Impaired wound healing in mice deficient in a matricellular protein SPARC (osteonectin, BM-40)

Six drivers of aging identified among genes differentially expressed with age

Many studies have compared gene expression in young and old samples to gain insights on aging, the primary risk factor for most major chronic diseases. However, these studies only describe associations, failing to distinguish drivers of aging from compensatory geroprotective responses and incidental downstream effects. Here, we introduce a workflow to characterize the causal effects of differentially expressed genes on lifespan. First, we performed a meta-analysis of 25 gene expression datasets comprising samples of various tissues from healthy, untreated adult mammals (humans, dogs, and rodents) at two distinct ages. We ranked each gene according to the number of distinct datasets in which the gene was differentially expressed with age in a consistent direction. The top age-upregulated genes were TMEM176A, EFEMP1, CP, and HLA-A; the top age-downregulated genes were CA4, SIAH, SPARC, and UQCR10. Second, the effects of the top ranked genes on lifespan were measured by applying post-developmental RNA interference of the corresponding ortholog in the nematode C. elegans (two trials, with roughly 100 animals per genotype per trial). Out of 10 age-upregulated and 9 age-downregulated genes that were tested, two age-upregulated genes (csp-3/CASP1 and spch-2/RSRC1) and four age-downregulated genes (C42C1.8/DIRC2, ost-1/SPARC, fzy-1/CDC20, and cah-3/CA4) produced significant and reproducible lifespan extension. Notably, the data do not suggest that the direction of differential expression with age is predictive of the effect on lifespan. Our study provides novel insight into the relationship between differential gene expression and aging phenotypes, pilots an unbiased workflow that can be easily repeated and expanded, and pinpoints six genes with evolutionarily conserved, causal roles in the aging process for further study.

Combined analysis of single-cell sequencing and bulk transcriptome sequencing reveals new mechanisms for non-healing diabetic foot ulcers

Diabetic foot ulcers (DFUs) pose a significant challenge in diabetes care. Yet, a comprehensive understanding of the underlying biological disparities between healing and non-healing DFUs remains elusive. We conducted bioinformatics analysis of publicly available transcriptome sequencing data in an attempt to elucidate these differences. Our analysis encompassed differential analysis to unveil shifts in cell composition and gene expression profiles between non-healing and healing DFUs. Cell communication alterations were explored employing the Cellchat R package. Pseudotime analysis and cytoTRACE allowed us to dissect the heterogeneity within fibroblast subpopulations. Our findings unveiled disruptions in various cell types, localized low-grade inflammation, compromised systemic antigen processing and presentation, and extensive extracellular matrix signaling disarray in non-healing DFU patients. Some of these anomalies partially reverted in healing DFUs, particularly within the abnormal ECM-receptor signaling pathway. Furthermore, we distinguished distinct fibroblast subpopulations in non-healing and healing DFUs, each with unique biological functions. Healing-associated fibroblasts exhibited heightened extracellular matrix (ECM) remodeling and a robust wound healing response, while non-healing-associated fibroblasts showed signs of cellular senescence and complement activation, among other characteristics. This analysis offers profound insights into the wound healing microenvironment, identifies pivotal cell types for DFU healing promotion, and reveals potential therapeutic targets for DFU management.

circ-Amotl1 in extracellular vesicles derived from ADSCs improves wound healing by upregulating SPARC translation

Aim

This study aims to explore the mechanism of circ- AMOT-like protein 1 (Amotl1) in extracellular vesicles (Evs) derived from adipose-derived stromal cells (ADSCs) regulating SPARC translation in wound healing process.

Methods

The morphology, wound healing rate of the wounds and Ki67 positive rate in mouse wound healing models were assessed by H&E staining and immunohistochemistry (IHC). The binding of IGF2BP2 and SPARC was verified by RNA pull-down. Adipose-derived stromal cells (ADSCs) were isolated and verified. The Evs from ADSCs (ADSC-Evs) were analyzed.

Results

Overexpression of SPARC can promote the wound healing process in mouse models. IGF2BP2 can elevate SPARC expression to promote the proliferation and migration of HSFs. circ-Amotl1 in ADSC-Evs can increase SPARC expression by binding IGF2BP2 to promote the proliferation and migration of HSFs.

Conclusion

ADSC-Evs derived circ-Amotl1 can bind IGF2BP2 to increase SPARC expression and further promote wound healing process.

Caudal peduncle mineralized lesion resembling calcinosis circumscripta in a wels catfish Silurus glanis

This report presents an intriguing case of a mineralized lesion resembling calcinosis circumscripta observed in the caudal peduncle of a wels catfish, housed in a public aquarium in northern Italy. The investigation encompasses a comprehensive analysis of various aspects, including clinical presentation, diagnostic imaging, as well as gross and microscopic pathology, and immunohistochemistry. Histopathology, in particular, highlighted a severe focally extensive granulomatous reaction, confirmed by dense histiocytic inflammatory infiltrates and the massive presence of multinucleated foreign body type giant cells localized around lakes and aggregates of mineralized material. Moreover, the usefulness and limitations of immunohistochemistry and special stains in characterizing fish tissues and cell types are highlighted. Although reported in elasmobranchs and sturgeons, to our knowledge, this is the first description of calcinosis circumscripta in teleost fish and it offers valuable insights into the understanding of similar pathologies in aquatic organisms.

Matricellular proteins in cutaneous wound healing

Cutaneous wound healing is a complex process that encompasses alterations in all aspects of the skin including the extracellular matrix (ECM). ECM consist of large structural proteins such as collagens and elastin as well as smaller proteins with mainly regulative properties called matricellular proteins. Matricellular proteins bind to structural proteins and their functions include but are not limited to interaction with cell surface receptors, cytokines, or protease and evoking a cellular response. The signaling initiated by matricellular proteins modulates differentiation and proliferation of cells having an impact on the tissue regeneration. In this review we give an overview of the matricellular proteins that have been found to be involved in cutaneous wound healing and summarize the information known to date about their functions in this process.

SMOC2 promotes an epithelial-mesenchymal transition and a pro-metastatic phenotype in epithelial cells of renal cell carcinoma origin

Renal Cell Carcinoma (RCC) is the most common form of all renal cancer cases, and well-known for its highly aggressive metastatic behavior. SMOC2 is a recently described non-structural component of the extracellular matrix (ECM) that is highly expressed during tissue remodeling processes with emerging roles in cancers, yet its role in RCC remains elusive. Using gene expression profiles from patient samples, we identified SMOC2 as being significantly expressed in RCC tissue compared to normal renal tissue, which correlated with shorter RCC patient survival. Specifically, de novo protein synthesis of SMOC2 was shown to be much higher in the tubular epithelial cells of patients with biopsy-proven RCC. More importantly, we provide evidence of SMOC2 triggering kidney epithelial cells into an epithelial-to-mesenchymal transition (EMT), a phenotype known to promote metastasis. We found that SMOC2 induced mesenchymal-like morphology and activities in both RCC and non-RCC kidney epithelial cell lines. Mechanistically, treatment of RCC cell lines ACHN and 786-O with SMOC2 (recombinant and enforced expression) caused a significant increase in EMT-markers, -matrix production, -proliferation, and -migration, which were inhibited by targeting SMOC2 by siRNA. We further characterized SMOC2 activation of EMT to occur through the integrin β3, FAK and paxillin pathway. The proliferation and metastatic potential of SMOC2 overexpressing ACHN and 786-O cell lines were validated in vivo by their significantly higher tumor growth in kidneys and systemic dissemination into other organs when compared to their respective controls. In principle, understanding the impact that SMOC2 has on EMT may lead to more evidence-based treatments and biomarkers for RCC metastasis.

Scar prevention through topical delivery of gelatin-tyramine-siSPARC nanoplex loaded in dissolvable hyaluronic acid microneedle patch across skin barrier

Currently, there is no effective method to prevent the formation of hypertrophic scars and keloids, which can cause severe physical and psychological burdens to patients. Secreted protein acidic and cysteine-rich (SPARC) is involved in wound fibrosis by modulating fibroblast functions, causing excessive collagen deposition during wound healing. Thus, the reduction in SPARC gene expression after wounding can contribute to the downstream reduction in collagen production at the wound site and prevent scar formation. In this study, a dissolvable and biocompatible hyaluronic acid (HA) microneedle patch loaded with nanoplexes containing tyramine-modified gelatin and siRNA for SPARC (siSPARC/Gtn-Tyr) was investigated for topical scar prevention. Tyramine-modified gelatin (Gtn-Tyr) provides electrostatic protection and enhances cell internalization for siSPARC. In vitro studies using human dermal fibroblasts showed that both siSPARC/Gtn-Tyr nanoplexes and siSPARC/Gtn-Tyr-loaded microneedle patches can significantly reduce SPARC gene expression (P < 0.05) and do not cause discernable cytotoxic effects. Further studies using a mouse wound model demonstrate that the siSPARC/Gtn-Tyr-loaded microneedle patch can reduce collagen production during wound healing without triggering an immune response. When Gtn-Tyr-siSPARC is administered transdermally at the wound site, effective collagen reduction is achieved through silencing of the matricellular SPARC protein, thus promising the reduction of scar formation. Overall, the siSPARC/Gtn-Tyr loaded microneedle patch can potentially provide an effective transdermal anti-fibrotic treatment.

The effect of insulin and kruppel like factor 10 on osteoblasts in the dental implant osseointegration in diabetes mellitus patients

Diabetes mellitus, metabolic disease, is characterized by chronic hyperglycemia. Patients with diabetes mellitus are susceptible to infection and therefore have a higher prevalence and progression rate of periodontal disease. We aimed to study the effect of insulin and kruppel like factor 10 (KLF10) on osteoblasts proliferation and differentiation, and expression of bone metabolism-related molecules and related signaling pathway molecules of AKT serine/threonine kinase 1 (AKT) and nuclear factor kappa B subunit 1 (NF-κB) through in vitro experiments, which can provide theoretical basis for the dental implant osseointegration in diabetic patients. The osteoblasts (hFOB 1.19 cells) were subdivided into KLF10 gene over expression group, KLF10 gene knockdown group, and KLF10 gene knockdown + insulin treatment group. CCK-8 and ELISA were, respectively, used for analysis of cell proliferation and differentiation. In vitro experiments were applied to detect the mRNA and protein expression of bone metabolism-related molecules, respectively. GSE178351 dataset and GSE156993 dataset were utilized to explore the expression of KLF10 in periodontitis. In osteoblasts, insulin treatment increased the expression of KLF10. Insulin and KLF10 could reduce the proliferation and differentiation of osteoblasts. Knockdown of KLF10 could increase the expression of bone metabolism-related molecules and activate AKT and NF-κB pathways, whereas insulin reversed this effect. KLF10 was up-regulated in both patients with periodontitis and type 2 diabetes mellitus with periodontitis. It is assumed that knockdown of KLF10 in insulin resistance may promote osteoblasts differentiation and dental implant osseointegration in diabetic patients.

The interplay of fibroblasts, the extracellular matrix, and inflammation in scar formation

Various forms of fibrosis, comprising tissue thickening and scarring, are involved in 40% of deaths across the world. Since the discovery of scarless functional healing in fetuses prior to a certain stage of development, scientists have attempted to replicate scarless wound healing in adults with little success. While the extracellular matrix (ECM), fibroblasts, and inflammatory mediators have been historically investigated as separate branches of biology, it has become increasingly necessary to consider them as parts of a complex and tightly regulated system that becomes dysregulated in fibrosis. With this new paradigm, revisiting fetal scarless wound healing provides a unique opportunity to better understand how this highly regulated system operates mechanistically. In the following review, we navigate the four stages of wound healing (hemostasis, inflammation, repair, and remodeling) against the backdrop of adult versus fetal wound healing, while also exploring the relationships between the ECM, effector cells, and signaling molecules. We conclude by singling out recent findings that offer promising leads to alter the dynamics between the ECM, fibroblasts, and inflammation to promote scarless healing. One factor that promises to be significant is fibroblast heterogeneity and how certain fibroblast subpopulations might be predisposed to scarless healing. Altogether, reconsidering fetal wound healing by examining the interplay of the various factors contributing to fibrosis provides new research directions that will hopefully help us better understand and address fibroproliferative diseases, such as idiopathic pulmonary fibrosis, liver cirrhosis, systemic sclerosis, progressive kidney disease, and cardiovascular fibrosis.

Immunomodulation of Skin Repair: Cell-Based Therapeutic Strategies for Skin Replacement (A Comprehensive Review)

The immune system has a crucial role in skin wound healing and the application of specific cell-laden immunomodulating biomaterials emerged as a possible treatment option to drive skin tissue regeneration. Cell-laden tissue-engineered skin substitutes have the ability to activate immune pathways, even in the absence of other immune-stimulating signals. In particular, mesenchymal stem cells with their immunomodulatory properties can create a specific immune microenvironment to reduce inflammation, scarring, and support skin regeneration. This review presents an overview of current wound care techniques including skin tissue engineering and biomaterials as a novel and promising approach. We highlight the plasticity and different roles of immune cells, in particular macrophages during various stages of skin wound healing. These aspects are pivotal to promote the regeneration of nonhealing wounds such as ulcers in diabetic patients. We believe that a better understanding of the intrinsic immunomodulatory features of stem cells in implantable skin substitutes will lead to new translational opportunities. This, in turn, will improve skin tissue engineering and regenerative medicine applications.

Growth hormone/IGF-I-dependent signaling restores decreased expression of the myokine SPARC in aged skeletal muscle

Skeletal muscle exerts many beneficial effects on the human body including the contraction-dependent secretion of peptides termed myokines. We have recently connected the myokine secreted protein acidic and rich in cysteine (SPARC) to the formation of intramuscular adipose tissue (IMAT) in skeletal muscle from aged mice and humans. Here, we searched for inducers of SPARC in order to uncover novel treatment approaches for IMAT. Endurance exercise in mice as well as forskolin treatment in vitro only modestly activated SPARC levels. However, through pharmacological treatments in vitro, we identified IGF-I as a potent inducer of SPARC expression in muscle cells, likely through a direct activation of its promoter via phosphatidylinositol 4,5-bisphospate 3-kinase (PI3K)-dependent signaling. We employed two different mouse models of growth hormone (GH)/IGF-I deficiency to solidify our understanding of the relationship between IGF-I and SPARC in vivo. GH administration robustly increased intramuscular SPARC levels (3.5-fold) in GH releasing hormone receptor-deficient mice and restored low intramuscular SPARC expression in skeletal muscle from aged mice. Intramuscular glycerol injections induced higher levels of adipocyte markers (adiponectin, perilipin) in aged compared to young mice, which was not prevented by GH treatment. Our study provides a roadmap for the study of myokine regulation during aging and demonstrates that the GH/IGF-I axis is critical for SPARC expression in skeletal muscle. Although GH treatment did not prevent IMAT formation in the glycerol model, targeting SPARC by exercise or by activation of IGF-I signaling might offer a novel therapeutic strategy against IMAT formation during aging. KEY MESSAGES : IGF-I regulates the myokine SPARC in muscle cells directly at the promoter level. GH/IGF-I is able to restore the decreased SPARC levels in aged skeletal muscle. The glycerol model induces higher adipocyte markers in aged compared to young muscle. GH treatment does not prevent IMAT formation in the glycerol model.

Secreted Protein Acidic and Rich in Cysteine as a Molecular Physiological and Pathological Biomarker

Secreted protein acidic and rich in cysteine (SPARC) is expressed in diverse tissues and plays roles in various biological functions and processes. Increased serum levels of SPARC or its gene overexpression have been reported following numerous physiological and pathological changes including injuries, exercise, regeneration, obesity, cancer, and inflammation. Such expression pattern interrelation between these biological changes and the SPARC expression/secretion points to it as a biomarker. This property could lead to a variety of potential applications ranging from mechanistic studies and animal model validation to the clinical and therapeutic evaluation of both disease prognosis and pharmacological agents.

S100A8/A9 Enhances Immunomodulatory and Tissue-Repairing Properties of Human Amniotic Mesenchymal Stem Cells in Myocardial Ischemia-Reperfusion Injury

Paracrine factors of human mesenchymal stem cells (hMSCs) have the potential of preventing adverse cardiac remodeling after myocardial infarction (MI). S100A8 and S100A9 are calcium-binding proteins playing essential roles in the regulation of inflammation and fibrous tissue formation, and they might modulate the paracrine effect of hMSCs. We isolated human amniotic mesenchymal stem cells (hAMSCs) and examined the changes in the expression level of regulatory genes of inflammation and fibrosis after hAMSCs were treated with S100A8/A9. The anti-inflammatory and anti-fibrotic effects of hAMSCs pretreated with S100A8/A9 were shown to be superior to those of hAMSCs without S100A8/A9 pretreatment in the cardiomyocyte hypoxia/reoxygenation experiment. We established a murine myocardial ischemia/reperfusion model to compare the therapeutic effects of the conditioned medium of hAMSCs with or without S100A8/A9 pretreatment. We found the hearts administered with a conditioned medium of hAMSCs with S100A8/A9 pretreatment had better left ventricular systolic function on day 7, 14, and 28 after MI. These results suggest S100A8/A9 enhances the paracrine therapeutic effects of hAMSCs in aspects of anti-inflammation, anti-fibrosis, and cardiac function preservation after MI.

The Effect of SPARC on the Proliferation and Migration of Limbal Epithelial Stem Cells During the Corneal Epithelial Wound Healing

Secreted protein acidic and rich in cysteine (SPARC) shows a specific colocalization with limbal epithelial stem cells (LESCs) in vivo; however, the inherent relationship between SPARC and LESCs is still unclear. This study investigated the effects of SPARC on the maintenance of LESC stemness and corneal wound healing. To test the influence of different concentration of exogenous SPARC on the proliferation of LESCs, cell counting kit-8 assay and 5-ethynyl-2'-deoxyuridine staining were performed and the results indicated that 1 μg/mL SPARC was the optimum concentration for enhanced LESC proliferation. Compared with a control group, SPARC-treated group showed a higher expression of LESC-positive markers p63α, ABCG-2, and Bmi-1, and a lower level of differentiation marker cytokeratin-3 (CK3), thereby suggesting that SPARC could maintain LESC characteristic phenotype and suppress spontaneous epithelial differentiation in vitro. In vivo, exogenous SPARC accelerated the wound-healing process by both the enhancement of LESC proliferation and promoting the migration of the proliferating cells. However, the intact epithelium impaired this function of SPARC by contact inhibition.

Positive-charge tuned gelatin hydrogel-siSPARC injectable for siRNA anti-scarring therapy in post glaucoma filtration surgery

Small interfering RNA (siRNA) therapy is a promising epigenetic silencing strategy. However, its widespread adoption has been severely impeded by its ineffective delivery into the cellular environment. Here, a biocompatible injectable gelatin-based hydrogel with positive-charge tuned surface charge is presented as an effective platform for siRNA protection and delivery. We demonstrate a two-step synthesis of a gelatin-tyramine (Gtn-Tyr) hydrogel with simultaneous charge tunability and crosslinking ability. We discuss how different physiochemical properties of the hydrogel interact with siSPARC (siRNA for secreted protein, acidic and rich in cysteine), and study the positive-charge tuned gelatin hydrogel as an effective delivery platform for siSPARC in anti-fibrotic treatment. Through in vitro studies using mouse tenon fibroblasts, the positive-charge tuned Gtn-Tyr hydrogel shows sustained siSPARC cellular internalization and effective SPARC silencing with excellent biocompatibility. Similarly, the same hydrogel platform delivering siSPARC in an in vivo assessment employing a rabbit model shows an effective reduction in subconjunctival scarring in post glaucoma filtration surgery, and is non-cytotoxic compared to a commonly used anti-scarring agent, mitomycin-C. Overall, the current siRNA delivery strategy involving the positive-charge tuned gelatin hydrogel shows effective delivery of gene silencing siSPARC for anti-fibrotic treatment. The current charge tunable hydrogel delivery system is simple to fabricate and highly scalable. We believe this delivery platform has strong translational potential for effective siRNA delivery and epigenetic silencing therapy.

Exercise Training of Secreted Protein Acidic and Rich in Cysteine (Sparc) KO Mice Suggests That Exercise-Induced Muscle Phenotype Changes Are SPARC-Dependent

We previously identified secreted protein acidic and rich in cysteine (Sparc) as an exercise-induced gene in young and elderly individuals. Via this animal experiment, we aim to identify selected implications of SPARC mainly within the muscle in the contexts of exercise. Mice were divided into eight groups based on three variables (age, genotype and exercise): Old (O) or young (Y) × Sparc knock-out (KO) or wild-type (WT) × sedentary (Sed) or exercise (Ex). The exercised groups were trained for 12 weeks at the lactate threshold (LT) speed (including 4 weeks of adaptation period) and all mice were sacrificed afterwards. Body and selected tissues were weighed, and lactate levels in different conditions measured. Expression of skeletal muscle (SM) collagen type I alpha 1 chain (COL1A1) and mitochondrially encoded cytochrome c oxidase I (MT-CO1) in addition to SM strength (grip power) were also measured. Ageing increased the body and white adipose tissue (WAT) weights but decreased SM weight percentage (to body weight) and MT-CO1 expression (in WT). Exercise increased SM COL1A1 in WT mice and MT-CO1 expression, as well as weight percentage of the tibialis anterior muscle, and decreased WAT weight (trend). Compared to WT mice, Sparc KO mice had lower body, muscle and WAT weights, with a decrease in SM MT-CO1 and COL1A1 expression with no genotype effect on lactate levels in all our blood lactate measures. Sparc KO effects on body composition, adiposity and metabolic patterns are toward a reduced WAT and body weight, but with a negative metabolic and functional phenotype of SM. Whereas such negative effects on SM are worsened with ageing, they are relatively improved by exercise. Importantly, our data suggest that the exercise-induced changes in the SM phenotype, in terms of increased performance (metabolic, strength and development), including lactate-induced changes, are SPARC-dependent.

Smad‑binding decoy reduces extracellular matrix expression in human hypertrophic scar fibroblasts

The exact mechanisms underlying hypertrophic scarring is yet to be fully understood. However, excessive collagen deposition by fibroblasts has been demonstrated to result in hypertrophic scar formation, and collagen synthesis in dermal fibroblasts is regulated by the transforming growth factor-β1/Smad signaling pathway. In view of this, a Smad-binding decoy was designed and its effects on hypertrophic scar-derived human skin fibroblasts was evaluated. The results of the present study revealed that the Smad decoy attenuates the total amount of collagen, collagen I and Smad2/3 expression in scar fibroblasts. Data from RNA sequencing indicated that the Smad decoy induced more than 4-fold change in 178 genes, primarily associated with to the extracellular matrix, compared with the untreated control. In addition, results from quantitative real-time polymerase chain reaction further confirmed that the Smad decoy significantly attenuated the expression of extracellular matrix-related genes, including COL1A1, COL1A2 and COL3A1. Furthermore, the Smad decoy reduced transforming growth factor-β1-induced collagen deposition in scar fibroblasts. Data generated from the present study provide evidence supporting the use of the Smad decoy as a potential hypertrophic scar treatment.

Wound healing and fibrosis: a contrasting role for periostin in skin and the oral mucosa

Both skin and oral mucosa are characterized by the presence of keratinized epithelium in direct apposition to an underlying collagen-dense connective tissue. Despite significant overlap in structure and physiological function, skin and the oral mucosa exhibit significantly different healing profiles in response to injury. The oral mucosa has a propensity for rapid restoration of barrier function with minimal underlying fibrosis, but in contrast, skin is associated with slower healing and scar formation. Modulators of cell function, matricellular proteins have been shown to play significant roles in cutaneous healing, but their role in restoration of the oral mucosa is poorly defined. As will be discussed in this review, over the last 12 years our research group has been actively investigating the role of the profibrotic matricellular protein periostin in tissue homeostasis and fibrosis, as well as healing, in both skin and gingiva. In the skin, periostin is highly expressed in fibrotic scars and is upregulated during cutaneous wound repair, where it facilitates myofibroblast differentiation. In contrast, in gingival healing, periostin regulates extracellular matrix synthesis but does not appear to be associated with the transition of mesenchymal cells to a contractile phenotype. The significance of these findings will be discussed, with a focus on periostin as a potential therapeutic to augment healing of soft tissues or suppress fibrosis.

Secreted protein acidic and rich in cysteine and bioenergetics: Extracellular matrix, adipocytes remodeling and skeletal muscle metabolism

The extracellular matrix (ECM) remodeling plays important roles in both adipocytes shape/expansion remodeling and the skeletal muscle (SM) metabolism. Secreted protein acidic and rich in cysteine (SPARC) is expressed in divers tissues including adipose tissue (AT) and SM where it impacts a variety of remodeling as well as metabolic functions. SPARC, also known as osteonectin or BM-40, is a glycoprotein associated with the ECM. Numerous researches attempted to elucidate the implications of SPARC in these two key metabolic tissues under different conditions. Whereas SPARC deficiency tends to shape the remodeling of the adipocytes and the fat distribution, this deficiency decreases SM metabolic properties. On the other hand, SPARC seems to be an enhancer of the metabolism and a mediator of the exercise-induced adaptation in the SM and as well as an adipogenesis inhibitor. Some findings about the SPARC effects on AT and SM seem "contradictory" in terms of tissue development and energy profile therefore highlighting the mechanistic role of SPARC in both is a priority. Yet, within this review, we expose selected researches and compare the results. We conclude with explanations to "reconcile" the different observations, hypothesize the feedback and regulatory character of SPARC and put its roles within the energetic and structural maps of both adipocytes and myocytes in homeostasis and in situations such as obesity or exercise. These properties explain the modifications and the remodeling seen in AT and SM undergoing adaptive changes (obesity, exercise, etc.) and represent a starting point for precise therapeutic targeting of SPARC-related pathways is conditions such as obesity, sarcopenia and diabetes.

Impact of Fibroblast-Derived SPARC on Invasiveness of Colorectal Cancer Cells

Secreted protein acidic and rich in cysteine (SPARC) is a matricellular protein modulating cell-matrix interactions and was found up-regulated in tumor stroma. To explore the effect of high stromal SPARC on colorectal cancer (CRC) cell behavior and clinical outcome, this study determined SPARC expression in patients suffering from stage II and III CRC using a publicly available mRNA data set and immunohistochemistry of tissue microarray sections. Moreover, in vitro co-culture models using CRC cell lines together with colon-associated fibroblasts were established to determine the effect of fibroblast-derived SPARC on cancer cells. In 466 patient samples, high SPARC mRNA was associated with a shorter disease-free survival. In 99 patients of the tissue microarray cohort, high stromal SPARC in the primary tumor was an independent predictor of shorter survival in patients with relapse (27 cases; HR = 4574, p = 0.004). In CRC cell lines, SPARC suppressed phosphorylation of focal adhesion kinase and stimulated cell migration. Colon-associated fibroblasts increased migration velocity by 30% and doubled track-length in SPARC-dependent manner. In a 3D co-culture system, fibroblast-derived SPARC enhanced tumor cell invasion. Taken together, stromal SPARC had a pro-metastatic impact in vitro and was a characteristic of aggressive tumors with poor prognosis in CRC patients.

Targeted therapy for the post-operative conjunctiva: SPARC silencing reduces collagen deposition

BACKGROUND

To develop targeted antifibrotic therapy for glaucoma filtration surgery; this study determines the effectiveness of small interfering RNA (siRNA) to reduce in vivo secreted protein acidic and rich in cysteine (SPARC) expression using the mouse model of conjunctival scarring.

METHODS

Experimental surgery was performed as described for the mouse model of conjunctival scarring. Scrambled (siScram) or Sparc (siSparc) siRNAs, loaded on layer-by-layer (LbL) nanoparticles, were injected into the conjunctiva immediately after surgery. Expression of Sparc, Col1a1, Fn1 and Mmp14 was measured by real-time PCR and immunoblotting on days 7 and 14 postsurgery. Live imaging of the operated eyes was performed using slit lamp, anterior segment-optical coherence tomography and confocal microscopy. Tissue pathology was evaluated by histochemical and immunofluorescent analyses of operated conjunctival cryosections. Tissue apoptosis was quantitated by annexin V assay. RESULTS : siSparc, delivered via expanded LbL nanoparticles, significantly inhibited Sparc transcription in both day 7 (2.04-fold) and day 14 (1.39-fold) treated tissues. Sparc suppression on day 7 was associated with a significant reduction of Col1a1 (2.52-fold), Fn1 (2.89-fold) and Mmp14 (2.23-fold) mRNAs. At the protein level, both SPARC and collagen 1A1 (COL1A1) were significantly reduced at both time points with siSparc treatment. Nanoparticles were visualised within cell-like structures by confocal microscopy, while overt tissue response or apoptosis was not observed. CONCLUSIONS : SPARC targeted therapy effectively reduced both SPARC and collagen production in the operated mouse conjunctiva. This proof-of-concept study suggests that targeted treatment of fibrosis in glaucoma surgery is safe and feasible, with the potential to extend to a range of potential genes associated with fibrosis.

A Novel S100A8/A9 Induced Fingerprint of Mesenchymal Stem Cells associated with Enhanced Wound Healing

We here investigated whether the unique capacity of mesenchymal stem cells (MSCs) to re-establish tissue homeostasis depends on their potential to sense danger associated molecular pattern (DAMP) and to mount an adaptive response in the interest of tissue repair. Unexpectedly, after injection of MSCs which had been pretreated with the calcium-binding DAMP protein S100A8/A9 into murine full-thickness wounds, we observed a significant acceleration of healing even exceeding that of non-treated MSCs. This correlates with a fundamental reprogramming of the transcriptome in S100A8/A9 treated MSCs as deduced from RNA-seq analysis and its validation. A network of genes involved in proteolysis, macrophage phagocytosis, and inflammation control profoundly contribute to the clean-up of the wound site. In parallel, miR582-5p and genes boosting energy and encoding specific extracellular matrix proteins are reminiscent of scar-reduced tissue repair. This unprecedented finding holds substantial promise to refine current MSC-based therapies for difficult-to-treat wounds and fibrotic conditions.

Proteomic profiling identifies markers for inflammation-related tumor-fibroblast interaction

Background

Cancer associated fibroblasts are activated in the tumor microenvironment and contribute to tumor progression, angiogenesis, extracellular matrix remodeling, and inflammation.

Methods

To identify proteins characteristic for fibroblasts in colorectal cancer we used liquid chromatography-tandem mass spectrometry to derive protein abundance from whole-tissue homogenates of human colorectal cancer/normal mucosa pairs. Alterations of protein levels were determined by two-sided t test with greater than threefold difference and an FDR of < 0.05. Public available datasets were used to predict proteins of stromal origin and link protein with mRNA regulation. Immunohistochemistry confirmed the localization of selected proteins.

Results

We identified a set of 24 proteins associated with inflammation, matrix organization, TGFβ receptor signaling and angiogenesis mainly originating from the stroma. Most prominent were increased abundance of SerpinB5 in the parenchyme and latent transforming growth factor β-binding protein, thrombospondin-B2, and secreted protein acidic-and-cysteine-rich in the stroma. Extracellular matrix remodeling involved collagens type VIII, XII, XIV, and VI as well as lysyl-oxidase-2. In silico analysis of mRNA levels demonstrated altered expression in the tumor and the adjacent normal tissue as compared to mucosa of healthy individuals indicating that inflammatory activation affected the surrounding tissue. Immunohistochemistry of 26 tumor specimen confirmed upregulation of SerpinB5, thrombospondin B2 and secreted protein acidic-and-cysteine-rich.

Conclusions

This study demonstrates the feasibility of detecting tumor- and compartment-specific protein-signatures that are functionally meaningful by proteomic profiling of whole-tissue extracts together with mining of RNA expression datasets. The results provide the basis for further exploration of inflammation-related stromal markers in larger patient cohorts and experimental models.

Common extracellular matrix regulation of myeloid cell activity in the bone marrow and tumor microenvironments

The complex interaction between cells undergoing transformation and the various stromal and immunological cell components of the tumor microenvironment (TME) crucially influences cancer progression and diversification, as well as endowing clinical and prognostic significance. The immunosuppression characterizing the TME depends on the recruitment and activation of different cell types including regulatory T cells, myeloid-derived suppressor cells, and tumor-associated macrophages. Less considered is the non-cellular component of the TME. Here, we focus on the extracellular matrix (ECM) regulatory activities that, within the TME, actively contribute to many aspects of tumor progression, acting on both tumor and immune cells. Particularly, ECM-mediated regulation of tumor-associated immunosuppression occurs through the modulation of myeloid cell expansion, localization, and functional activities. Such regulation is not limited to the TME but occurs also within the bone marrow, wherein matricellular proteins contribute to the maintenance of specialized hematopoietic stem cell niches thereby regulating their homeostasis as well as the generation and expansion of myeloid cells under both physiological and pathological conditions. Highlighting the commonalities among ECM-myeloid cell interactions in bone marrow and TME, in this review we present a picture in which myeloid cells might sense and respond to ECM modifications, providing different ECM-myeloid cell interfaces that may be useful to define prognostic groups and to tailor therapeutic interventions.

The wound healing, chronic fibrosis, and cancer progression triad

For decades tumors have been recognized as "wounds that do not heal." Besides the commonalities that tumors and wounded tissues share, the process of wound healing also portrays similar characteristics with chronic fibrosis. In this review, we suggest a tight interrelationship, which is governed as a concurrence of cellular and microenvironmental reactivity among wound healing, chronic fibrosis, and cancer development/progression (i.e., the WHFC triad). It is clear that the same cell types, as well as soluble and matrix elements that drive wound healing (including regeneration) via distinct signaling pathways, also fuel chronic fibrosis and tumor progression. Hence, here we review the relationship between fibrosis and cancer through the lens of wound healing.

Discovery of an uncovered region in fibrin clots and its clinical significance

Despite the pathological importance of fibrin clot formation, little is known about the structure of these clots because X-ray and nuclear magnetic resonance (NMR) analyses are not applicable to insoluble proteins. In contrast to previously reported anti-fibrin monoclonal antibodies (mAbs), our anti-fibrin clot mAb (clone 102–10) recognises an uncovered region that is exposed only when a fibrin clot forms. The epitope of the 102–10 mAb was mapped to a hydrophobic region on the Bβ chain that interacted closely with a counterpart region on the γ chain in a soluble state. New anti-Bβ and anti-γ mAbs specific to peptides lining the discovered region appeared to bind exclusively to fibrin clots. Furthermore, the radiolabelled 102–10 mAb selectively accumulated in mouse spontaneous tumours, and immunohistochemistry using this mAb revealed greater fibrin deposition in World Health Organization (WHO) grade 4 glioma than in lower-grade gliomas. Because erosive tumours are apt to cause micro-haemorrhages, even early asymptomatic tumours detected with a radiolabelled 102-10 mAb may be aggressively malignant.

Transcriptomic profiling permits the identification of pollutant sources and effects in ambient water samples

Contaminant exposure is one possible contributor to population declines of endangered fish species in the Sacramento-San Joaquin Estuary, California, including the endangered delta smelt (Hypomesus transpacificus). Herein we investigated transcriptional responses in larval delta smelt resulting from exposure to water samples collected at the Department of Water Resources Field Station at Hood, a site of concern, situated upstream of known delta smelt habitat and spawning sites and downstream of the Sacramento Regional Wastewater Treatment Plant (SRWTP). Microarray assessments indicate impacts on energy metabolism, DNA repair mechanisms and RNA processing, the immune system, development and muscle function. Transcription responses of fish exposed to water samples from Hood were compared with exposures to 9% effluent samples from SRWTP, water from the Sacramento River at Garcia Bend (SRGB), upstream of the effluent discharge, and SRGB water spiked with 2mg/L total ammonium (9% effluent equivalent). Results indicate that transcriptomic profiles from Hood are similar to 9% SRWTP effluent and ammonium spiked SRGB water, but significantly different from SRGB. SRGB samples however were also significantly different from laboratory controls, suggesting that SRWTP effluent is not solely responsible for the responses determined at Hood, that ammonium exposure likely enhances the effect of multiple-contaminant exposures, and that the observed mortality at Hood is due to the combination of both effluent discharge and contaminants arising from upstream of the tested sites.

Secreted protein acidic and rich in cysteine (SPARC) exacerbates colonic inflammatory symptoms in dextran sodium sulphate-induced murine colitis

BACKGROUND

Secreted Protein Acidic and Rich in Cysteine (SPARC) is expressed during tissue repair and regulates cellular proliferation, migration and cytokine expression. The aim was to determine if SPARC modifies intestinal inflammation.

METHODS

Wild-type (WT) and SPARC-null (KO) mice received 3% dextran sodium sulphate (DSS) for 7 days. Inflammation was assessed endoscopically, clinically and histologically. IL-1β, IL-4, IL-5, IL-6, IL-10, IL-13, IL-17A, IL-12/IL23p40, TNF-α, IFN-γ, RANTES, MCP-1, MIP-1α, MIP-1β, MIG and TGF-β1 levels were measured by ELISA and cytometric bead array. Inflammatory cells were characterised by CD68, Ly6G, F4/80 and CD11b immunofluorescence staining and regulatory T cells from spleen and mesenteric lymph nodes were assessed by flow cytometry.

RESULTS

KO mice had less weight loss and diarrhoea with less endoscopic and histological inflammation than WT animals. By day 35, all (n = 13) KO animals completely resolved the inflammation compared to 7 of 14 WT mice (p<0.01). Compared to WTs, KO animals at day 7 had less IL1β (p= 0.025) and MIG (p = 0.031) with higher TGFβ1 (p = 0.017) expression and a greater percentage of FoxP3+ regulatory T cells in the spleen and draining lymph nodes of KO animals (p<0.01). KO mice also had fewer CD68+ and F4/80+ macrophages, Ly6G+ neutrophils and CD11b+ cells infiltrating the inflamed colon.

CONCLUSIONS

Compared to WT, SPARC KO mice had less inflammation with fewer inflammatory cells and more regulatory T cells. Together, with increased TGF-β1 levels, this could aid in the more rapid resolution of inflammation and restoration of the intestinal mucosa suggesting that the presence of SPARC increases intestinal inflammation.

Human hair follicle dermal sheath and papilla cells support keratinocyte growth in monolayer coculture

Traditional skin grafting techniques are effective but limited methods of skin replacement. Autologous transplantation of rapidly cultured keratinocytes is successful for epidermal regeneration, but the current gold-standard technique requires mouse fibroblast feeders and serum-rich media, with serum-free systems and dermal fibroblast (DF) feeders performing relatively poorly. Here, we investigated the capacity of human hair follicle dermal cells to act as alternative supports for keratinocyte growth. Dermal papilla (DP) dermal sheath (DS), DF and 3T3 cells were used as inactivated feeder cells for human keratinocyte coculture. Under conditions favouring dermal cells, proliferation of keratinocytes in the presence of either DS or DP cells was significantly enhanced compared with DF cells, at levels comparable to keratinocytes cultured under gold-standard conditions. Secreted protein acidic and rich in cysteine (SPARC) expression increased DS and DP cells relative to DFs; however, further experiments did not demonstrate a role in keratinocyte support.

SPARC-like 1 (SC1) is a diversely expressed and developmentally regulated matricellular protein that does not compensate for the absence of SPARC in the CNS

SPARC-like 1 (SC1) is a member of the SPARC family of matricellular proteins that has been implicated in the regulation of processes such as cell migration, proliferation, and differentiation. Here we show that SC1 exhibits remarkably diverse and dynamic expression in the developing and adult nervous system. During development, SC1 localizes to radial glia and pial-derived structures, including the vasculature, choroid plexus, and pial membranes. SC1 is not downregulated in postnatal development, but its expression shifts to distinct time windows in subtypes of glia and neurons, including astrocytes, large projection neurons, Bergmann glia, Schwann cells, and ganglionic satellite cells. In addition, SC1 expression levels and patterns are not altered in the SPARC null mouse, suggesting that SC1 does not compensate for the absence of SPARC. We conclude that SC1 and SPARC may share significant homology, but are likely to have distinct but complementary roles in nervous system development.

SPARC regulates microgliosis and functional recovery following cortical ischemia

Secreted protein acidic rich in cysteine (SPARC) is a matricellular protein that modulates the activity of growth factors, cytokines, and extracellular matrix to play multiple roles in tissue development and repair, such as cellular adhesion, migration, and proliferation. Throughout the CNS, SPARC is highly localized in mature ramified microglia, but its role in microglia--in development or during response to disease or injury--is not understood. In the postnatal brain, immature amoeboid myeloid precursors only induce SPARC expression after they cease proliferation and migration, and transform into mature, ramified resting microglia. SPARC null/CX3CR1-GFP reporter mice reveal that SPARC regulates the distribution and branching of mature microglia, with significant differences between cortical gray and white matter in both controls and SPARC nulls. Following ischemic and excitotoxic lesion, reactive, hypertrophic microglia rapidly downregulate and release SPARC at the lesion, concomitant with reactive, hypertrophic perilesion astrocytes upregulating SPARC. After photothrombotic stroke in the forelimb sensorimotor cortex, SPARC nulls demonstrate enhanced microgliosis in and around the lesion site, which accompanies significantly enhanced functional recovery by 32 d after lesion. Microglia from SPARC nulls also intrinsically proliferate at a greater rate in vitro--an enhanced effect that can be rescued by the addition of exogenous SPARC. SPARC is thus a novel regulator of microglial proliferation and structure, and, in addition to regulating glioma progression, may play an important role in differently regulating the gray and white matter microglial responses to CNS lesion--and modulating behavioral recovery--after injury.

Prospective potency of TGF-β1 on maintenance and regeneration of periodontal tissue

Periodontal ligament (PDL) tissue, central in the periodontium, plays crucial roles in sustaining tooth in the bone socket. Irreparable damages of this tissue provoke tooth loss, causing a decreased quality of life. The question arises as to how PDL tissue is maintained or how the lost PDL tissue can be regenerated. Stem cells included in PDL tissue (PDLSCs) are widely accepted to have the potential to maintain or regenerate the periodontium, but PDLSCs are very few in number. In recent studies, undifferentiated clonal human PDL cell lines were developed to elucidate the applicable potentials of PDLSCs for the periodontal regenerative medicine based on cell-based tissue engineering. In addition, it has been suggested that transforming growth factor-beta 1 is an eligible factor for the maintenance and regeneration of PDL tissue.

In vitro analyses of the anti-fibrotic effect of SPARC silencing in human Tenon's fibroblasts: comparisons with mitomycin C

Failure of glaucoma filtration surgery (GFS) is commonly attributed to scarring at the surgical site. The human Tenon’s fibroblasts (HTFs) are considered the major cell type contributing to the fibrotic response. We previously showed that SPARC (secreted protein, acidic, rich in cysteine) knockout mice had improved surgical success in a murine model of GFS. To understand the mechanisms of SPARC deficiency in delaying subconjunctival fibrosis, we used the gene silencing approach to reduce SPARC expression in HTFs and examined parameters important for wound repair and fibrosis. Mitomycin C-treated HTFs were used for comparison. We demonstrate that SPARC-silenced HTFs showed normal proliferation and negligible cellular necrosis but were impaired in motility and collagen gel contraction. The expression of pro-fibrotic genes including collagen I, MMP-2, MMP-9, MMP-14, IL-8, MCP-1 and TGF-β₂ were also reduced. Importantly, TGF-β₂ failed to induce significant collagen I and fibronectin expressions in the SPARC-silenced HTFs. Together, these data demonstrate that SPARC knockdown in HTFs modulates fibroblast functions important for wound fibrosis and is therefore a promising strategy in the development of anti-scarring therapeutics.

Fetal ventriculomegaly due to familial submicroscopic terminal 6q deletions

Submicroscopic terminal 6q deletions are rare. We report on two familial submicroscopic terminal 6q deletions ascertained because of prenatally detected isolated ventriculomegaly and further delineate the variable prenatal and postnatal phenotype. We review published cases of <5 Mb terminal 6q deletions.

Human umbilical cord perivascular cells improve rat hepatocyte function ex vivo

Hepatocyte functionality and survival decrease rapidly in culture, and both can be improved using bone marrow-derived mesenchymal stromal cells (MSCs). We have previously described an alternative, more plentiful source of MSCs coming from the perivascular area of the umbilical cord, human umbilical cord perivascular cells (HUCPVCs). Our objective was therefore to ascertain whether HUCPVCs could serve as hepatocyte stromal cells ex vivo. For this purpose, rat hepatocytes were cocultured in contact with HUCPVCs (contact coculture). Also, HUCPVCs were cocultured separated from hepatocytes with a semipermeable membrane (noncontact coculture) to assess soluble factor interactions. Next, an HUCPVC-conditioned medium (CM) was used to investigate the possibility of HUCPVC-free support, while flash-frozen HUCPVCs were employed to investigate the effects of nonsoluble interactions. In all experiments, medium samples were taken daily to assess the production of albumin. Also, at certain days, the levels of cytochrome P450 (CYP) activity and urea secretion were tested. RNA extraction was performed at the end of experiments. Our results show that HUCPVCs in contact and noncontact cocultures with hepatocytes improve albumin gene expression and secretion compared to monoculture. Flash-frozen HUCPVCs had a late improvement in albumin secretion, while CM improved it for a short period. Ureagenesis maintenance was improved by contact coculture and flash-frozen HUCPVCs. CYP activity was significantly increased in the presence of flash-frozen HUCPVCs and in noncontact cocultures. We conclude that HUCPVCs can act as stromal cells for rat hepatocytes, and that soluble and nonsoluble factors induce differential effects on hepatocytes.

Matricellular proteins in cardiac adaptation and disease

The term matricellular proteins describes a family of structurally unrelated extracellular macromolecules that, unlike structural matrix proteins, do not play a primary role in tissue architecture, but are induced following injury and modulate cell-cell and cell-matrix interactions. When released to the matrix, matricellular proteins associate with growth factors, cytokines, and other bioactive effectors and bind to cell surface receptors transducing signaling cascades. Matricellular proteins are upregulated in the injured and remodeling heart and play an important role in regulation of inflammatory, reparative, fibrotic and angiogenic pathways. Thrombospondin (TSP)-1, -2, and -4 as well as tenascin-C and -X secreted protein acidic and rich in cysteine (SPARC), osteopontin, periostin, and members of the CCN family (including CCN1 and CCN2/connective tissue growth factor) are involved in a variety of cardiac pathophysiological conditions, including myocardial infarction, cardiac hypertrophy and fibrosis, aging-associated myocardial remodeling, myocarditis, diabetic cardiomyopathy, and valvular disease. This review discusses the properties and characteristics of the matricellular proteins and presents our current knowledge on their role in cardiac adaptation and disease. Understanding the role of matricellular proteins in myocardial pathophysiology and identification of the functional domains responsible for their actions may lead to design of peptides with therapeutic potential for patients with heart disease.

Differential Expression of SPARC in Intestinal-type Gastric Cancer Correlates with Tumor Progression and Nodal Spread

AIMS

Nodal spread is the single most important prognostic factor of survival in gastric cancer patients. In this study, genes that were upregulated in the lymph node metastases of gastric cancer were identified and may serve as putative novel therapeutic target.

METHODS

Complementary DNA (cDNA) microarray analysis and quantitative real-time polymerase chain reaction of primary gastric carcinomas and matched lymph node metastasis were carried out. Immunohistochemistry with anti-SPARC antibodies was performed on large tissue sections of 40 cases with primary gastric carcinoma (20 diffuse, 20 intestinal) and the corresponding lymph node metastases, as well as on tissue microarrays of 152 gastric cancer cases.

RESULTS

A cDNA microarray identified SPARC as being upregulated in primary gastric carcinoma tissue and the corresponding lymph node metastasis compared with the nonneoplastic mucosa. SPARC was expressed in fibroblasts and, occasionally, in tumor cells. However, the level of immunoreactivity was particularly strong in stromal cells surrounding the tumor. The level of expression of SPARC, determined by immunohistochemistry, correlated in intestinal-type gastric cancer with the local tumor growth, nodal spread, and tumor stage according to the International Union Against Cancer.

CONCLUSIONS

Our study provides transcriptional and translational evidence for the differential expression of SPARC in gastric cancer tissue. On the basis of our observations and those made by others, we hypothesize that SPARC is a promising novel target for the treatment of gastric cancer.

Differential Expression of SPARC in Intestinal-type Gastric Cancer Correlates with Tumor Progression and Nodal Spread

AIMS

Nodal spread is the single most important prognostic factor of survival in gastric cancer patients. In this study, genes that were upregulated in the lymph node metastases of gastric cancer were identified and may serve as putative novel therapeutic target.

METHODS

Complementary DNA (cDNA) microarray analysis and quantitative real-time polymerase chain reaction of primary gastric carcinomas and matched lymph node metastasis were carried out. Immunohistochemistry with anti-SPARC antibodies was performed on large tissue sections of 40 cases with primary gastric carcinoma (20 diffuse, 20 intestinal) and the corresponding lymph node metastases, as well as on tissue microarrays of 152 gastric cancer cases.

RESULTS

A cDNA microarray identified SPARC as being upregulated in primary gastric carcinoma tissue and the corresponding lymph node metastasis compared with the nonneoplastic mucosa. SPARC was expressed in fibroblasts and, occasionally, in tumor cells. However, the level of immunoreactivity was particularly strong in stromal cells surrounding the tumor. The level of expression of SPARC, determined by immunohistochemistry, correlated in intestinal-type gastric cancer with the local tumor growth, nodal spread, and tumor stage according to the International Union Against Cancer.

CONCLUSIONS

Our study provides transcriptional and translational evidence for the differential expression of SPARC in gastric cancer tissue. On the basis of our observations and those made by others, we hypothesize that SPARC is a promising novel target for the treatment of gastric cancer.

TP53INP1 decreases pancreatic cancer cell migration by regulating SPARC expression

Tumor protein 53 induced nuclear protein 1 (TP53INP1) is a p53 target gene that induces cell growth arrest and apoptosis by modulating p53 transcriptional activity. TP53INP1 interacts physically with p53 and is a major player in the p53-driven oxidative stress response. Previously, we demonstrated that TP53INP1 is downregulated in an early stage of pancreatic cancerogenesis and when restored is able to suppress pancreatic tumor development. TP53INP1 downregulation in pancreas is associated with an oncogenic microRNA miR-155. In the present work, we studied the effects of TP53INP1 on cell migration. We found that TP53INP1 inactivation correlates with increased cell migration both in vivo and in vitro. The impact of TP53INP1 expression on cell migration was studied in different cellular contexts: mouse embryonic fibroblast and different pancreatic cancer cell lines. Its expression decreases cell migration by the transcriptional downregulation of secreted protein acidic and rich in cysteine (SPARC). SPARC is a matrix cellular protein, which governs diverse cellular functions and has a pivotal role in regulating cell-matrix interactions, cellular proliferation and migration. SPARC was also showed to be upregulated in normal pancreas and in pancreatic intraepithelial neoplasia lesions in a pancreatic adenocarcinoma mouse model only in the TP53INP1-deficient animals. This novel TP53INP1 activity on the regulation of SPARC expression could explain in part its tumor suppressor function in pancreatic adenocarcinoma by modulating cellular spreading during the metastatic process.

SPARC deficiency results in improved surgical survival in a novel mouse model of glaucoma filtration surgery

Glaucoma is a disease frequently associated with elevated intraocular pressure that can be alleviated by filtration surgery. However, the post-operative subconjunctival scarring response which blocks filtration efficiency is a major hurdle to the achievement of long-term surgical success. Current application of anti-proliferatives to modulate the scarring response is not ideal as these often give rise to sight-threatening complications. SPARC (secreted protein, acidic and rich in cysteine) is a matricellular protein involved in extracellular matrix (ECM) production and organization. In this study, we investigated post-operative surgical wound survival in an experimental glaucoma filtration model in SPARC-null mice. Loss of SPARC resulted in a marked (87.5%) surgical wound survival rate compared to 0% in wild-type (WT) counterparts. The larger SPARC-null wounds implied that aqueous filtration through the subconjunctival space was more efficient in comparison to WT wounds. The pronounced increase in both surgical survival and filtration efficiency was associated with a less collagenous ECM, smaller collagen fibril diameter, and a loosely-organized subconjunctival matrix in the SPARC-null wounds. In contrast, WT wounds exhibited a densely packed collagenous ECM with no evidence of filtration capacity. Immunolocalization assays confirmed the accumulation of ECM proteins in the WT but not in the SPARC-null wounds. The observations in vivo were corroborated by complementary data performed on WT and SPARC-null conjunctival fibroblasts in vitro. These findings indicate that depletion of SPARC bestows an inherent change in post-operative ECM remodeling to favor wound maintenance. The evidence presented in this report is strongly supportive for the targeting of SPARC to increase the success of glaucoma filtration surgery.

Synergistic effects of osteonectin and NGF in promoting survival and neurite outgrowth of superior cervical ganglion neurons

Schwann cells (SCs) play a major role in the successful regeneration of peripheral nerves regeneration. Here we examined the effects of osteonectin (ON), a major factor secreted by SCs, on survival and neuritogenesis of mouse superior cervical ganglion (SCG) neurons. SC conditioned medium (SCCM) not only promoted the survival and neuritogenesis of SCG neurons at a level comparable to nerve growth factor (NGF) but also doubled the neurite length of NGF-treated SCG neurons. SCCM neuritogenic effects were not blocked by the tyrosine kinase receptor (Trk) inhibitor K252a demonstrating that these are not due solely to classical neurotrophic factors. Anti-ON neutralizing antibody diminished the SCCM-induced survival and neuritogenesis significantly. In the presence of K252a, the SCCM neuritogenic effects were blocked completely by anti-ON which suggests synergistic effects of ON with Trk-mediated growth factors. ON alone increased the survival and neurite outgrowth of SCG neurons significantly at high density cultures. ON at low concentration acts synergistically with NGF which induced maximum survival and neurite outgrowth (>50% increase). However, ON at high concentration was detrimental to survival (64% decrease) and neurite outgrowth (87% decrease) even in the presence of NGF. The well documented counter-adhesive effect of ON may account for this observation. Nevertheless, the growth promoting effects of ON became more pronounced as the cell density increased which suggests a possible interaction of ON with growth factors secreted by SCG neurons (autocrine or paracrine effects). Taken together, our study indicates that ON plays important roles in nervous system repair through its synergistic effects with growth factors.

Periostin localizes to cells in normal skin, but is associated with the extracellular matrix during wound repair

Epidermal tissue repair represents a complex series of temporal and dynamic events resulting in wound closure. Matricellular proteins, not normally expressed in quiescent adult tissues, play a pivotal role in wound repair and associated extracellular matrix remodeling by modulating the adhesion, migration, intracellular signaling, and gene expression of inflammatory cells, pericytes, fibroblasts and keratinocytes. Several matricellular proteins show temporal expression during dermal wound repair, but the expression pattern of the recently identified matricellular protein, periostin, has not yet been characterized. The primary aim of this study was to assess whether periostin protein is present in healthy human skin or in pathological remodeling (Nevus). The second aim was to determine if periostin is expressed during dermal wound repair. Using immunohistochemistry, periostin reactivity was detected in the keratinocytes, basal lamina, and dermal fibroblasts in healthy human skin. In pathological nevus samples, periostin was present in the extracellular matrix. In excisional wounds in mice, periostin protein was first detected in the granulation tissue at day 3, with levels peaking at day 7. Periostin protein co-localized with α-smooth muscle actin-positive cells and keratinocytes, but not CD68 positive inflammatory cells. We conclude that periostin is normally expressed at the cellular level in human and murine skin, but additionally becomes extracellular during tissue remodeling. Periostin may represent a new therapeutic target for modulating the wound repair process.

Rho isoforms have distinct and specific functions in the process of epithelial to mesenchymal transition in renal proximal tubular cells

Epithelial to mesenchymal transition (EMT) is involved in embryological development, cancerous metastatic spread and organ fibrosis, including the kidney. This process is largely driven by transforming growth factor-beta and recent evidence has implicated Rho as a key intracellular signalling molecule. In this study we have used RNA interference to silence the genetically distinct Rho (A, B and C) isoforms to define their individual functions in human kidney epithelial cells undergoing EMT. We demonstrate that the downregulation of the epithelial cell marker E-cadherin is dependent upon the Rho effector, Rho-kinase. However, silencing RhoA or RhoC expression also results in E-cadherin loss, though each by different mechanisms. Loss of RhoA leads to an upregulation of Snail1 and a reduction in the transcription of E-cadherin whereas loss of RhoC upregulates its breakdown via proteasomal degradation. During EMT, the upregulation of alpha-smooth muscle actin can be blocked by inhibiting the expression of RhoA, but not by that of RhoB or RhoC. This effect is independent of Rho-kinase activity. RhoC is the isoform solely responsible for stress fibre formation and inhibiting its expression reduces EMT-induced migration by 50%. RhoB appears to play a role in cell survival as inhibiting its expression leads to >300% increase in cell apoptosis and a relocalization of focal adhesion kinase. We conclude that Rho is a key signalling molecule in the process of EMT but that each isoform has a distinct and specific role.

Inflammation-dependent expression of SPARC during development of chronic pancreatitis in WBN/Kob rats and a microarray gene expression analysis

The pathophysiology of human chronic pancreatitis is not well understood and difficult to follow on a molecular basis. Therefore, we used a rat model [Wistar-Bonn/Kobori (WBN/Kob)] that exhibits spontaneous chronic inflammation and fibrosis in the pancreas. Using microarrays we compared gene expression patterns in the pancreas during development of inflammation and fibrosis of WBN/Kob rats with age-matched healthy Wistar rats. The extracellular matrix protein SPARC (secreted protein, acidic, and rich in cysteines) and other transcripts of inflammatory genes were quantified by real-time PCR, and some were localized by immunohistochemistry. When pancreatic inflammation becomes obvious at the age of 16 wk, several hundred genes are increased between 3- and 50-fold in WBN/Kob rats compared with healthy Wistar rats. Proteins produced by acinar cells and characteristic for inflammation, e.g., pancreatitis-associated protein, are highly upregulated. Other proteins, derived from infiltrating inflammatory cells and from activated stellate cells (fibrosis) such as collagens and fibronectins are also significantly upregulated. SPARC was localized to acinar cells where it increased in the vicinity of inflammatory foci. However, acinar expression of SPARC was lost during destruction of acinar cells. In human pancreatic specimens with chronic pancreatitis, SPARC exhibited a similar expression profile. During chronic inflammation and fibrosis in the WBN/Kob rat, inflammatory genes, growth factors, and structural genes exhibit a high increase of expression. A temporal profile including pre- and postinflammatory phases indicates a concurrent activation of inflammatory and fibrotic changes. Inflammation dependent expression of SPARC appears to be lost during acinar-to-duct metaplasia both in rat and human pancreas.