The role of CTGF in the diabetic rat retina and its relationship with VEGF and TGF-β(2) , elucidated by treatment with CTGFsiRNA

TGF-β Signaling Pathways in the Development of Diabetic Retinopathy

Diabetic retinopathy (DR), a prevalent complication of diabetes mellitus affecting a significant portion of the global population, has long been viewed primarily as a microvascular disorder. However, emerging evidence suggests that it should be redefined as a neurovascular disease with multifaceted pathogenesis rooted in oxidative stress and advanced glycation end products. The transforming growth factor-β (TGF-β) signaling family has emerged as a major contributor to DR pathogenesis due to its pivotal role in retinal vascular homeostasis, endothelial cell barrier function, and pericyte differentiation. However, the precise roles of TGF-β signaling in DR remain incompletely understood, with conflicting reports on its impact in different stages of the disease. Additionally, the BMP subfamily within the TGF-β superfamily introduces further complexity, with BMPs exhibiting both pro- and anti-angiogenic properties. Furthermore, TGF-β signaling extends beyond the vascular realm, encompassing immune regulation, neuronal survival, and maintenance. The intricate interactions between TGF-β and reactive oxygen species (ROS), non-coding RNAs, and inflammatory mediators have been implicated in the pathogenesis of DR. This review delves into the complex web of signaling pathways orchestrated by the TGF-β superfamily and their involvement in DR. A comprehensive understanding of these pathways may hold the key to developing targeted therapies to halt or mitigate the progression of DR and its devastating consequences.

Therapeutic strategies to target connective tissue growth factor in fibrotic lung diseases

The treatment of interstitial lung diseases, including idiopathic pulmonary fibrosis (IPF), remains challenging as current available antifibrotic agents are not effective in halting disease progression. Connective tissue growth factor (CTGF), also known as cellular communication factor 2 (CCN2), is a member of the CCN family of proteins that regulates cell signaling through cell surface receptors such as integrins, the activity of cytokines/growth factors, and the turnover of extracellular matrix (ECM) proteins. Accumulating evidence indicates that CTGF plays a crucial role in promoting lung fibrosis through multiple processes, including inducing transdifferentiation of fibroblasts to myofibroblasts, epithelial-mesenchymal transition (EMT), and cooperating with other fibrotic mediators such as TGF-β. Increased expression of CTGF has been observed in fibrotic lungs and inhibiting CTGF signaling has been shown to suppress lung fibrosis in several animal models. Thus, the CTGF signaling pathway is emerging as a potential therapeutic target in IPF and other pulmonary fibrotic conditions. This review provides a comprehensive overview of the current evidence on the pathogenic role of CTGF in pulmonary fibrosis and discusses the current therapeutic agents targeting CTGF using a systematic review approach.

Connective tissue growth factor: Role in trabecular meshwork remodeling and intraocular pressure lowering

Connective tissue growth factor (CTGF) is a distinct signaling molecule modulating many physiological and pathophysiological processes. This protein is upregulated in numerous fibrotic diseases that involve extracellular matrix (ECM) remodeling. It mediates the downstream effects of transforming growth factor beta (TGF-β) and is regulated via TGF-β SMAD-dependent and SMAD-independent signaling routes. Targeting CTGF instead of its upstream regulator TGF-β avoids the consequences of interfering with the pleotropic effects of TGF-β. Both CTGF and its upstream mediator, TGF-β, have been linked with the pathophysiology of glaucomatous optic neuropathy due to their involvement in the regulation of ECM homeostasis. The excessive expression of these growth factors is associated with glaucoma pathogenesis via elevation of the intraocular pressure (IOP), the most important risk factor for glaucoma. The raised in the IOP is due to dysregulation of ECM turnover resulting in excessive ECM deposition at the site of aqueous humor outflow. It is therefore believed that CTGF could be a potential therapeutic target in glaucoma therapy. This review highlights the CTGF biology and structure, its regulation and signaling, its association with the pathophysiology of glaucoma, and its potential role as a therapeutic target in glaucoma management.

Human retinal secretome: A cross-link between mesenchymal and retinal cells

In recent years, mesenchymal stem cells (MSC) have been considered the most effective source for regenerative medicine, especially due to released soluble paracrine bioactive components and extracellular vesicles. These factors, collectively called the secretome, play crucial roles in immunomodulation and in improving survival and regeneration capabilities of injured tissue. Recently, there has been a growing interest in the secretome released by retinal cytotypes, especially retinal pigment epithelium and Müller glia cells. The latter trophic factors represent the key to preserving morphofunctional integrity of the retina, regulating biological pathways involved in survival, function and responding to injury. Furthermore, these factors can play a pivotal role in onset and progression of retinal diseases after damage of cell secretory function. In this review, we delineated the importance of cross-talk between MSCs and retinal cells, focusing on common/induced secreted factors, during experimental therapy for retinal diseases. The cross-link between the MSC and retinal cell secretomes suggests that the MSC secretome can modulate the retinal cell secretome and vice versa. For example, the MSC secretome can protect retinal cells from degeneration by reducing oxidative stress, autophagy and programmed cell death. Conversely, the retinal cell secretome can influence the MSC secretome by inducing changes in MSC gene expression and phenotype.

mRNA therapy for myocardial infarction: A review of targets and delivery vehicles

Cardiovascular diseases are the leading cause of death in the world. This is partly due to the low regenerative capacity of adult hearts. mRNA therapy is a promising approach under development for cardiac diseases. In mRNA therapy, expression of the target protein is modulated by delivering synthetic mRNA. mRNA therapy benefits cardiac regeneration by increasing cardiomyocyte proliferation, reducing fibrosis, and promoting angiogenesis. Because mRNA is translated in the cytoplasm, the delivery efficiency of mRNA into the cytoplasm and nucleus significantly affects its therapeutic efficacy. To improve delivery efficiency, non-viral vehicles such as lipid nanoparticles have been developed. Non-viral vehicles can protect mRNA from enzymatic degradation and facilitate the cellular internalization of mRNA. In addition to non-viral vehicles, viral vectors have been designed to deliver mRNA templates into cardiac cells. This article reviews lipid nanoparticles, polymer nanoparticles, and viral vectors that have been utilized to deliver mRNA into the heart. Because of the growing interest in lipid nanoparticles, recent advances in lipid nanoparticles designed for cardiac mRNA delivery are discussed. Besides, potential targets of mRNA therapy for myocardial infarction are discussed. Gene therapies that have been investigated in patients with cardiac diseases are analyzed. Reviewing mRNA therapy from a clinically relevant perspective can reveal needs for future investigations.

Behavioral defects and downregulation of hippocampal BDNF and nNOS expression in db/db mice did not improved by chronic TGF-β2 treatment

Epidemiological evidence suggests that there is a link between diabetes and mood disorders, such as depression and anxiety. Although peripheral or central inflammation may explain this link, the molecular mechanisms are not fully understood and few effective treatments for diabetes or mood disorders are available. In the present study, we aimed to determine whether transforming growth factor (TGF)-β2, an anti-inflammatory substance, might represent a potential therapeutic agent for diabetes-related mood behaviors. TGF-β2 expression in the hippocampus is affected by anxiolytic drugs and stress exposure, it is able to cross the blood-brain barrier, and it is as an exercise-induced physiological adipokine that regulates glucose homeostasis. Therefore, we hypothesized that a chronic TGF-β2 infusion would ameliorate diabetes-related glucose intolerance and mood dysregulation. To determine the effects of the chronic administration of TGF-β2 on diabetes, we implanted osmotic pumps containing TGF-β2 into type 2 diabetic mice (db/db mice), and age-matched non-diabetic control wild type mice and db/db mice were infused with vehicle (PBS), for 12 consecutive days. To assess anxiety-like behaviors and glucose homeostasis, the mice underwent elevated plus maze testing and intraperitoneal glucose tolerance testing. Hippocampal and perigonadal visceral white adipose tissue perigonadal white adipose tissue samples were obtained 12 days later. Contrary to our hypothesis, TGF-β2 infusion had no effect on diabetes-related glucose intolerance or diabetes-related behavioral defects, such as inactivity. In db/db mice, the expression of inflammatory markers was high in pgWAT, but not in the hippocampus, and the former was ameliorated by TGF-β2 infusion. The expression of brain-derived neurotrophic factor and neuronal nitric oxide synthase, important regulators of anxiety-like behaviors, was low in db/db mice, but TGF-β2 infusion did not affect their expression. We conclude that although TGF-β2 reduces the expression of pro-inflammatory markers in the adipose tissue of diabetic mice, it does not ameliorate their obesity or mood dysregulation.

Therapeutic Potential of the Combination of Pentoxifylline and Vitamin-E in Inflammatory Bowel Disease: Inhibition of Intestinal Fibrosis

Background: Although intestinal fibrosis is a consequence of recurrent inflammation in Inflammatory bowel disease (IBD), alleviating inflammation alone does not prevent the progression of fibrosis, suggesting that the development of direct anti-fibrotic agents is necessary. This study aimed to evaluate the anti-fibrotic properties of combination treatment with pentoxifylline (PTX) and vitamin E (Vit-E) on human primary intestinal myofibroblasts (HIMFs) and the therapeutic potential of the combination therapy in murine models of IBD. Methods: HIMFs were pretreated with PTX, Vit-E, or both, and incubated with TGF-β1. We performed Western blot, qPCR, collagen staining, and immunofluorescence to estimate the anti-fibrotic effects of PTX and Vit-E. The cytotoxicity of these was investigated through MTT assay. To induce murine models of IBD for in vivo study, C57BL/6 mice were treated with repeated cycles of dextran sulfate sodium (DSS), developing chronic colitis. We examined whether the combined PTX and Vit-E treatment would effectively ameliorate colonic fibrosis in vivo. Results: We found that the co-treatment with PTX and Vit-E suppressed TGF-β1-induced expression of fibrogenic markers, with decreased expression of pERK, pSmad2, and pJNK, more than either treatment alone in HIMFs. Neither PTX nor Vit-E showed any significant cytotoxicity in given concentrations. Consistently with the in vitro results, the co-administration with PTX and Vit-E effectively attenuated colonic fibrosis with recovery from thickening and shortening of colon in murine models of IBD. Conclusions: These findings demonstrated that the combination of PTX and Vit-E exhibits significant anti-fibrotic effects in both HIMFs and in vivo IBD models, providing a promising therapy for IBD.

Multifunctional regulatory protein connective tissue growth factor (CTGF): A potential therapeutic target for diverse diseases

Connective tissue growth factor (CTGF), a multifunctional protein of the CCN family, regulates cell proliferation, differentiation, adhesion, and a variety of other biological processes. It is involved in the disease-related pathways such as the Hippo pathway, p53 and nuclear factor kappa-B (NF-κB) pathways and thus contributes to the developments of inflammation, fibrosis, cancer and other diseases as a downstream effector. Therefore, CTGF might be a potential therapeutic target for treating various diseases. In recent years, the research on the potential of CTGF in the treatment of diseases has also been paid more attention. Several drugs targeting CTGF (monoclonal antibodies FG3149 and FG3019) are being assessed by clinical or preclinical trials and have shown promising outcomes. In this review, the cellular events regulated by CTGF, and the relationships between CTGF and pathogenesis of diseases are systematically summarized. In addition, we highlight the current researches, focusing on the preclinical and clinical trials concerned with CTGF as the therapeutic target.

The efficacy and safety of intravitreal injection of Ranibizumab as pre-treatment for vitrectomy in proliferative diabetic retinopathy with vitreous hemorrhage

Background

Intravitreal injection of anti-vascular endothelial growth factor (VEGF) has become first line therapy for diabetic macular edema. This study evaluated the efficacy and safety of intravitreal injection of Ranibizumab (IVR) as pre-treatment for pars plana vitrectomy in proliferative diabetic retinopathy (PDR) patients with vitreous hemorrhage.

Methods

This pilot randomized controlled trial included 48 eyes with vitreous hemorrhage resulting from active PDR. Eyes were treated with IVR 1 or 3 days before vitrectomy or a sham subconjunctival injection 3 days before surgery. The occurrence of new tractional retinal detachment (TRD), total operation time, and intraoperative findings were compared. The concentrations of VEGF and connective tissue growth factor (CTGF) in aqueous humor and plasma collected at the time of IVR and vitrectomy were determined by ELISA.

Results

None of the patients who received IVR experienced new TRD. Ranibizumab injection improved intraoperative outcomes. The mean concentrations of VEGF in aqueous humor were significantly lower after than before IVR in patients who received IVR 1 and 3 days before surgery (P < 0.001 each). The CTGF/log₁₀ (VEGF) ratio was significantly higher after than before IVR in patients who received IVR 3 days before vitrectomy (P = 0.046).

Conclusion

Preoperative IVR is an effective and safe strategy for the surgical treatment of severe PDR combined with vitreous hemorrhage. IVR 1 and 3 days before surgery can significantly reduce VEGF content in aqueous humor and effectively improve intraoperative conditions without causing TRD.

Trial registration

This study was registered with the Chinese Clinical Trial Registry. Name of the registry: Exploratory analysis of effect of intravitreal ranibizumab as pre-treatment for pars plana vitrectomy in proliferative diabetic retinopathy. Trial registration number: ChiCTR-ONC-16009520. Date of registration: October 20, 2016. URL of trial registry record: http://www.chictr.org.cn/searchprojen.aspx

A Review of the Molecular Mechanisms Underlying Cardiac Fibrosis and Atrial Fibrillation

The cellular and molecular mechanism involved in the pathogenesis of atrial fibrosis are highly complex. We have reviewed the literature that covers the effectors, signal transduction and physiopathogenesis concerning extracellular matrix (ECM) dysregulation and atrial fibrosis in atrial fibrillation (AF). At the molecular level: angiotensin II, transforming growth factor-β1, inflammation, and oxidative stress are particularly important for ECM dysregulation and atrial fibrotic remodelling in AF. We conclude that the Ang-II-MAPK and TGF-β1-Smad signalling pathways play a major, central role in regulating atrial fibrotic remodelling in AF. The above signalling pathways induce the expression of genes encoding profibrotic molecules (MMP, CTGF, TGF-β1). An important mechanism is also the generation of reactive oxygen species. This pathway induced by the interaction of Ang II with the AT₂R receptor and the activation of NADPH oxidase. Additionally, the interplay between cardiac MMPs and their endogenous tissue inhibitors of MMPs, is thought to be critical in atrial ECM metabolism and fibrosis. We also review recent evidence about the role of changes in the miRNAs expression in AF pathophysiology and their potential as therapeutic targets. Furthermore, keeping the balance between miRNA molecules exerting anti-/profibrotic effects is of key importance for the control of atrial fibrosis in AF.

Correlation between ELF-PEMF exposure and Human RPE Cell Proliferation, Apoptosis and Gene Expression

Purpose

Emerging evidence implies that electromagnetic fields (EMFs) can negatively affect angiogenesis. In this regard, the effects of extremely low frequency pulsed electromagnetic field (ELF-PEMF) exposure on the relative expression level of angiogenic factors involved in the pathogenesis of ocular disorders were evaluated in human retinal pigment epithelial (hRPE) cells in order to investigate a noninvasive therapeutic method for patients with several ocular diseases associated with neovascularization.

Methods

After separating hRPE cells from globes, hRPE cells were exposed to 15 mT of ELF-PEMF (120 Hz) at 5, 10, and 15 min for seven days. Cell proliferation and apoptosis of treated cells were evaluated via ELISA assay. Moreover, relative expression changes of HIF-1α, CTGF, VEGFA, MMP-2, cathepsin D, and E2F3 were performed using real-time RT-PCR.

Results

ELF-PEMF exposure had no significant effects on the apoptosis and proliferation rate of hRPE cells. Expression level of HIF-1α, CTGF, VEGFA, MMP-2, cathepsin D, and E2F3 was downregulated following 5 min of ELF-PEMF exposure.

Conclusion

As ELF-PEMF showed inhibitory effects on the expression of angiogenic genes in hRPE cells with no cytotoxic or proliferative side effects, it can be introduced as a useful procedure for managing angiogenesis induced by retinal pathogenesis, although more studies with adequate follow-up in animal models are needed.

Adiponectin, but Not TGF-β1, CTGF, IL-6 or TNF-α, May Be a Potential Anti-Inflammation and Anti-Fibrosis Factor in Keloid

INTRODUCTION

Numerous studies have elucidated adiponectin as a negative impact on inflammation and tissue fibrosis. However, little is known about the relevance between adiponectin and inflammatory factors in keloid.

METHODS

To clarify whether adiponectin plays a role in the inflammation and fibrosis of keloid, 50 patients with keloid and 50 healthy subjects were enrolled, We examined the serum and mRNA expression levels of adiponectin, TGF-β1, CTGF, IL-6 and TNF-α in normal skin tissues and keloid tissues by ELISA and qPCR, respectively. Correlation analysis between serum concentration of adiponectin with Vancouver Scar Scale (VSS) scores and the age of patients with keloid was evaluated, and the adiponectin concentrations in patients with keloid between different genders were measured. We further examined the effects of adiponectin on TGF-β1 mediated expression of collagen I, FN and MMP-1 in normal fibroblasts (NFs) and keloid fibroblasts (KFs).

RESULTS

We discovered that lower serum concentration and mRNA expression of adiponectin, but higher TGF-β1, CTGF, IL-6 and TNF-α levels were measured in patients with keloid compared with those in normal controls. Furthermore, there was a strong inverse correlation between the serum adiponectin levels and VSS scores in patients with keloid, but not in ages, and there was no statistically difference between different genders. Moreover, adiponectin attenuated TGF-β1 mediated expression of collagen I and FN, and upregulated the expression level of MMP-1 in KFs, but not in NFs. In addition, the inhibitory effect of adiponectin on TGF-β1 was attenuated by AMPK inhibitor Compound C, but not PI3K/Akt inhibitor LY294002.

DISCUSSION

Adiponectin may exert an anti-inflammation and anti-fibrosis role in the development of keloid. One of the underlying mechanisms may be the activation of the AMPK signaling pathway.

RNA sequencing reveals BMP4 as a basis for the dual-target treatment of diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR), currently considered as a neurovascular disease, has become the major cause of blindness. More and more scholars believe that DR is no longer just a kind of microvascular disease, but accompanied by retinal neurodegenerative changes. Intravitreal injection of anti-vascular endothelial growth factor (VEGF) drugs is a classic treatment for DR; however, anti-VEGF drugs can exacerbate fibrosis and eventually lead to retinal detachment. The aim of this study was to explore the pathogenesis of DR and identified new treatments that can provide dual-target intervention for angiogenesis and fibrosis.

METHODS

We explored changes in gene expression in high glucose-induced vascular endothelial cells using RNA sequencing (RNA-seq) technology. We identified bone morphogenetic protein 4 (BMP4) and SMAD family member 9 (SMAD9) among 449 differentially expressed genes from RNA-seq data and confirmed the expression of these two genes in the blood of diabetes patients by RT-PCR and in streptozotocin-induced rat retinas by RT-PCR, immunofluorescence, and western blot. Moreover, considering that DR is a multifactorial and multicellular disease, we used hydrogen peroxide (H2O2), advanced glycation end products (AGEs), CoCl2, 4-hydroxynonenal (4-HNE), and hypoxia to induce three human retinal cell types (Müller, retinal pigment epithelium, and human retinal capillary endothelial cells) to simulate the pathogenesis of DR, and MTT experiment, scratch experiment, Transwell experiment, and lumen formation experiment were used to test whether the model was successfully established. Then, we verified the overexpression of these two genes in the cell models by RT-PCR, immunofluorescence, and western blot. We further tested the effects of BMP4 on retinal cells. We use BMP4 to stimulate retinal cells and observe the effect of BMP4 on retinal cells by MTT experiment, scratch experiment, and RT-PCR.

RESULTS

The results demonstrated that BMP4 and SMAD9 were highly expressed in both in vivo and in vitro models, while BMP4 could significantly upregulate the expression of SMAD9 and promote the expression of VEGF and fibrosis factors.

CONCLUSIONS

This study is the first to analyze the mechanism by which high glucose levels affect retinal vascular endothelial cells through RNA transcriptome sequencing and indicates that BMP4 may be a potential target for the dual-target treatment (anti-VEGF and anti-fibrosis) of DR.

KEY MESSAGES

• High-glucose effect on vascular endothelial cell was analyzed by RNA-seq. • KEGG analysis revealed enrichment of TGF-beta signaling pathway. • SMAD9 and BMP4 expression was upregulated in all samples. • Dual-target therapy of PDR by antagonizing BMP4.

Novel use of a chemically modified siRNA for robust and sustainable in vivo gene silencing in the retina

Despite efficient and specific in vitro knockdown, more reliable and convenient methods for in vivo knockdown of target genes remain to be developed particularly for retinal research. Using commercially available and chemically modified siRNA so-called Accell siRNA, we established a novel in vivo gene silencing approach in the rat retina. siRNA designed for knockdown of the house keeping gene Gapdh or four retinal cell type-specific genes (Nefl, Pvalb, Rho and Opn1sw) was injected into the vitreous body, and their retinal mRNA levels were quantified using real-time PCR. Intravitreal injection of siRNA for Gapdh resulted in approximately 40–70% reduction in its retinal mRNA levels, which lasted throughout a 9-day study period. Furthermore, all the selected retinal specific genes were efficiently down-regulated by 60–90% following intravitreal injection, suggesting injected siRNA penetrated into major retinal cell types. These findings were consistent with uniform distribution of a fluorescence-labeled siRNA injected into the vitreous body. Interestingly, gene silencing of Grin1, a core subunit of NMDA receptor, was accompanied by significant prevention from NMDA-induced retinal ganglion cell death. Thus, we provide single intravitreal injection of Accell siRNA as a versatile technique for robust and sustainable in vivo retinal gene silencing to characterize their biological functions under physiological and pathophysiological conditions.

Connective Tissue Growth Factor: From Molecular Understandings to Drug Discovery

Connective tissue growth factor (CTGF) is a key signaling and regulatory molecule involved in different biological processes, such as cell proliferation, angiogenesis, and wound healing, as well as multiple pathologies, such as tumor development and tissue fibrosis. Although the underlying mechanisms of CTGF remain incompletely understood, a commonly accepted theory is that the interactions between different protein domains in CTGF and other various regulatory proteins and ligands contribute to its variety of functions. Here, we highlight the structure of each domain of CTGF and its biology functions in physiological conditions. We further summarized main diseases that are deeply influenced by CTGF domains and the potential targets of these diseases. Finally, we address the advantages and disadvantages of current drugs targeting CTGF and provide the perspective for the drug discovery of the next generation of CTGF inhibitors based on aptamers.

Retinal capillary basement membrane thickening: Role in the pathogenesis of diabetic retinopathy

Vascular basement membrane (BM) thickening has been hailed over half a century as the most prominent histological lesion in diabetic microangiopathy, and represents an early ultrastructural change in diabetic retinopathy (DR). Although vascular complications of DR have been clinically well established, specific cellular and molecular mechanisms underlying dysfunction of small vessels are not well understood. In DR, small vessels develop insidiously as BM thickening occurs. Studies examining high resolution imaging data have established BM thickening as one of the foremost structural abnormalities of retinal capillaries. This fundamental structural change develops, at least in part, from excess accumulation of BM components. Although BM thickening is closely associated with the development of DR, its contributory role in the pathogenesis of DR is coming to light recently. DR develops over several years before clinical manifestations appear, and it is during this clinically silent period that hyperglycemia induces excess synthesis of BM components, contributes to vascular BM thickening, and promotes structural and functional lesions including cell death and vascular leakage in the diabetic retina. Studies using animal models show promising results in preventing BM thickening with subsequent beneficial effects. Several gene regulatory approaches are being developed to prevent excess synthesis of vascular BM components in an effort to reduce BM thickening. This review highlights current understanding of capillary BM thickening development, role of BM thickening in retinal vascular lesions, and strategies for preventing vascular BM thickening as a potential therapeutic strategy in alleviating characteristic lesions associated with DR.

The Role of Transforming Growth Factor-Beta in Retinal Ganglion Cells with Hyperglycemia and Oxidative Stress

A characteristic of diabetes mellitus is hyperglycemia, which is considered with an emphasis on the diabetic retinopathy of progressive neurodegenerative disease. Retinal ganglion cells (RGCs) are believed to be important cells affected in the pathogenesis of diabetic retinopathy. Transforming growth factor-beta (TGF-β) is a neuroprotective protein that helps to withstand various neuronal injuries. To investigate the potential roles and regulatory mechanisms of TGF-β in hyperglycemia-triggered damage of RGCs in vitro, we established RGCs in 5.5, 25, 50, and 100 mM D-glucose supplemented media and focused on the TGF-β-related oxidative stress pathway in combination with hydrogen peroxide (H₂O₂). Functional experiments showed that TGF-β1/2 protein expression was upregulated in RGCs with hyperglycemia. The knockdown of TGF-β enhanced the accumulation of reactive oxygen species (ROS), inhibited the cell proliferation rate, and reduced glutathione content in hyperglycemia. Furthermore, the results showed that the TGF-β-mediated enhancement of antioxidant signaling was correlated with the activation of stress response proteins and the antioxidant pathway, such as aldehyde dehydrogenase 3A1 (ALDH3A1), heme oxygenase-1 (HO-1), nuclear factor erythroid 2-related factor (Nrf2), and hypoxia-inducible factor (HIF-1α). Summarizing, our results demonstrated that TGF-β keeps RGCs from hyperglycemia-triggered harm by promoting the activation of the antioxidant pathway, suggesting a potential anti-diabetic therapy for the treatment of diabetic retinopathy.

Blocking CTGF/CCN2 reduces established skeletal muscle fibrosis in a rat model of overuse injury

Tissue fibrosis is a hallmark of overuse musculoskeletal injuries and contributes to functional declines. We tested whether inhibition of CCN2 (cellular communication network factor 2, previously known as connective tissue growth factor, CTGF) using a specific antibody (termed FG‐3019 or pamrevlumab) reduces established overuse‐induced muscle fibrosis in a clinically relevant rodent model of upper extremity overuse injury. Young adult rats performed a high repetition high force (HRHF) reaching and lever‐pulling task for 18 weeks, after first being shaped for 6 weeks to learn this operant task. Rats were then euthanized (HRHF‐Untreated), or rested and treated for 6 weeks with FG‐3019 (HRHF‐Rest/FG‐3019) or a human IgG as a vehicle control (HRHF‐Rest/IgG). HRHF‐Untreated and HRHF‐Rest/IgG rats had higher muscle levels of several fibrosis‐related proteins (TGFβ1, CCN2, collagen types I and III, and FGF2), and higher muscle numbers of alpha SMA and pERK immunopositive cells, compared to control rats. Each of these fibrogenic changes was restored to control levels by the blocking of CCN2 signaling in HRHF‐Rest/FG‐3019 rats, as were HRHF task‐induced increases in serum CCN2 and pro‐collagen I intact N‐terminal protein. Levels of cleaved CCN3, an antifibrotic protein, were lowered in HRHF‐Untreated and HRHF‐Rest/IgG rats, compared to control rats, yet elevated back to control levels in HRHF‐Rest/FG‐3019 rats. Significant grip strength declines observed in HRHF‐Untreated and HRHF‐Rest/IgG rats, were restored to control levels in HRHF‐Rest/FG‐3019 rats. These results are highly encouraging for use of FG‐3019 for therapeutic treatment of persistent skeletal muscle fibrosis, such as those induced with chronic overuse.

Blocking CCN2 Reduces Progression of Sensorimotor Declines and Fibrosis in a Rat Model of Chronic Repetitive Overuse

Fibrosis may be a key factor in sensorimotor dysfunction in patients with chronic overuse-induced musculoskeletal disorders. Using a clinically relevant rodent model, in which performance of a high demand handle-pulling task induces tissue fibrosis and sensorimotor declines, we pharmacologically blocked cellular communication network factor 2 (CCN2; connective tissue growth factor) with the goal of reducing the progression of these changes. Young adult, female Sprague-Dawley rats were shaped to learn to pull at high force levels (10 min/day, 5 weeks), before performing a high repetition high force (HRHF) task for 3 weeks (2 h/day, 3 days/week). HRHF rats were untreated, or treated in task weeks 2 and 3 with a monoclonal antibody that blocks CCN2 (FG-3019), or a control immunoglobulin G (IgG). Control rats were untreated or received FG-3019, IgG, or vehicle (saline) injections. Mean task reach rate and grasp force were higher in 3-week HRHF + FG-3019 rats, compared with untreated HRHF rats. Grip strength declined while forepaw mechanical sensitivity increased in untreated HRHF rats, compared with controls; changes improved by FG-3019 treatment. The HRHF task increased collagen in multiple tissues (flexor digitorum muscles, nerves, and forepaw dermis), which was reduced with FG-3019 treatment. FG-3019 treatment also reduced HRHF-induced increases in CCN2 and transforming growth factor β in muscles. In tendons, FG-3019 reduced HRHF-induced increases in CCN2, epitendon thickening, and cell proliferation. Our findings indicate that CCN2 is critical to the progression of chronic overuse-induced multi-tissue fibrosis and functional declines. FG-3019 treatment may be a novel therapeutic strategy for overuse-induced musculoskeletal disorders. © 2019 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 37:2004-2018, 2019.

ERK1/2 directly acts on CTGF/CCN2 expression to mediate myocardial fibrosis in cardiomyopathy caused by mutations in the lamin A/C gene

Cardiomyopathy caused by lamin A/C gene mutations (LMNA cardiomyopathy) is characterized by increased myocardial fibrosis, which impairs left ventricular relaxation and predisposes to heart failure, and cardiac conduction abnormalities. While we previously discovered abnormally elevated extracellular signal-regulated kinase 1/2 (ERK1/2) activities in heart in LMNA cardiomyopathy, its role on the development of myocardial fibrosis remains unclear. We now showed that transforming growth factor (TGF)-β/Smad signaling participates in the activation of ERK1/2 signaling in LMNA cardiomyopathy. ERK1/2 acts on connective tissue growth factor (CTGF/CCN2) expression to mediate the myocardial fibrosis and left ventricular dysfunction. Studies in vivo demonstrate that inhibiting CTGF/CCN2 using a specific antibody decreases myocardial fibrosis and improves the left ventricular dysfunction. Together, these findings show that cardiac ERK1/2 activity is modulated in part by TGF-β/Smad signaling, leading to altered activation of CTGF/CCN2 to mediate fibrosis and alter cardiac function. This identifies a novel mechanism in the development of LMNA cardiomyopathy.

Downregulation of miR-30c promotes renal fibrosis by target CTGF in diabetic nephropathy

MicroRNAs (miRs) play important roles in initiation and progression of many pathologic processes. However, the role of miR-30c in diabetic nephropathy (DN) remains unclear. This study was to determine whether miR-30c was involved in the mechanism of renal fibrosis by inhibiting target CTGF expression in DN. In this study, In Situ Hybridization(ISH), RT-PCR, cell transfection, western blotting and laser confocal telescope were used, respectively. ISH showed that miR-30c, concentrated in cytoplasmic foci in the proximity of the nucleus, was mainly localized in glomerular and renal tubular epithelial cells within the cortex. RT-PCR showed that miR-30c expression was significantly decreased in DN (p<0.05), consistent with of the results of ISH. Luciferase reporter gene assays showed that CTGF was a validated target of miR-30c. Furthermore, miR-30c overexpression directly decreased CTGF mRNA and protein. Conversely, miR-30c inhibitor enhanced CTGF expression. Interestingly, miR-30c expression was negatively correlated with ACR (r=-0.870, P=0.003) and positively correlated with Ccr (r=0.8230, P=0.01), whereas it was uncorrelated with KW/BW, SBP, HbA1C, HOMR-IR and T-Cho (p>0.05). More importantly, miR-30c mimics significantly decreased col-IV, FN, GSI, GBM, GA, MRA/CLA and ACR (p<0.05) and, in contrast, slightly but significantly increased Ccr (p<0.05). In conclusion, our results suggested that loss of miR-30c may contribute to the pathogenesis of DN by inhibiting target CTGF expression; replenishing miR-30c may ameliorate renal structure and function by reducing renal fibrosis in DN.

The role of pharmacogenetics and advances in gene therapy in the treatment of diabetic retinopathy

Diabetic retinopathy (DR) and its complications such as diabetic macular edema continue to remain a major cause for legal blindness in the developed world. While the introduction of anti-tVEGF agents has significantly improved visual outcomes of patients with DR, unpredictable response, largely due to genetic polymorphisms, appears to be a challenge with this therapy. With advances in identification of various genetic biomarkers, novel therapeutic strategies consisting of gene transfer are being developed and tested for patients with DR. Application of pharmacogenetic principles appears to be a promising futuristic strategy to attenuate diabetes-mediated retinal vasculopathy. In this comprehensive review, data from recent studies in the field of pharmacogenomics for the treatment of DR have been provided.

Serum Markers of Epithelial Mesenchymal Transition as Predictors of HCV-induced Liver Fibrosis, Cirrhosis and Hepatocellular Carcinoma

Introduction

Hepatitis C virus (HCV) is a major cause of chronic liver disease in Egypt, leading to hepatic fibrosis, liver cirrhosis (LC), and hepatocellular carcinoma (HCC). Liver fibrosis is characterized by excessive deposition of extracellular matrix (ECM). Newly-recognized pathogenic mechanisms point to the epithelial-mesenchymal transition (EMT) of hepatocytes to matrix synthesizing (myo-) fibroblasts. Transforming growth factor-beta (TGF-β1), bone morphogenic protein (BMP)-7, and connective tissue growth factor (CTGF) are biomarkers reflecting the EMT process. YKL-40 is a glycoprotein member of ECM and plays a role in cancer cell proliferation. The purpose of this study was to determine the serum biomarkers of EMT and its impact on the fibrogenic process and tumorigenesis in HCV-genotype 4 patients.

Methods

In this case-control study that was conducted in 2013–2014, 97 HCV-infected patients were subjected to clinical examination, laboratory investigations, and liver biopsy. According to the histopathologic examination, they were classified to F0 (14 cases), F1 (17 cases), F2 (15 cases), F3 (18 cases), F4 (22 cases), and HCC (11 cases). Fifteen age- and gender-matched subjects were included as normal controls. Serum levels of TGF-β1, BMP-7, CTGF, YKL-40 were assessed, and the TGF-β1/BMP-7 ratios were calculated. The data were analyzed by plotting the receiver operating characteristic curve (ROC), Pearson product-moment correlation coefficient, and Spearman’s rank correlation coefficient (Spearman’s rho).

Results

Serum levels of TGF-β1, BMP-7, CTGF, and YKL-40 were significantly increased in all patient groups compared to controls (p < 0.001). LC exhibited the highest CTGF level and YKL-40 was highest in HCC. The TGF-β1/ BMP-7 ratios reflected the progression of EMT from CHC to LC, however, there was no significant difference between LC and HCC. TGF-β1/ BMP-7 ratio is considered to reflect positive correlation with CTGF in LC group (r = 0.629; p < 0.03) and YKL-40 in HCC group (r = 0.504; p < 0.04).

Conclusion

Increased TGF-β1/BMP-7 ratio and CTGF levels reflect the rate of EMT and provide information about fibrogenic activity. Also, this ratio, in association with YKL-40, can be used to predict malignant transformation in HCV-genotype 4 Egyptian patients.

The natural killer cell response and tumor debulking are associated with prolonged survival in recurrent glioblastoma patients receiving dendritic cells loaded with autologous tumor lysates

Recurrent glioblastomas (GBs) are highly aggressive tumors associated with a 6–8 mo survival rate. In this study, we evaluated the possible benefits of an immunotherapeutic strategy based on mature dendritic cells (DCs) loaded with autologous tumor-cell lysates in 15 patients affected by recurrent GB. The median progression-free survival (PFS) of this patient cohort was 4.4 mo, and the median overall survival (OS) was 8.0 mo. Patients with small tumors at the time of the first vaccination (< 20 cm³; n = 8) had significantly longer PFS and OS than the other patients (6.0 vs. 3.0 mo, p = 0.01; and 16.5 vs. 7.0 mo, p = 0.003, respectively). CD8⁺ T cells, CD56⁺ natural killer (NK) cells and other immune parameters, such as the levels of transforming growth factor β, vascular endothelial growth factor, interleukin-12 and interferon γ (IFNγ), were measured in the peripheral blood and serum of patients before and after immunization, which enabled us to obtain a vaccination/baseline ratio (V/B ratio). An increased V/B ratio for NK cells, but not CD8⁺ T cells, was significantly associated with prolonged PFS and OS. Patients exhibiting NK-cell responses were characterized by high levels of circulating IFNγ and E4BP4, an NK-cell transcription factor. Furthermore, the NK cell V/B ratio was inversely correlated with the TGFβ2 and VEGF V/B ratios. These results suggest that tumor-loaded DCs may increase the survival rate of patients with recurrent GB after effective tumor debulking, and emphasize the role of the NK-cell response in this therapeutic setting.

Expression and function of Delta-like ligand 4 in a rat model of retinopathy of prematurity

The Delta-like ligand 4/Notch signaling pathway was shown to participate in the process of retinal development and angiogenesis. However, the function of the Delta-like ligand 4/Notch signaling pathway in retinopathy of prematurity requires further study. Retinopathy of prematurity was induced in 5-day-old Sprague-Dawley rats exposed to hyperoxia for 7 days, and then returned to room air. Reverse transcription-PCR and western blot revealed that Delta-like ligand 4 levels decreased at postnatal day 12 and increased at postnatal day 17 in retinopathy of prematurity rats. Flat-mounted adenosine diphosphatase stained retina and hematoxylin-eosin stained retinal tissue slices showed that the clock hour scores and the nuclei counts in retinopathy of prematurity rats were significantly different compared to normal control rats. After retinopathy of prematurity rats were intravitreally injected with Delta-like ligand 4 monoclonal antibody to inhibit the Delta-like ligand 4/Notch signaling pathway, there was a significant increase in the severity of retinal neovascularization (clock hours) in the intravitreally injected eyes. The nuclei count was highly correlated with the clock hour score. These results suggest that Delta-like ligand 4/Notch signaling plays an essential role in the process of physiological and pathological angiogenesis in the retina.

Small-interfering RNAs (siRNAs) as a promising tool for ocular therapy

RNA interference (RNAi) can be used to inhibit the expression of specific genes in vitro and in vivo, thereby providing an extremely useful tool for investigating gene function. Progress in the understanding of RNAi-based mechanisms has opened up new perspectives in therapeutics for the treatment of several diseases including ocular disorders. The eye is currently considered a good target for RNAi therapy mainly because it is a confined compartment and, therefore, enables local delivery of small-interfering RNAs (siRNAs) by topical instillation or direct injection. However, delivery strategies that protect the siRNAs from degradation and are suitable for long-term treatment would be help to improve the efficacy of RNAi-based therapies for ocular pathologies. siRNAs targeting critical molecules involved in the pathogenesis of glaucoma, retinitis pigmentosa and neovascular eye diseases (age-related macular degeneration, diabetic retinopathy and corneal neovascularization) have been tested in experimental animal models, and clinical trials have been conducted with some of them. This review provides an update on the progress of RNAi in ocular therapeutics, discussing the advantages and drawbacks of RNAi-based therapeutics compared to previous treatments.

Intravitreal injection of ranibizumab and CTGF shRNA improves retinal gene expression and microvessel ultrastructure in a rodent model of diabetes

Therapeutic modalities targeting vascular endothelial growth factor (VEGF) have been used to treat neovascularization and macular edema. However, anti-VEGF treatment alone may cause up-regulation of connective tissue growth factor (CTGF) in the retina, increasing the risk of fibrosis and tractional retinal detachment. Therefore, in this study, we employ a novel dual-target intervention that involves intravitreal injection of the VEGF inhibitor ranibizumab and a transfection reagent-treated non-viral vector carrying anti-CTGF short hairpin RNA (shRNA) driven by human RNA polymerase III promoter U6. The effects of the dual-target intervention on the expression of VEGF and CTGF and on microvessel ultrastructure were examined in retina of streptozocin-induced diabetic rats. CTGF was significantly up-regulated at week 8 after diabetic induction, whereas VEGF was not up-regulated until week 10. The high expression of both genes was maintained at week 12. Transmission electron microscopy also revealed progressive exacerbation of microvessel ultrastructure during the same period. In addition, ranibizumab significantly lowered VEGF but elevated CTGF mRNA, whereas CTGF shRNA significantly reduced the mRNA levels of both CTGF and VEGF in diabetic retinas. Importantly, dual-target intervention normalized the transcript levels of both target genes and ameliorated retinal microvessel ultrastructural damage better than either single-target intervention. These results suggest the advantages of dual-target over single-target interventions in diabetic retina and reveal a novel therapeutic modality for diabetic retinopathy.

Animal models of diabetic retinopathy: summary and comparison

Diabetic retinopathy (DR) is a microvascular complication associated with chronic exposure to hyperglycemia and is a major cause of blindness worldwide. Although clinical assessment and retinal autopsy of diabetic patients provide information on the features and progression of DR, its underlying pathophysiological mechanism cannot be deduced. In order to have a better understanding of the development of DR at the molecular and cellular levels, a variety of animal models have been developed. They include pharmacological induction of hyperglycemia and spontaneous diabetic rodents as well as models of angiogenesis without diabetes (to compensate for the absence of proliferative DR symptoms). In this review, we summarize the existing protocols to induce diabetes using STZ. We also describe and compare the pathological presentations, in both morphological and functional aspects, of the currently available DR animal models. The advantages and disadvantages of using different animals, ranging from zebrafish, rodents to other higher-order mammals, are also discussed. Until now, there is no single model that displays all the clinical features of DR as seen in human. Yet, with the understanding of the pathological findings in these animal models, researchers can select the most suitable models for mechanistic studies or drug screening.

Angiofibrotic response to vascular endothelial growth factor inhibition in diabetic retinal detachment: report no. 1

OBJECTIVES To assess the effect of bevacizumab injection on connective tissue growth factor (CTGF) and vascular endothelial growth factor (VEGF) in the ocular fluids of patients with diabetic traction retinal detachment, and to determine whether intraoperative and postoperative complications are decreased in eyes given adjunctive preoperative bevacizumab injection. METHODS Twenty eyes of 19 patients were randomized to receive intravitreal bevacizumab or sham injection 3 to 7 days before vitrectomy for severe proliferative diabetic retinopathy. We collected aqueous samples before injection and at the time of vitrectomy and extracted undiluted vitreous samples. RESULTS Five eyes had decreased vascularization of membranes from preinjection to the time of vitrectomy (all in the bevacizumab treatment arm). Median visual acuities were 20/400 in control eyes at baseline and postoperative month 3 (POM3) and 8/200 in the bevacizumab-treated group at baseline and 20/100 at POM3 (P= .30 between control and bevacizumab-treated groups at POM3). All retinas were attached at POM3. Vitreous levels of VEGF were significantly lower in the bevacizumab group than in the control group (P= .03). Vitreous levels of CTGF were slightly lower in the bevacizumab group compared with the control group, but this difference was not statistically significant (P= .38). Levels of CTGF in the aqueous were strongly correlated with CTGF levels in the vitreous of controls (Spearman correlation coefficient, 0.95 [P< .001]). CONCLUSIONS Intravitreal bevacizumab injection reduces vitreous levels of VEGF and produces a clinically observable alteration in diabetic fibrovascular membranes. Ocular fluid levels of CTGF are not significantly affected within the week after VEGF inhibition. Retinal reattachment rates and visual acuity are not significantly altered by preoperative intravitreal bevacizumab injection at POM3. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01270542.

Differential regulation of embryonic and adult β cell replication

Diabetes results from an inadequate functional β cell mass, either due to autoimmune destruction (Type 1 diabetes) or insulin resistance combined with β cell failure (Type 2 diabetes). Strategies to enhance β cell regeneration or increase cell proliferation could improve outcomes for patients with diabetes. Research conducted over the past several years has revealed that factors regulating embryonic β cell mass expansion differ from those regulating replication ofβ cells post-weaning. This article aims to compare and contrast factors known to control embryonic and postnatal β cell replication. In addition, we explore the possibility that connective tissue growth factor (CTGF) could increase adult β cell replication. We have already shown that CTGF is required for embryonicβ cell proliferation and is sufficient to induce replication of embryonic β cells. Here we examine whether adult β cell replication and expansion of β cell mass can be enhanced by increased CTGF expression in mature β cells.

CTGF is a central mediator of tissue remodeling and fibrosis and its inhibition can reverse the process of fibrosis

CTGF is a secreted matricellular protein with very complex biology. It has been shown to modulate many signaling pathways leading to cell adhesion and migration, angiogenesis, myofibroblast activation, and extracellular matrix deposition and remodeling, which together lead to tissue remodeling and fibrosis. It has been reported in the literature that inhibition of CTGF expression by siRNA prevents CCl4-induced liver fibrosis and can reverse fibrosis when administered after significant collagen deposition is observed. A monoclonal antibody to CTGF that is currently in clinical development (FG-3019) has demonstrated the ability to reverse vascular stiffening and improve cardiac function in a rat model of diabetic complications. FG-3019 has also exhibited activity in a murine radiation-induced pulmonary fibrosis model. When FG-3019 was administered to mice after a significant radiation-induced increase in lung density could be observed by CT imaging, the density of the lungs was observed to decrease over the period during which the antibody was administered and to remain stable after therapy had ceased. When considered together, these data indicate that inhibition of CTGF can prevent and reverse the process of fibrosis.