Allele-Specific Disruption of a Dominant COL6A1 Pathogenic Variant Improves Collagen VI Network in Patient Fibroblasts

Collagen VI-related disorders are the second most common congenital muscular dystrophies for which no treatments are presently available. They are mostly caused by dominant-negative pathogenic variants in the genes encoding α chains of collagen VI, a heteromeric network forming collagen; for example, the c.877G>A; p.Gly293Arg COL6A1 variant, which alters the proper association of the tetramers to form microfibrils. We tested the potential of CRISPR/Cas9-based genome editing to silence or correct (using a donor template) a mutant allele in the dermal fibroblasts of four individuals bearing the c.877G>A pathogenic variant. Evaluation of gene-edited cells by next-generation sequencing revealed that correction of the mutant allele by homologous-directed repair occurred at a frequency lower than 1%. However, the presence of frameshift variants and others that provoked the silencing of the mutant allele were found in >40% of reads, with no effects on the wild-type allele. This was confirmed by droplet digital PCR with allele-specific probes, which revealed a reduction in the expression of the mutant allele. Finally, immunofluorescence analyses revealed a recovery in the collagen VI extracellular matrix. In summary, we demonstrate that CRISPR/Cas9 gene-edition can specifically reverse the pathogenic effects of a dominant negative variant in COL6A1.     

Astragalus membranaceus Inhibits Peritoneal Fibrosis via Monocyte Chemoattractant Protein (MCP)-1 and the Transforming Growth Factor-β1 (TGF-β1) Pathway in Rats Submitted to Peritoneal Dialysis

Inflammation and transforming growth factor-β1 (TGF-β1) contribute to the development of peritoneal fibrosis (PF), which is associated with peritoneal dialysis (PD). Astragalus membranaceus (Astragalus) has anti-inflammatory and anti-fibrotic effects in many diseases. The goal of this study was to determine the anti-fibrotic effects of Astragalus on the PF response to PD. A rat model of PD was induced using standard PD fluid, and PF was verified by HE and Masson’s staining, as well as through the expression of fibroblast surface protein (FSP) and collagen III. The expression levels of monocyte chemoattractant protein (MCP)-1, F4/80 (macrophage/monocyte marker in rat), TGF-β1 and the downstream proteins phospho-SMAD 2/3 in dialyzed peritoneal tissue treated with or without Astragalus was evaluated using immunohistochemistry analysis. Overall correlations between MCP-1 and TGF-β1 staining were analyzed using both the Spearman and Pearson methods. The results showed that Astragalus could inhibit the recruitment and activation of monocytes/macrophages, thereby reducing the production of TGF-β1 in the dialyzed peritoneal membrane. PF was also significantly decreased following treatment with Astragalus. MCP-1 expression had a strong positive correlation with TGF-β1 sensitivity, suggesting that the anti-fibrotic function of Astragalus was mediated by MCP-1 and the TGF-β1 pathway. Our results indicate that Astragalus could be a useful agent against PD-induced PF.     

Differences between Mice and Humans in Regulation and the Molecular Network of Collagen,Type III,Alpha-1 at the Gene Expression Level: Obstacles that Translational Research Must Overcome

Collagen, type III, alpha-1 (COL3A1) is essential for normal collagen I fibrillogenesis in many organs. There are differences in phenotypes of mutations in the COL3A1 gene in humans and mutations in mice. In order to investigate whether the regulation and gene network of COL3A1 is the same in healthy populations of mice and humans, we compared the quantitative trait loci (QTL) that regulate the expression level of COL3A1 and the gene network of COL3A1 pathways between humans and mice using whole genome expression profiles. Our results showed that, for the regulation of expression of Col3a1 in mice, an eQTL on chromosome (Chr) 12 regulates the expression of Col3a1. However, expression of genes in the syntenic region on human Chr 7 has no association with the expression level of COL3A1. For the gene network comparison, we identified 44 top genes whose expression levels are strongly associated with that of Col3a1 in mice. We next identified 41 genes strongly associated with the expression level of COL3A1 in humans. There are a few but significant differences in the COL3A1 gene network between humans and mice. Several genes showed opposite association with expression of COL3A1. These genes are known to play important roles in development and function of the extracellular matrix of the lung. Difference in the molecular pathway of key genes in the COL3A1 gene network in humans and mice suggest caution should be used in extrapolating results from models of human lung diseases in mice to clinical lung diseases in humans. These differences may influence the efficacy of drugs in humans whose development employed mouse models.     

The Role of GRP and MGP in the Development of Non-Hemorrhagic VKCFD1 Phenotypes

Vitamin K dependent coagulation factor deficiency type 1 (VKCFD1) is a rare hereditary bleeding disorder caused by mutations in γ-Glutamyl carboxylase (GGCX) gene. The GGCX enzyme catalyzes the γ-carboxylation of 15 different vitamin K dependent (VKD) proteins, which have function in blood coagulation, calcification, and cell signaling. Therefore, in addition to bleedings, some VKCFD1 patients develop diverse non-hemorrhagic phenotypes such as skin hyper-laxity, skeletal dysmorphologies, and/or cardiac defects. Recent studies showed that GGCX mutations differentially effect γ-carboxylation of VKD proteins, where clotting factors are sufficiently γ-carboxylated, but not certain non-hemostatic VKD proteins. This could be one reason for the development of diverse phenotypes. The major manifestation of non-hemorrhagic phenotypes in VKCFD1 patients are mineralization defects. Therefore, the mechanism of regulation of calcification by specific VKD proteins as matrix Gla protein (MGP) and Gla-rich protein (GRP) in physiological and pathological conditions is of high interest. This will also help to understand the patho-mechanism of VKCFD1 phenotypes and to deduce new treatment strategies. In the present review article, we have summarized the recent findings on the function of GRP and MGP and how these proteins influence the development of non-hemorrhagic phenotypes in VKCFD1 patients.     

Sodium Hydrosulfide Prevents Myocardial Dysfunction through Modulation of Extracellular Matrix Accumulation and Vascular Density

The aim was to examine the role of exogenous hydrogen sulfide (H₂S) on cardiac remodeling in post-myocardial infarction (MI) rats. MI was induced in rats by ligation of coronary artery. After treatment with sodium hydrosulfide (NaHS, an exogenous H₂S donor, 56 μM/kg·day) for 42 days, the effects of NaHS on left ventricular morphometric features, echocardiographic parameters, heme oxygenase-1 (HO-1), matrix metalloproteinases-9 (MMP-9), type I and type III collagen, vascular endothelial growth factor (VEGF), CD34, and α-smooth muscle actin (α-SMA) in the border zone of infarct area were analyzed to elucidate the protective mechanisms of exogenous H₂S on cardiac function and fibrosis. Forty-two days post MI, NaHS-treatment resulted in a decrease in myocardial fibrotic area in association with decreased levels of type I, type III collagen and MMP-9 and improved cardiac function. Meanwhile, NaHS administration significantly increased cystathionine γ-lyase (CSE), HO-1, α-SMA, and VEGF expression. This effect was accompanied by an increase in vascular density in the border zone of infarcted myocardium. Our results provided the strong evidences that exogenous H₂S prevented cardiac remodeling, at least in part, through inhibition of extracellular matrix accumulation and increase in vascular density.     

Development of Minicircle Vectors Encoding COL7A1 Gene with Human Promoters for Non-Viral Gene Therapy for Recessive Dystrophic Epidermolysis Bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare autosomal inherited skin disorder caused by mutations in the COL7A1 gene that encodes type VII collagen (C7). The development of an efficient gene replacement strategy for RDEB is mainly hindered by the lack of vectors able to encapsulate and transfect the large cDNA size of this gene. To address this problem, our group has opted to use polymeric-based non-viral delivery systems and minicircle DNA. With this approach, safety is improved by avoiding the usage of viruses, the absence of bacterial backbone, and the replacement of the control viral cytomegalovirus (CMV) promoter of the gene with human promoters. All the promoters showed impressive C7 expression in RDEB skin cells, with eukaryotic translation elongation factor 1 α (EF1α) promoter producing higher C7 expression levels than CMV following minicircle induction, and COL7A1 tissue-specific promoter (C7P) generating C7 levels similar to normal human epidermal keratinocytes. The improved system developed here has a high potential for use as a non-viral topical treatment to restore C7 in RDEB patients efficiently and safely, and to be adapted to other genetic conditions.     

AP2M1 Supports TGF-β Signals to Promote Collagen Expression by Inhibiting Caveolin Expression

The extracellular matrix (ECM) is important for normal development and disease states, including inflammation and fibrosis. To understand the complex regulation of ECM, we performed a suppressor screening using Caenorhabditis elegans expressing the mutant ROL-6 collagen protein. One cuticle mutant has a mutation in dpy-23 that encodes the μ2 adaptin (AP2M1) of clathrin-associated protein complex II (AP-2). The subsequent suppressor screening for dpy-23 revealed the lon-2 mutation. LON-2 functions to regulate body size through negative regulation of the tumor growth factor-beta (TGF-β) signaling pathway responsible for ECM production. RNA-seq analysis showed a dominant change in the expression of collagen genes and cuticle components. We noted an increase in the cav-1 gene encoding caveolin-1, which functions in clathrin-independent endocytosis. By knockdown of cav-1, the reduced TGF-β signal was significantly restored in the dpy-23 mutant. In conclusion, the dpy-23 mutation upregulated cav-1 expression in the hypodermis, and increased CAV-1 resulted in a decrease of TβRI. Finally, the reduction of collagen expression including rol-6 by the reduced TGF-β signal influenced the cuticle formation of the dpy-23 mutant. These findings could help us to understand the complex process of ECM regulation in organism development and disease conditions.     

Decorin—An Antagonist of TGF-β in Astrocytes of the Optic Nerve

During the pathogenesis of glaucoma, optic nerve (ON) axons become continuously damaged at the optic nerve head (ONH). This often is associated with reactive astrocytes and increased transforming growth factor (TGF-β) 2 levels. In this study we tested the hypothesis if the presence or absence of decorin (DCN), a small leucine-rich proteoglycan and a natural inhibitor of several members of the TGF family, would affect the expression of the TGF-βs and connective tissue growth factor (CTGF/CCN2) in human ONH astrocytes and murine ON astrocytes. We found that DCN is present in the mouse ON and is expressed by human ONH and murine ON astrocytes. DCN expression and synthesis was significantly reduced after 24 h treatment with 3 nM CTGF/CCN2, while treatment with 4 pM TGF-β2 only reduced expression of DCN significantly. Conversely, DCN treatment significantly reduced the expression of TGF-β1, TGF-β2 and CTGF/CCN2 vis-a-vis untreated controls. Furthermore, DCN treatment significantly reduced expression of fibronectin (FN) and collagen IV (COL IV). Notably, combined treatment with DCN and triciribine, a small molecule inhibitor of protein kinase B (AKT), attenuated effects of DCN on CTGF/CCN2, TGF-β1, and TGF-β2 mRNA expression. We conclude (1) that DCN is an important regulator of TGF-β and CTGF/CCN2 expression in astrocytes of the ON and ONH, (2) that DCN thereby regulates the expression of extracellular matrix (ECM) components and (3) that DCN executes its negative regulatory effects on TGF-β and CTGF/CCN2 via the pAKT/AKT signaling pathway in ON astrocytes.     

Suppression of PGC-1α Drives Metabolic Dysfunction in TGFβ2-Induced EMT of Retinal Pigment Epithelial Cells

PGC-1α, a key orchestrator of mitochondrial metabolism, plays a crucial role in governing the energetically demanding needs of retinal pigment epithelial cells (RPE). We previously showed that silencing PGC-1α induced RPE to undergo an epithelial-mesenchymal-transition (EMT). Here, we show that induction of EMT in RPE using transforming growth factor-beta 2 (TGFβ2) suppressed PGC-1α expression. Correspondingly, TGFβ2 induced defects in mitochondrial network integrity with increased sphericity and fragmentation. TGFβ2 reduced expression of genes regulating mitochondrial dynamics, reduced citrate synthase activity and intracellular ATP content. High-resolution respirometry showed that TGFβ2 reduced mitochondrial OXPHOS levels consistent with reduced expression of NDUFB5. The reduced mitochondrial respiration was associated with a compensatory increase in glycolytic reserve, glucose uptake and gene expression of glycolytic enzymes (PFKFB3, PKM2, LDHA). Treatment with ZLN005, a selective small molecule activator of PGC-1α, blocked TGFβ2-induced upregulation of mesenchymal genes (αSMA, Snai1, CTGF, COL1A1) and TGFβ2-induced migration using the scratch wound assay. Our data show that EMT is accompanied by mitochondrial dysfunction and a metabolic shift towards reduced OXPHOS and increased glycolysis that may be driven by PGC-1α suppression. ZLN005 effectively blocks EMT in RPE and thus serves as a novel therapeutic avenue for treatment of subretinal fibrosis.     

Resolvin D1 Decreases Severity of Streptozotocin-Induced Type 1 Diabetes Mellitus by Enhancing BDNF Levels,Reducing Oxidative Stress,and Suppressing Inflammation

Type 1 diabetes mellitus is an autoimmune disease characterized by increased production of pro-inflammatory cytokines secreted by infiltrating macrophages and T cells that destroy pancreatic β cells in a free radical-dependent manner that causes decrease or absence of insulin secretion and consequent hyperglycemia. Hence, suppression of pro-inflammatory cytokines and oxidative stress may ameliorate or decrease the severity of diabetes mellitus. To investigate the effect and mechanism(s) of action of RVD1, an anti-inflammatory metabolite derived from docosahexaenoic acid (DHA), on STZ-induced type 1 DM in male Wistar rats, type 1 diabetes was induced by single intraperitoneal (i.p) streptozotocin (STZ-65 mg/kg) injection. RVD1 (60 ng/mL, given intraperitoneally) was administered from day 1 along with STZ for five consecutive days. Plasma glucose, IL-6, TNF-α, BDNF (brain-derived neurotrophic factor that has anti-diabetic actions), LXA4 (lipoxin A4), and RVD1 levels and BDNF concentrations in the pancreas, liver, and brain tissues were measured. Apoptotic (Bcl2/Bax), inflammatory (COX-1/COX-2/Nf-κb/iNOS/PPAR-γ) genes and downstream insulin signaling proteins (Gsk-3β/Foxo1) were measured in the pancreatic tissue along with concentrations of various antioxidants and lipid peroxides. RVD1 decreased severity of STZ-induced type 1 DM by restoring altered plasma levels of TNF-α, IL-6, and BDNF (p < 0.001); expression of pancreatic COX-1/COX-2/PPAR-γ genes and downstream insulin signaling proteins (Gsk-3β/Foxo1) and the concentrations of antioxidants and lipid peroxides to near normal. RVD1 treatment restored expression of Bcl2/Pdx genes, plasma LXA4 (p < 0.001) and RVD1 levels and increased brain, pancreatic, intestine, and liver BDNF levels to near normal. The results of the present study suggest that RVD1 can prevent STZ-induced type 1 diabetes by its anti-apoptotic, anti-inflammatory, and antioxidant actions and by activating the Pdx gene that is needed for pancreatic β cell proliferation.