Decorin treatment of spinal cord injury

C286, an orally available retinoic acid receptor β agonist drug, regulates multiple pathways to achieve spinal cord injury repair

Retinoic acid receptor β2 (RARβ2) is an emerging therapeutic target for spinal cord injuries (SCIs) with a unique multimodal regenerative effect. We have developed a first-in-class RARβ agonist drug, C286, that modulates neuron-glial pathways to induce functional recovery in a rodent model of sensory root avulsion. Here, using genome-wide and pathway enrichment analysis of avulsed rats' spinal cords, we show that C286 also influences the extracellular milieu (ECM). Protein expression studies showed that C286 upregulates tenascin-C, integrin-α9, and osteopontin in the injured cord. Similarly, C286 remodulates these ECM molecules, hampers inflammation and prevents tissue loss in a rodent model of spinal cord contusion C286. We further demonstrate C286's efficacy in human iPSC-derived neurons, with treatment resulting in a significant increase in neurite outgrowth. Additionally, we identify a putative efficacy biomarker, S100B, which plasma levels correlated with axonal regeneration in nerve-injured rats. We also found that other clinically available retinoids, that are not RARβ specific agonists, did not lead to functional recovery in avulsed rats, demonstrating the requirement for RARβ specific pathways in regeneration. In a Phase 1 trial, the single ascending dose (SAD) cohorts showed increases in expression of RARβ2 in white blood cells correlative to increased doses and at the highest dose administered, the pharmacokinetics were similar to the rat proof of concept (POC) studies. Collectively, our data suggests that C286 signalling in neurite/axonal outgrowth is conserved between species and across nerve injuries. This warrants further clinical testing of C286 to ascertain POC in a broad spectrum of neurodegenerative conditions.

Application of LRG mechanism in normal pressure hydrocephalus

Normal pressure hydrocephalus (NPH) is a prevalent type of hydrocephalus, including secondary normal pressure hydrocephalus (SNPH) and idiopathic normal pressure hydrocephalus (INPH). However, its clinical diagnosis and pathological mechanism are still unclear. Leucine-rich α-2 glycoprotein (LRG) is involved in various human diseases, including cancer, diabetes, cardiovascular disease, and nervous system diseases. Now the physiological mechanism of LRG is still being explored. According to the current research results on LRG, we found that the agency of LRG has much to do with the known pathological process of NPH. This review focuses on analyzing the LRG signaling pathways and the pathological mechanism of NPH. According to the collected literature evidence, we speculated that LRG probably be involved in the pathological process of NPH. Finally, based on the mechanism of LRG and NPH, we also summarized the evidence of molecular targeted therapies for future research and clinical application.

Nano-elemental selenium particle developed via supramolecular self-assembly of chondroitin sulfate A and Na2SeO3 to repair cartilage lesions

Cartilage repair is a significant clinical issue due to its restricted ability to regenerate and self-heal after cartilage lesions or degenerative disease. Herein, a nano-elemental selenium particle (chondroitin sulfate A‑selenium nanoparticle, CSA-SeNP) is developed by the supramolecular self-assembly of Na₂SeO₃ and negatively charged chondroitin sulfate A (CSA) via electrostatic interactions or hydrogen bonds followed by in-situ reducing of l-ascorbic acid for cartilage lesions repair. The constructed micelle exhibits a hydrodynamic particle size of 171.50 ± 2.40 nm and an exceptionally high selenium loading capacity (9.05 ± 0.03 %) and can promote chondrocyte proliferation, increase cartilage thickness, and improve the ultrastructure of chondrocytes and organelles. It mainly enhances the sulfation modification of chondroitin sulfate by up-regulating the expression of chondroitin sulfate 4-O sulfotransferase-1, -2, -3, which in turn promotes the expression of aggrecan to repair articular and epiphyseal-plate cartilage lesions. The micelles combine the bio-activity of CSA with selenium nanoparticles (SeNPs), which are less toxic than Na₂SeO₃, and low doses of CSA-SeNP are even superior to inorganic selenium in repairing cartilage lesions in rats. Thus, the developed CSA-SeNP is anticipated to be a promising selenium supplementation preparation in clinical application to address the difficulty of healing cartilage lesions with outstanding repair effects.

Decellularization alters the unfavorable regenerative adverse microenvironment of the injured spinal cord to support neurite outgrowth

Background

Acellular tissue has been transplanted into the injury site as an external microenvironment to intervene with imbalance microenvironment that occurs after spinal cord injury (SCI) and stimulating axonal regeneration, although the mechanism is unclear. Given decellularization is the key means to obtain acellular tissues, we speculated changes in the internal components of tissue caused by decellularization may be the key reason why acellular tissues affect remodeling of the microenvironment.

Methods

Complete spinal cord crush in a mouse model was established, and the dynamic of extracellular matrix (ECM) expression and distribution during SCI was studied with immunohistochemistry (IHC). Normal spinal cord (NSC) and 14-day injury spinal cord (ISC) were obtained to prepare the decellularized NSC (DNSC) and decellularized ISC (DISC) through a well-designed decellularization method, and the decellularization effects were evaluated by residual DNA content determination, hematoxylin and eosin staining (H&E), and IHC. Rat dorsal root ganglia (DRG) were co-cultured with NSC, ISC, DNSC, and DISC to evaluate their effect on neurite outgrowth. Furthermore, the mechanisms by which decellularized tissue promotes axonal growth were explored with proteomics analysis of the protein components and function of 14-day ISC and DISC.

Results

We found the expression of the four main ECM components (collagen type I and IV, fibronectin, and laminin) gradually increased with the progression of SCI compared to NSC, peaking at 14 days of injury then slightly decreasing at 21 days, and the distribution of the four ECM proteins in the ISC also changed dynamically. H&E staining, residual DNA content determination, and IHC showed decellularization removed cellular components and preserved an intact ECM. The results of co-cultured DRG with NSCs, ISCs, DNSCs, and DISCs showed DNSCs and DISCs had a stronger ability in supporting neurite outgrowth than NSC and ISC. We found through proteomics that decellularization could remove proteins associated with inflammatory responses, scarring, and other pathological factors, while completely retaining the ECM proteins.

Conclusions

Taken together, our findings demonstrate decellularization can optimize the imbalanced microenvironment after SCI by removing components that inhibit spinal cord regeneration, providing a theoretical basis for clinical application of acellular tissue transplantation to repair SCI.

Fibrotic Scar in CNS Injuries: From the Cellular Origins of Fibroblasts to the Molecular Processes of Fibrotic Scar Formation

Central nervous system (CNS) trauma activates a persistent repair response that leads to fibrotic scar formation within the lesion. This scarring is similar to other organ fibrosis in many ways; however, the unique features of the CNS differentiate it from other organs. In this review, we discuss fibrotic scar formation in CNS trauma, including the cellular origins of fibroblasts, the mechanism of fibrotic scar formation following an injury, as well as the implication of the fibrotic scar in CNS tissue remodeling and regeneration. While discussing the shared features of CNS fibrotic scar and fibrosis outside the CNS, we highlight their differences and discuss therapeutic targets that may enhance regeneration in the CNS.

Activated endothelial cells induce a distinct type of astrocytic reactivity

Reactive astrogliosis is a universal response of astrocytes to abnormal events and injuries. Studies have shown that proinflammatory microglia can polarize astrocytes (designated A1 astrocytes) toward a neurotoxic phenotype characterized by increased Complement Component 3 (C3) expression. It is still unclear if inflammatory stimuli from other cell types may also be capable of inducing a subset of C3⁺ neurotoxic astrocytes. Here, we show that a subtype of C3⁺ neurotoxic astrocytes is induced by activated endothelial cells that is distinct from astrocytes activated by microglia. Furthermore, we show that endothelial-induced astrocytes have upregulated expression of A1 astrocytic genes and exhibit a distinctive extracellular matrix remodeling profile. Finally, we demonstrate that endothelial-induced astrocytes are Decorin-positive and are associated with vascular amyloid deposits but not parenchymal amyloid plaques in mouse models and AD/CAA patients. These findings demonstrate the existence of potentially extensive and subtle functional diversity of C3⁺-reactive astrocytes.

Injured endothelial cells are shown to induce an A1 phenotype in astrocytes, characterized by a genetic signature associated with extracellular matrix remodeling factors (e.g. decorin and vascular Aß deposits).

Possible Mechanisms for the Effects of Sound Vibration on Human Health

This paper presents a narrative review of research literature to “map the landscape” of the mechanisms of the effect of sound vibration on humans including the physiological, neurological, and biochemical. It begins by narrowing music to sound and sound to vibration. The focus is on low frequency sound (up to 250 Hz) including infrasound (1–16 Hz). Types of application are described and include whole body vibration, vibroacoustics, and focal applications of vibration. Literature on mechanisms of response to vibration is categorized into hemodynamic, neurological, and musculoskeletal. Basic mechanisms of hemodynamic effects including stimulation of endothelial cells and vibropercussion; of neurological effects including protein kinases activation, nerve stimulation with a specific look at vibratory analgesia, and oscillatory coherence; of musculoskeletal effects including muscle stretch reflex, bone cell progenitor fate, vibration effects on bone ossification and resorption, and anabolic effects on spine and intervertebral discs. In every category research on clinical applications are described. The conclusion points to the complexity of the field of vibrational medicine and calls for specific comparative research on type of vibration delivery, amount of body or surface being stimulated, effect of specific frequencies and intensities to specific mechanisms, and to greater interdisciplinary cooperation and focus.

The Pathogenesis of Hydrocephalus Following Aneurysmal Subarachnoid Hemorrhage

Hydrocephalus is a common complication of aneurysmal subarachnoid hemorrhage (aSAH) and reportedly contributes to poor neurological outcomes. In this review, we summarize the molecular and cellular mechanisms involved in the pathogenesis of hydrocephalus following aSAH and summarize its treatment strategies. Various mechanisms have been implicated for the development of chronic hydrocephalus following aSAH, including alterations in cerebral spinal fluid (CSF) dynamics, obstruction of the arachnoid granulations by blood products, and adhesions within the ventricular system. Regarding molecular mechanisms that cause chronic hydrocephalus following aSAH, we carried out an extensive review of animal studies and clinical trials about the transforming growth factor-β/SMAD signaling pathway, upregulation of tenascin-C, inflammation-dependent hypersecretion of CSF, systemic inflammatory response syndrome, and immune dysregulation. To identify the ideal treatment strategy, we discuss the predictive factors of shunt-dependent hydrocephalus between surgical clipping and endovascular coiling groups. The efficacy and safety of other surgical interventions including the endoscopic removal of an intraventricular hemorrhage, placement of an external ventricular drain, the use of intraventricular or cisternal fibrinolysis, and an endoscopic third ventriculostomy on shunt dependency following aSAH were also assessed. However, the optimal treatment is still controversial, and it necessitates further investigations. A better understanding of the pathogenesis of acute and chronic hydrocephalus following aSAH would facilitate the development of treatments and improve the outcome.

Intracellular and Extracellular Markers of Lethality in Osteogenesis Imperfecta: A Quantitative Proteomic Approach

Osteogenesis imperfecta (OI) is a heritable disorder that mainly affects the skeleton. The inheritance is mostly autosomal dominant and associated to mutations in one of the two genes, COL1A1 and COL1A2, encoding for the type I collagen α chains. According to more than 1500 described mutation sites and to outcome spanning from very mild cases to perinatal-lethality, OI is characterized by a wide genotype/phenotype heterogeneity. In order to identify common affected molecular-pathways and disease biomarkers in OI probands with different mutations and lethal or surviving phenotypes, primary fibroblasts from dominant OI patients, carrying COL1A1 or COL1A2 defects, were investigated by applying a Tandem Mass Tag labeling-Liquid Chromatography-Tandem Mass Spectrometry (TMT LC-MS/MS) proteomics approach and bioinformatic tools for comparative protein-abundance profiling. While no difference in α1 or α2 abundance was detected among lethal (type II) and not-lethal (type III) OI patients, 17 proteins, with key effects on matrix structure and organization, cell signaling, and cell and tissue development and differentiation, were significantly different between type II and type III OI patients. Among them, some non-collagenous extracellular matrix (ECM) proteins (e.g., decorin and fibrillin-1) and proteins modulating cytoskeleton (e.g., nestin and palladin) directly correlate to the severity of the disease. Their defective presence may define proband-failure in balancing aberrances related to mutant collagen.

Decorin expression is associated with predictive diffusion MR phenotypes of anti-VEGF efficacy in glioblastoma

Previous data suggest that apparent diffusion coefficient (ADC) imaging phenotypes predict survival response to anti-VEGF monotherapy in glioblastoma. However, the mechanism by which imaging may predict clinical response is unknown. We hypothesize that decorin (DCN), a proteoglycan implicated in the modulation of the extracellular microenvironment and sequestration of pro-angiogenic signaling, may connect ADC phenotypes to survival benefit to anti-VEGF therapy. Patients undergoing resection for glioblastoma as well as patients included in The Cancer Genome Atlas (TCGA) and IVY Glioblastoma Atlas Project (IVY GAP) databases had pre-operative imaging analyzed to calculate pre-operative ADC_L values, the average ADC in the lower distribution using a double Gaussian mixed model. ADC_L values were correlated to available RNA expression from these databases as well as from RNA sequencing from patient derived mouse orthotopic xenograft samples. Targeted biopsies were selected based on ADC values and prospectively collected during resection. Surgical specimens were used to evaluate for DCN RNA and protein expression by ADC value. The IVY Glioblastoma Atlas Project Database was used to evaluate DCN localization and relationship with VEGF pathway via in situ hybridization maps and RNA sequencing data. In a cohort of 35 patients with pre-operative ADC imaging and surgical specimens, DCN RNA expression levels were significantly larger in high ADC_L tumors (41.6 vs. 1.5; P = 0.0081). In a cohort of 17 patients with prospectively targeted biopsies there was a positive linear correlation between ADC_L levels and DCN protein expression between tumors (Pearson R² = 0.3977; P = 0.0066) and when evaluating different targets within the same tumor (Pearson R² = 0.3068; P = 0.0139). In situ hybridization data localized DCN expression to areas of microvascular proliferation and immunohistochemical studies localized DCN protein expression to the tunica adventitia of blood vessels within the tumor. DCN expression positively correlated with VEGFR1 & 2 expression and localized to similar areas of tumor. Increased ADC_L on diffusion MR imaging is associated with high DCN expression as well as increased survival with anti-VEGF therapy in glioblastoma. DCN may play an important role linking the imaging features on diffusion MR and anti-VEGF treatment efficacy. DCN may serve as a target for further investigation and modulation of anti-angiogenic therapy in GBM.

Targeting Aquaporin-4 Subcellular Localization to Treat Central Nervous System Edema

Swelling of the brain or spinal cord (CNS edema) affects millions of people every year. All potential pharmacological interventions have failed in clinical trials, meaning that symptom management is the only treatment option. The water channel protein aquaporin-4 (AQP4) is expressed in astrocytes and mediates water flux across the blood-brain and blood-spinal cord barriers. Here we show that AQP4 cell-surface abundance increases in response to hypoxia-induced cell swelling in a calmodulin-dependent manner. Calmodulin directly binds the AQP4 carboxyl terminus, causing a specific conformational change and driving AQP4 cell-surface localization. Inhibition of calmodulin in a rat spinal cord injury model with the licensed drug trifluoperazine inhibited AQP4 localization to the blood-spinal cord barrier, ablated CNS edema, and led to accelerated functional recovery compared with untreated animals. We propose that targeting the mechanism of calmodulin-mediated cell-surface localization of AQP4 is a viable strategy for development of CNS edema therapies.

Decorin Secreted by Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Induces Macrophage Polarization via CD44 to Repair Hyperoxic Lung Injury

Bronchopulmonary dysplasia (BPD), caused by hyperoxia in newborns and infants, results in lung damage and abnormal pulmonary function. However, the current treatments for BPD are steroidal and pharmacological therapies, which cause neurodevelopmental impairment. Treatment with umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) is an efficient alternative approach. To prevent pulmonary inflammation in BPD, this study investigated the hypothesis that a key regulator was secreted by MSCs to polarize inflammatory macrophages into anti-inflammatory macrophages at inflammation sites. Lipopolysaccharide-induced macrophages co-cultured with MSCs secreted low levels of the inflammatory cytokines, IL-8 and IL-6, but high levels of the anti-inflammatory cytokine, IL-10. Silencing decorin in MSCs suppressed the expression of CD44, which mediates anti-inflammatory activity in macrophages. The effects of MSCs were examined in a rat model of hyperoxic lung damage. Macrophage polarization differed depending on the levels of decorin secreted by MSCs. Moreover, intratracheal injection of decorin-silenced MSCs or MSCs secreting low levels of decorin confirmed impaired alveolarization of damaged lung tissues by down-regulation of decorin. In tissues, a decrease in the anti-inflammatory macrophage marker, CD163, was observed via CD44. Thus, we identified decorin as a key paracrine factor, inducing macrophage polarization via CD44, a master immunoregulator in mesenchymal stem cells.

Moving beyond the glial scar for spinal cord repair

Traumatic spinal cord injury results in severe and irreversible loss of function. The injury triggers a complex cascade of inflammatory and pathological processes, culminating in formation of a scar. While traditionally referred to as a glial scar, the spinal injury scar in fact comprises multiple cellular and extracellular components. This multidimensional nature should be considered when aiming to understand the role of scarring in limiting tissue repair and recovery. In this Review we discuss recent advances in understanding the composition and phenotypic characteristics of the spinal injury scar, the oversimplification of defining the scar in binary terms as good or bad, and the development of therapeutic approaches to target scar components to enable improved functional outcome after spinal cord injury.

Regulation of Myelination by Exosome Associated Retinoic Acid Release from NG2-Positive Cells

In the CNS, oligodendrocytes are responsible for myelin formation and maintenance. Following spinal cord injury, oligodendrocyte loss and an inhibitory milieu compromise remyelination and recovery. Here, we explored the role of retinoic acid receptor-beta (RARβ) signaling in remyelination. Using a male Sprague Dawley rat model of PNS-CNS injury, we show that oral treatment with a novel drug like RARβ agonist, C286, induces neuronal expression of the proteoglycan decorin and promotes myelination and differentiation of oligodendrocyte precursor cells (NG2⁺ cells) in a decorin-mediated neuron–glia cross talk. Decorin promoted the activation of RARα in NG2⁺ cells by increasing the availability of the endogenous ligand RA. NG2⁺ cells synthesize RA, which is released in association with exosomes. We found that decorin prevents this secretion through regulation of the EGFR–calcium pathway. Using functional and pharmacological studies, we further show that RARα signaling is both required and sufficient for oligodendrocyte differentiation. These findings illustrate that RARβ and RARα are important regulators of oligodendrocyte differentiation, providing new targets for myelination.

SIGNIFICANCE STATEMENT This study identifies novel therapeutic targets for remyelination after PNS-CNS injury. Pharmacological and knock-down experiments show that the retinoic acid (RA) signaling promotes differentiation of oligodendrocyte precursor cells (OPCs) and remyelination in a cross talk between neuronal RA receptor-beta (RARβ) and RARα in NG2⁺ cells. We show that stimulation of RARα is required for the differentiation of OPCs and we describe for the first time how oral treatment with a RARβ agonist (C286, currently being tested in a Phase 1 trial, ISRCTN12424734) leads to the endogenous synthesis of RA through retinaldehyde dehydrogenase 2 (Raldh2) in NG2 cells and controls exosome-associated-RA intracellular levels through a decorin–Ca²⁺ pathway. Although RARβ has been implicated in distinct aspects of CNS regeneration, this study identifies a novel function for both RARβ and RARα in remyelination.

Promotion of bone cancer pain development by decorin is accompanied by modification of excitatory synaptic molecules in the spinal cord

Bone cancer pain is refractory to currently available clinical treatment owing to its complicated underlying mechanisms. Studies found that extracellular matrix molecules can participate in the regulation of chronic pain. Decorin is one of the most abundant extracellular matrix molecules, and the present study evaluated the effect of decorin on the development of bone cancer pain. We found that decorin was upregulated in the L4–L6 spinal dorsal horn of the bone cancer pain rats. Spinal microinjection of a decorin-targeting RNAi lentivirus alleviated bone cancer pain-induced mechanical allodynia and reduced the expression of pGluR1-Ser831 in the bone cancer pain rats. Meanwhile, decorin knockdown impaired the excitatory synaptogenesis in cultured neurons and prevented the clustering and insertion of pGluR1-Ser831 into postsynaptic membranes. Taken together, the results of our study suggested that decorin contributes to the development of bone cancer pain possibly by regulating the activity of excitatory synaptic molecules in the spinal cord. Our findings provide a better understanding of the function of decorin as a possible therapeutic target for alleviating bone cancer pain.

Depletion of astrocytic transglutaminase 2 improves injury outcomes

Astrocytes play an indispensable role in maintaining a healthy, functional neural network in the central nervous system (CNS). A primary function of CNS astrocytes is to support the survival and function of neurons. In response to injury, astrocytes take on a reactive phenotype, which alters their molecular functions. Reactive astrocytes have been reported to be both beneficial and harmful to the CNS recovery process subsequent to injury. Understanding the molecular processes and regulatory proteins that determine the extent to which an astrocyte hinders or supports neuronal survival is important within the context of CNS repair. One protein that plays a role in modulating cellular survival is transglutaminase 2 (TG2). Global deletion of TG2 results in beneficial outcomes subsequent to in vivo ischemic brain injury. Ex vivo studies have also implicated TG2 as a negative regulator of astrocyte viability subsequent to injury. In this study we show that knocking down TG2 in astrocytes significantly increases their ability to protect neurons from oxygen glucose deprivation (OGD)/reperfusion injury. To begin to understand how deletion of TG2 in astrocytes improves their ability to protect neurons from injury, we performed transcriptome analysis of wild type and TG2^-/- astrocytes. TG2 deletion resulted in alterations in genes involved in extracellular matrix remodeling, cell adhesion and axon growth/guidance. In addition, the majority of genes that showed increases in the TG2^-/- astrocytes had predicted cJun/AP-1 binding motifs in their promoters. Furthermore, phospho-cJun levels were robustly elevated in TG2^-/- astrocytes, a finding which was consistent with the increase in expression of AP-1 responsive genes. These in vitro data were subsequently extended into an in vivo model to determine whether the absence of astrocytic TG2 improves outcomes after CNS injury. Our results show that, following a spinal cord injury, scar formation is significantly attenuated in mice with astrocyte-specific TG2 deletion compared to mice expressing normal TG2 levels. Taken together, these data indicate that TG2 plays a pivotal role in mediating reactive astrocyte properties following CNS injury. Further, the data suggest that limiting the AP-1 mediated pro-survival injury response may be a contributing factor to that the detrimental effects of astrocytic TG2.

Role of proteoglycans in neuro-inflammation and central nervous system fibrosis

Fibrosis is defined as the thickening and scarring of connective tissue, usually as a consequence of tissue damage. The central nervous system (CNS) is special in the sense that fibrogenic cells are restricted to vascular and meningeal areas. Inflammation and the disruption of the blood-brain barrier can lead to the infiltration of fibroblasts and trigger fibrotic response. While the initial function of the fibrotic tissue is to restore the blood-brain barrier and to limit the site of injury, it also demolishes the structure of extracellular matrix and impedes the healing process by producing inhibitory molecules and forming a physical and biochemical barrier that prevents axon regeneration. As a major constituent in the extracellular matrix, proteoglycans participate in the neuro-inflammation, modulating the fibrotic process. In this review, we will discuss the pathophysiology of fibrosis during acute injuries of the CNS, as well as during chronic neurodegenerative conditions such as Alzheimer's disease, Parkinson's disease, multiple sclerosis and age-related neurodegeneration with focus on the functional roles of proteoglycans.

Regeneration of injured skin and peripheral nerves requires control of wound contraction, not scar formation

We review the mounting evidence that regeneration is induced in wounds in skin and peripheral nerves by a simple modification of the wound healing process. Here, the process of induced regeneration is compared to the other two well-known processes by which wounds close, i.e., contraction and scar formation. Direct evidence supports the hypothesis that the mechanical force of contraction (planar in skin wounds, circumferential in nerve wounds) is the driver guiding the orientation of assemblies of myofibroblasts (MFB) and collagen fibers during scar formation in untreated wounds. We conclude that scar formation depends critically on wound contraction and is, therefore, a healing process secondary to contraction. Wound contraction and regeneration did not coincide during healing in a number of experimental models of spontaneous (untreated) regeneration described in the literature. Furthermore, in other studies in which an efficient contraction-blocker, a collagen scaffold named dermis regeneration template (DRT), and variants of it, were grafted on skin wounds or peripheral nerve wounds, regeneration was systematically observed in the absence of contraction. We conclude that contraction and regeneration are mutually antagonistic processes. A dramatic change in the phenotype of MFB was observed when the contraction-blocking scaffold DRT was used to treat wounds in skin and peripheral nerves. The phenotype change was directly observed as drastic reduction in MFB density, dispersion of MFB assemblies and loss of alignment of the long MFB axes. These observations were explained by the evidence of a surface-biological interaction of MFB with the scaffold, specifically involving binding of MFB integrins α1 β1 and α2 β1 to ligands GFOGER and GLOGER naturally present on the surface of the collagen scaffold. In summary, we show that regeneration of wounded skin and peripheral nerves in the adult mammal can be induced simply by appropriate control of wound contraction, rather than of scar formation.

The histopathological and pharmacodynamic effects of intradetrusor decorin injected in a rabbit partial bladder outlet obstruction model

PURPOSE

To evaluate whether or not the bladder function can be protected by supporting the detrusor with decorin levels during the fibrotic process.

METHODS

Forty-two male rabbits were divided into three main groups, partial bladder outlet obstruction (pBOO) group, pBOO + intradetrusor decorin-injected (IDI) group and control group. Both pBOO and pBOO + IDI groups were divided into three subgroups according to the killing schedule. Histopathological, immunohistochemical and pharmacodynamics studies were performed for the evaluation of fibrotic process and tissue characteristics.

RESULTS

Histopathological evaluation revealed statistically significant high fibrosis levels for both pBOO and pBOO + IDI groups when compared with control. Strikingly the antifibrotic effect of decorin was significant on 2nd, 4th and 8th week and increased as time passed. Immunohistochemical analysis was revealed high expressions of anti-TGF-β1 and decorin levels in all pBOO + IDI groups. Pharmacodynamical results were also revealed better contraction responses in favor of 2nd, 4th and 8th week groups of pBOO + IDI groups, when compared with pBOO groups. In addition, the contraction responses against the depolarizer agent KCl were increased in the three decorin-administrated groups.

CONCLUSION

Our study demonstrates the antifibrotic effects of decorin on bladder fibrosis. Strikingly, this antifibrotic effect is shown in histopathological, immunohistochemical and pharmacodynamics studies. Although further studies are warranted to make more decisive inferences regarding its clinical use, our study has the proper pride to be the first step of this time course.

Contaminants in commercial preparations of 'purified' small leucine-rich proteoglycans may distort mechanistic studies

The present study reports the perplexing results that came about because of seriously impure commercially available reagents. Commercial reagents and chemicals are routinely ordered by scientists and expected to have been rigorously assessed for their purity. Unfortunately, we found this assumption to be risky. Extensive work was carried out within our laboratory using commercially sourced preparations of the small leucine-rich proteoglycans (SLRPs), decorin and biglycan, to investigate their influence on nerve cell growth. Unusual results compelled us to analyse the composition and purity of both preparations of these proteoglycans (PGs) using both mass spectrometry (MS) and Western blotting, with and without various enzymatic deglycosylations. Commercial ‘decorin’ and ‘biglycan’ were found to contain a mixture of PGs including not only both decorin and biglycan but also fibromodulin and aggrecan. The unexpected effects of ‘decorin’ and ‘biglycan’ on nerve cell growth could be explained by these impurities. Decorin and biglycan contain either chondroitin or dermatan sulfate glycosaminoglycan (GAG) chains whereas fibromodulin only contains keratan sulfate and the large (>2500 kDa), highly glycosylated aggrecan contains both keratan and chondroitin sulfate. The different structure, molecular weight and composition of these impurities significantly affected our work and any conclusions that could be made. These findings beg the question as to whether scientists need to verify the purity of each commercially obtained reagent used in their experiments. The implications of these findings are vast, since the effects of these impurities may already have led to inaccurate conclusions and reports in the literature with concomitant loss of researchers’ funds and time.

Methotrexate combined with methylprednisolone for the recovery of motor function and differential gene expression in rats with spinal cord injury

Methylprednisolone is a commonly used drug for the treatment of spinal cord injury, but high doses of methylprednisolone can increase the incidence of infectious diseases. Methotrexate has anti-inflammatory activity and immunosuppressive effects, and can reduce inflammation after spinal cord injury. To analyze gene expression changes and the molecular mechanism of methotrexate combined with methylprednisolone in the treatment of spinal cord injury, a rat model of spinal cord contusion was prepared using the PinPoint™ precision cortical impactor technique. Rats were injected with methylprednisolone 30 mg/kg 30 minutes after injury, and then subcutaneously injected with 0.3 mg/kg methotrexate 1 day after injury, once a day, for 2 weeks. TreadScan gait analysis found that at 4 and 8 weeks after injury, methotrexate combined with methylprednisolone significantly improved hind limb swing time, stride time, minimum longitudinal deviation, instant speed, footprint area and regularity index. Solexa high-throughput sequencing was used to analyze differential gene expression. Compared with methylprednisolone alone, differential expression of 316 genes was detected in injured spinal cord treated with methotrexate and methylprednisolone. The 275 up-regulated genes were mainly related to nerve recovery, anti-oxidative, anti-inflammatory and anti-apoptotic functions, while 41 down-regulated genes were mainly related to proinflammatory and pro-apoptotic functions. These results indicate that methotrexate combined with methylprednisolone exhibited better effects on inhibiting the activity of inflammatory cytokines and enhancing antioxidant and anti-apoptotic effects and thereby produced stronger neuroprotective effects than methotrexate alone. The 316 differentially expressed genes play an important role in the above processes.

Expression of decorin in intestinal tissues of mice with inflammatory bowel disease and its correlation with autophagy

The aim of this study was to investigate the expression of decorin (DCN) in the intestinal tissues of mice with inflammatory bowel disease (IBD) and its correlation with autophagy. The IBD mouse model was created by intrarectal injection of trinitrobenzene sulfonic acid. The pathology of colon tissues of the mice was examined using hematoxylin and eosin staining. Expression of DCN and the proteins associated with autophagy was detected using immunohistochemistry. Normal human colon mucosal epithelial cells (NCM460 cells) were transfected with DCN expression plasmid and the expression of DCN and autophagy-associated proteins was detected by western blot analysis. Cell apoptosis was studied using an Annexin V apoptosis detection assay and intracellular autophagosomes were observed using electron microscopy. The IBD mouse model was successfully established. Thickening, edema and inflammatory cell infiltration of the intestinal wall were observed in the IBD mice. The expression of DCN as well as the autophagy-associated proteins beclin 1 and LC3B, was increased in the intestinal tissues of the IBD mice. Furthermore, in the NCM460 cells transfected with DCN, the expression of beclin 1 and LC3B was upregulated, while p62 expression was downregulated. Intracellular autophagosomes were increased and apoptosis was decreased in the cells with DCN overexpression. Inhibition of autophagy reversed the effects of DCN on apoptosis. Therefore, DCN is able to induce autophagy and protect intestinal cells during the occurrence and development of IBD.

Decorin protects human hepatoma HepG2 cells against oxygen-glucose deprivation via modulating autophagy

This study is to investigate the effects of decorin (DCN) on human hepatoma HepG2 cells under oxygen-glucose deprivation (OGD) condition. HepG2 cells were cultured under OGD condition. CCK-8 assay was used to assess the cell survival, and flow cytometry was performed to detect the apoptosis. Protein expression levels were detected with Western blot analysis. Transfection was performed with liposome, and cells were screened with G418. The cell survival rates were significantly decreased in the OGD groups. When treated with autophagy inhibitor 3-MA, the survival rates were further declined in these cells. Moreover, flow cytometry indicated that apoptosis occurred in the HepG2 cells under OGD condition, and the apoptosis rates were significantly increased by the 3-MA treatment. Western blot analysis showed that, the expression levels of DCN were significantly elevated in OGD-preconditioned HepG2 cells. Meanwhile, the expression level of Beclin1 and the LC3BI/LC3BII ratio were significantly increased, while the expression level of P62 was significantly decreased, in HepG2 cells under OGD condition. Over-expression of DCN significantly increased the expression level of Beclin1 and the LC3BI/LC3BII ratio, while no significant changes were observed in the P62 expression level, in HepG2 cells. Under the OGD condition, the apoptosis rate was also significantly decreased in DCN-transfected HepG2 cells. DCN protects HepG2 cells against OGD-induced injury, via regulating autophagy. These results might contribute to a better understanding of the roles of DCN and autophagy in hepatocellular carcinoma, and the potential treatment for the disease.