Thrombospondin-1 plays a profibrotic and pro-inflammatory role during ureteric obstruction

Activation of SIRT3 by Tanshinone IIA ameliorates renal fibrosis by suppressing the TGF-β/TSP-1 pathway and attenuating oxidative stress

Although doxorubicin (DOX) is a common chemotherapeutic drug, the serious nephrotoxicity caused by DOX-induced renal fibrosis remains a considerable clinical problem. Tanshinone IIA (Tan IIA), a compound extracted from Salvia miltiorrhiza, has been reported to have an anti-fibrotic effect. Therefore, this study investigated the molecular pathway whereby Tan IIA protects the kidneys from DOX administration. DOX (3 mg/kg body weight) was intraperitoneally administered every 3 d for a total of 7 injections (cumulative dose of 21 mg/kg) to induce nephrotoxicity. Then, Tan IIA (5 or 10 mg/kg/d) was administered by intraperitoneal injection for 28 d. In an in vitro study, 293 T cells were cultured and treated with DOX and Tan IIA for 24 h. Tan IIA reduced the blood urea nitrogen levels elevated by DOX while increasing superoxide dismutase activity, down-regulating reactive oxygen species, ameliorating renal-tubule thickening, and rescuing mitochondrial morphology. Additionally, Tan IIA reduced the renal collagen deposition, increased ATP production and complex-I activity, down-regulated transforming growth factor-β1 (TGF-β1) and thrombospondin-1 (TSP-1), and up-regulated sirtuin 3 (SIRT3). Tan IIA significantly increased cell viability. Additionally, RNA interference was employed to silence the expression of SIRT3, which eliminated the effect of Tan IIA in suppressing the expression of TGF-β1 and TSP-1. In conclusion, Tan IIA ameliorated DOX-induced nephrotoxicity by attenuating oxidative injury and fibrosis. The Tan IIA-induced rescue of mitochondrial morphology and function while alleviating renal fibrosis may be associated with the activation of SIRT3 to suppress the TGF-β/TSP-1 pathway.

Role of TSP-1 and its receptor ITGB3 in the renal tubulointerstitial injury of focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS), a common cause of primary glomerulonephritis, has a poor prognosis and is pathologically featured by tubulointerstitial injury. Thrombospondin-1 (TSP-1) is an extracellular matrix protein that acts in combination with different receptors in the kidney. Here, we analyzed the tubular expression of TSP-1 and its receptor integrin β3 (ITGB3) in FSGS. Previously the renal interstitial chip analysis of FSGS patients with tubular interstitial injury showed that the expression of TSP-1 and ITGB3 were upregulated. We found that the expression of TSP-1 and ITGB3 increased in the tubular cells of FSGS patients. The plasma level of TSP-1 increased and was correlated to the degree of tubulointerstitial lesions in FSGS patients. TSP-1/ITGB3 signaling induced renal tubular injury in HK-2 cells exposure to bovine serum albumin and the adriamycin (ADR)-induced nephropathy model. THBS1 KO ameliorated tubular injury and renal fibrosis in ADR-treated mice. THBS1 knockdown decreased the expression of KIM-1 and caspase 3 in the HK-2 cells treated with bovine serum albumin, while THBS1 overexpression could induce tubular injury. In vivo, we identified cyclo-RGDfK as an agent to block the binding of TSP-1 to ITGB3. Cyclo-RGDfK treatment could alleviate ADR-induced renal tubular injury and interstitial fibrosis in mice. Moreover, TSP-1 and ITGB3 were colocalized in tubular cells of FSGS patients and ADR-treated mice. Taken together, our data showed that TSP-1/ITGB3 signaling contributed to the development of renal tubulointerstitial injury in FSGS, potentially identifying a new therapeutic target for FSGS.

Thrombospondin 1 enhances systemic inflammation and disease severity in acute-on-chronic liver failure

BACKGROUND

The key role of thrombospondin 1 (THBS1) in the pathogenesis of acute-on-chronic liver failure (ACLF) is unclear. Here, we present a transcriptome approach to evaluate THBS1 as a potential biomarker in ACLF disease pathogenesis.

METHODS

Biobanked peripheral blood mononuclear cells (PBMCs) from 330 subjects with hepatitis B virus (HBV)-related etiologies, including HBV-ACLF, liver cirrhosis (LC), and chronic hepatitis B (CHB), and normal controls (NC) randomly selected from the Chinese Group on the Study of Severe Hepatitis B (COSSH) prospective multicenter cohort underwent transcriptome analyses (ACLF = 20; LC = 10; CHB = 10; NC = 15); the findings were externally validated in participants from COSSH cohort, an ACLF rat model and hepatocyte-specific THBS1 knockout mice.

RESULTS

THBS1 was the top significantly differentially expressed gene in the PBMC transcriptome, with the most significant upregulation in ACLF, and quantitative polymerase chain reaction (ACLF = 110; LC = 60; CHB = 60; NC = 45) was used to verify that THBS1 expression corresponded to ACLF disease severity outcome, including inflammation and hepatocellular apoptosis. THBS1 showed good predictive ability for ACLF short-term mortality, with an area under the receiver operating characteristic curve (AUROC) of 0.8438 and 0.7778 at 28 and 90 days, respectively. Enzyme-linked immunosorbent assay validation of the plasma THBS1 using an expanded COSSH cohort subjects (ACLF = 198; LC = 50; CHB = 50; NC = 50) showed significant correlation between THBS1 with ALT and γ-GT (P = 0.01), and offered a similarly good prognostication predictive ability (AUROC = 0.7445 and 0.7175) at 28 and 90 days, respectively. ACLF patients with high-risk short-term mortality were identified based on plasma THBS1 optimal cut-off value (< 28 µg/ml). External validation in ACLF rat serum and livers confirmed the functional association between THBS1, the immune response and hepatocellular apoptosis. Hepatocyte-specific THBS1 knockout improved mouse survival, significantly repressed major inflammatory cytokines, enhanced the expression of several anti-inflammatory mediators and impeded hepatocellular apoptosis.

CONCLUSIONS

THBS1 might be an ACLF disease development-related biomarker, promoting inflammatory responses and hepatocellular apoptosis, that could provide clinicians with a new molecular target for improving diagnostic and therapeutic strategies.

Integrin β1-rich extracellular vesicles of kidney recruit Fn1+ macrophages to aggravate ischemia-reperfusion-induced inflammation

Ischemia-reperfusion injury-induced (IRI-induced) acute kidney injury is accompanied by mononuclear phagocyte (MP) invasion and inflammation. However, systematic analysis of extracellular vesicle-carried (EV-carried) proteins mediating intercellular crosstalk in the IRI microenvironment is still lacking. Multiomics analysis combining single-cell RNA-Seq data of kidney and protein profiling of kidney-EV was used to elucidate the intercellular communication between proximal tubular cells (PTs) and MP. Targeted adhesion and migration of various MPs were caused by the secretion of multiple chemokines as well as integrin β1-rich EV by ischemic-damaged PTs after IRI. These recruited MPs, especially Fn1+ macrophagocyte, amplified the surviving PT's inflammatory response by secreting the inflammatory factors TNF-α, MCP-1, and thrombospondin 1 (THBS-1), which could interact with integrin β1 to promote more MP adhesion and interact with surviving PT to further promote the secretion of IL-1β. However, GW4869 reduced MP infiltration and maintained a moderate inflammatory level likely by blocking EV secretion. Our findings establish the molecular bases by which chemokines and kidney-EV mediate PT-MP crosstalk in early IRI and provide insights into systematic intercellular communication.

A pilot study on the relationship between thrombospondin-1 (THBS1) and transforming growth factor beta1 (TGFβ1) in the bovine placenta during early mid-pregnancy as well as parturition with normally released and retained placenta

During pregnancy, it is necessary to create appropriate conditions for the development of the placenta and the fetus. However, during parturition, the placenta must be separated and subsequently removed as soon as possible to not expose the female to the possibility of infection. In this study, the relationship between thrombospondin-1 (THBS1) and transforming growth factor beta1 (TGFβ1) concentrations was described during bovine pregnancy (second, fourth, and sixth months; n = 3/each month), at normal parturition (NR) and parturition with fetal membrane retention (R). The presence of THBS1 and TGFβ1 was confirmed in bovine placental tissues of both maternal and fetal parts. Enzyme-linked immunosorbent assay showed statistically significant differences (p < 0.05) in THBS1 concentrations (pg/mg protein) between examined parturient samples (maternal part: 5.76 ± 1.61 in R vs. 2.26 ± 1.58 in NR; fetal part: 2.62 ± 1.94 in R vs. 1.70 ± 0.23 in NR). TGFβ1 concentrations (pg/mg protein) were significantly lower (p < 0.05) in the retained fetal membranes compared to the released fetal membranes in the maternal part of the placenta (26.22 ± 7.53 in NR vs. 17.80 ± 5.01 in R). The participation of THBS1 in the activation of TGFβ1 in parturient bovine placental tissues leading to the normal release of fetal membranes may be suggested.

Thrombospondin1 antagonist peptide treatment attenuates obesity-associated chronic inflammation and metabolic disorders in a diet-induced obese mouse model

Thrombospondin1 (TSP1) is a multifunctional matricellular protein. Previously, we demonstrated that TSP1 plays a pivotal role in obesity-related inflammation and insulin resistance (IR) by modulating macrophage accumulation and activation in adipose tissue. Moreover, in our in vitro studies, a CD36-derived peptide, functioning as a TSP1 antagonist, effectively inhibited TSP1-induced proinflammatory macrophage activation. However, whether this CD36 peptide can inhibit obesity-induced inflammation and IR in vivo is unknown and determined in this study in a high fat diet-induced obese mouse model (DIO). CD36 peptide or control peptide was intraperitoneally administered into the established obese mice triweekly for 6 weeks. We found that CD36 peptide treatment didn't affect obesity or weight gain but significantly reduced proinflammatory cytokine production systemically and in visceral fat tissue. Adipose tissue exhibited fewer crown-like structures and reduced macrophage infiltration. CD36 peptide treatment also attenuated the proinflammatory phenotype of bone marrow derived macrophages from obese mice. Furthermore, CD36 peptide treatment improved glucose tolerance and insulin sensitivity, and mitigated obesity-related fatty liver disease and kidney damage. Collectively, this study suggests that the CD36 peptide, as a TSP1 antagonist, shows promise as a novel therapeutic approach for managing obesity-related metabolic disorders.

Apabetalone Downregulates Fibrotic, Inflammatory and Calcific Processes in Renal Mesangial Cells and Patients with Renal Impairment

Epigenetic mechanisms are implicated in transcriptional programs driving chronic kidney disease (CKD). Apabetalone is an orally available inhibitor of bromodomain and extraterminal (BET) proteins, which are epigenetic readers that modulate gene expression. In the phase 3 BETonMACE trial, apabetalone reduced risk of major adverse cardiac events (MACE) by 50% in the CKD subpopulation, indicating favorable effects along the kidney-heart axis. Activation of human renal mesangial cells (HRMCs) to a contractile phenotype that overproduces extracellular matrix (ECM) and inflammatory cytokines, and promotes calcification, frequently accompanies CKD to drive pathology. Here, we show apabetalone downregulated HRMC activation with TGF-β1 stimulation by suppressing TGF-β1-induced α-smooth muscle actin (α-SMA) expression, α-SMA assembly into stress fibers, enhanced contraction, collagen overproduction, and expression of key drivers of fibrosis, inflammation, or calcification including thrombospondin, fibronectin, periostin, SPARC, interleukin 6, and alkaline phosphatase. Lipopolysaccharide-stimulated expression of inflammatory genes IL6, IL1B, and PTGS2 was also suppressed. Transcriptomics confirmed apabetalone affected gene sets of ECM remodeling and integrins. Clinical translation of in vitro results was indicated in CKD patients where a single dose of apabetalone reduced plasma levels of key pro-fibrotic and inflammatory markers, and indicated inhibition of TGF-β1 signaling. While plasma proteins cannot be traced to the kidney alone, anti-fibrotic and anti-inflammatory effects of apabetalone identified in this study are consistent with the observed decrease in cardiovascular risk in CKD patients.

Anti-fibrotic effect of tocotrienols for bladder dysfunction due to partial bladder outlet obstruction

PURPOSE

To investigate potential beneficial effects of tocotrienols which have been suggested to inhibit hypoxia-inducible factor (HIF) pathway, on partial bladder outlet obstruction (PBOO)-induced bladder pathology.

MATERIALS AND METHODS

PBOO was surgically created in juvenile male mice. Sham-operated mice were used as controls. Animals received daily oral administration of either tocotrienols (T₃) or soybean oil (SBO, vehicle) from day 0 to 13 post-surgery. Bladder function was examined in vivo by void spot assay. At 2 weeks post-surgery, the bladders were subjected to physiological evaluation of detrusor contractility in vitro using bladder strips, histology by H&amp;E staining and collagen imaging, and gene expression analyses by quantitative PCR.

RESULTS

A significant increase in the number of small voids was observed after 1 week of PBOO compared to the control groups. At 2 weeks post-surgery, PBOO+SBO mice showed a further increase in the number of small voids, which was not observed in PBOO+T₃ group. PBOO-induced decrease in detrusor contractility was similar between two treatments. PBOO induced bladder hypertrophy to the same degree in both SBO and T₃ treatment groups, however, fibrosis in the bladder was significantly less prominent in the T₃ group than the SBO group following PBOO (1.8- vs. 3.0-fold increase in collagen content compared to the control). Enhanced levels of HIF target genes in the bladders were observed in PBOO+SBO group, but not in PBOO+T₃ group compared to the control.

CONCLUSIONS

Oral tocotrienol treatment reduced the progression of urinary frequency and bladder fibrosis by suppressing HIF pathways triggered by PBOO.

Circ_0047339 promotes the activation of fibroblasts and affects the development of urethral stricture by targeting the miR-4691-5p/TSP-1 axis

Urethral stricture is related to scar tissue fibrosis, but its pathogenesis is still unclear. This study aims to explore the regulatory mechanism of circular RNA (circRNA) in the occurrence and development of urethral stricture. CircRNA microarray was employed to analyze circRNA expression profiles between human urethral scar tissue and normal urethral tissue. The results of circRNA microarray showed that there were 296 differentially expressed genes between urethral scar tissue and normal urethral tissue. The enrichment analysis of Kyoto encyclopedia of genes and genomes showed that these circRNAs were significantly correlated with ECM–receptor interaction. The first nine differentially expressed circRNA were selected to predict the circRNA–miRNA network. RT-qPCR results showed that circ_0047339 was upregulated considerably in urethral scar tissue. Urethral scar fibroblasts were isolated from human urethral scar tissue and cultured in vitro. After silencing circ_0047339, the proliferation of urethral scar cells decreased significantly, and the expressions of Collagen I (COL-1) and α-smooth muscle actin (α-SMA) also reduced. As a competing endogenous RNA, circ_0047339 could increase the expression of TSP-1 by competitively binding miR-4691-5p. In addition, miR-4691-5p mimic transfection could inhibit the proliferation of urethral scar fibroblasts and the presentation of thrombospondin-1 (TSP-1), α-SMA and COL-1, while circ_0047339 overexpression eliminated this inhibition. Our results showed that circ_0047339 might promote the growth and fibrosis of urethral scar fibroblasts through miR-4691-5p/TSP-1 axis, thus promoting the development of urethral stricture.

Sestrin2 remedies podocyte injury via orchestrating TSP-1/TGF-β1/Smad3 axis in diabetic kidney disease

Sestrin2 is identified as a stress-induced protein and could functionate in many aspects. In our study, we investigated the latent impact of Sestrin2 on podocyte injury and its molecular mechanism in vivo and in vitro in diabetic kidney disease (DKD). Sestrin2 was low-expressed in renal biopsies from individuals with DKD, the glomeruli from diabetic mice, and mouse podocytes exposed to high glucose (HG). Sestrin2 overexpression ameliorated HG-induced phenotypic alterations, apoptosis, and oxidative stress in conditionally immortalized mouse podocytes and modulated the activity of Thrombospondin-1 (TSP-1)/transforming growth factor (TGF-β1)/Smad3 pathway in podocytes. Moreover, TSP-1 inhibitor LSKL or TGF-β blocker Pirfenidone arrested podocyte injury induced by HG. Streptozotocin (STZ) was employed to render equivalent diabetes in B6-TgN (CMV-Sestrin2) (TgN) and wild-type (WT) control mice. Sestrin2 alleviated increased levels of 24-h urinary protein, blood urea nitrogen, serum creatinine and triglyceride, and urine 8-OHdG in diabetic mice. Podocyte phenotypic alterations, increased expression of apoptosis-associated proteins and podocyte loss were observed in WT but not in diabetic TgN mice, as well as oxidative stress. Additionally, TSP-1/TGF-β1/Smad3 signaling pathway was also suppressed in glomeruli of diabetic TgN mice. Thus, Sestrin2 mitigates podocyte injury in DKD via orchestrating TSP-1/TGF-β1/Smad3 pathway, underlining Sestrin2 as a promising therapeutic target for DKD.

The fibrogenic niche in kidney fibrosis: components and mechanisms

Kidney fibrosis, characterized by excessive deposition of extracellular matrix (ECM) that leads to tissue scarring, is the final common outcome of a wide variety of chronic kidney diseases. Rather than being distributed uniformly across the kidney parenchyma, renal fibrotic lesions initiate at certain focal sites in which the fibrogenic niche is formed in a spatially confined fashion. This niche provides a unique tissue microenvironment that is orchestrated by a specialized ECM network consisting of de novo-induced matricellular proteins. Other structural elements of the fibrogenic niche include kidney resident and infiltrated inflammatory cells, extracellular vesicles, soluble factors and metabolites. ECM proteins in the fibrogenic niche recruit soluble factors including WNTs and transforming growth factor-β from the extracellular milieu, creating a distinctive profibrotic microenvironment. Studies using decellularized ECM scaffolds from fibrotic kidneys show that the fibrogenic niche autonomously promotes fibroblast proliferation, tubular injury, macrophage activation and endothelial cell depletion, pathological features that recapitulate key events in the pathogenesis of chronic kidney disease. The concept of the fibrogenic niche represents a paradigm shift in understanding of the mechanism of kidney fibrosis that could lead to the development of non-invasive biomarkers and novel therapies not only for chronic kidney disease, but also for fibrotic diseases of other organs.

Fatty kidney: A possible future for chronic kidney disease research

BACKGROUND

Metabolic syndrome is a growing twenty-first century pandemic associated with multiple clinical comorbidities ranging from cardiovascular diseases, non-alcoholic fatty liver disease and polycystic ovary syndrome to kidney dysfunction. A novel area of research investigates the concept of fatty kidney in the pathogenesis of chronic kidney disease, especially in patients with diabetes mellitus or metabolic syndrome.

AIM

To review the most updated literature on fatty kidney and provide future research, diagnostic and therapeutic perspectives on a disease increasingly affecting the contemporary world.

MATERIALS AND METHOD

We performed an extensive literature search through three databases including Embase (Elsevier) and the Cochrane Central Register of Controlled Trials (Wiley) and PubMed/Medline Web of Science in November 2021 by using the following terms and their combinations: 'fatty kidney', 'ectopic fat', 'chronic kidney disease', 'cardiovascular event', 'cardio-metabolic risk', 'albuminuria' and 'metabolic syndrome'. Each study has been individually assessed by the authors.

RESULTS

Oxidative stress and inflammation, Klotho deficiency, endoplasmic reticulum stress, mitochondrial dysfunction and disruption of cellular energy balance appear to be the main pathophysiological mechanisms leading to tissue damage following fat accumulation. Despite the lack of large-scale comprehensive studies in this novel field of research, current clinical trials demonstrate fatty kidney as an independent risk factor for the development of chronic kidney disease and cardiovascular events.

CONCLUSION

The requirement for future studies investigating the pathophysiology, clinical outcomes and therapeutics of fatty kidney is clear.

CD47 Binding on Vascular Endothelial Cells Inhibits IL-17-Mediated Leukocyte Adhesion

To address the conflicting role of thrombospondin (TSP)-1 reported in acute and chronic pathologies, this study investigated the role of TSP-1 in regulating leukocyte recruitment and regulation of VCAM-1 expression using mouse models of uveitis. The spontaneously increased VCAM-1 expression and leukocyte adhesion in retinas of TSP-1-deficient mice suggested a TSP-1-mediated regulation of VCAM-1 expression. In a chronic uveitis model, induced by immunizing wild-type mice with specific interphotoreceptor retinoid-binding protein (IRBP) peptide, topically applied TSP-1-derived CD47-binding peptide significantly reduced the clinical disease course and retinal leukocyte adhesion as compared to the control peptide-treated group. In contrast, in LPS-mediated acute uveitis, TSP-1 deficiency significantly reduced the retinal leukocyte adhesion. The results of our in vitro study, using vascular endothelial cell (EC) cultures, demonstrate that unlike TNF-α, VCAM-1 expression induced by IL-17 is associated with a reduced expression of endogenous TSP-1. Such reduced endogenous TSP-1 expression in IL-17-stimulated ECs helps limit the CD36-mediated increased VCAM-1 expression, while favoring CD47-mediated inhibition of VCAM-1 expression and leukocyte adhesion. Thus, our study identifies TSP-1:CD47 interaction as a molecular pathway that modulates IL-17-mediated VCAM-1 expression, contributing to its anti-inflammatory effect in chronic inflammatory conditions.

Expression of human CD47 in pig glomeruli prevents proteinuria and prolongs graft survival following pig-to-baboon xenotransplantation

BACKGROUND

Nephrotic syndrome is a common complication of pig-to-baboon kidney xenotransplantation (KXTx) that adversely affects outcomes. We have reported that upregulation of CD80 and down-regulation of SMPDL-3b in glomeruli have an important role in the development of proteinuria following pig-to-baboon KXTx. Recently we found induced expression of human CD47 (hCD47) on endothelial cells and podocytes isolated from hCD47 transgenic (Tg) swine markedly reduced phagocytosis by baboon and human macrophages. These observations led us to hypothesize that transplanting hCD47 Tg porcine kidneys could overcome the incompatibility of the porcine CD47-baboon SIRPα interspecies ligand-receptor interaction and prevent the development of proteinuria following KXTx.

METHODS

Ten baboons received pig kidneys with vascularized thymic grafts (n = 8) or intra-bone bone marrow transplants (n = 2). Baboons were divided into three groups (A, B, and C) based on the transgenic expression of hCD47 in GalT-KO pigs. Baboons in Group A received kidney grafts with expression of hCD47 restricted to glomerular cells (n = 2). Baboons in Group B received kidney grafts with high expression of hCD47 on both glomerular and tubular cells of the kidneys (n = 4). Baboons in Group C received kidney grafts with low/no glomerular expression of hCD47, and high expression of hCD47 on renal tubular cells (n = 4).

RESULTS

Consistent with this hypothesis, GalT-KO/hCD47 kidney grafts with high expression of hCD47 on glomerular cells developed minimal proteinuria. However, high hCD47 expression in all renal cells including renal tubular cells induced an apparent destructive inflammatory response associated with upregulated thrombospondin-1. This response could be avoided by a short course of weekly anti-IL6R antibody administration, resulting in prolonged survival without proteinuria (mean 170.5 days from 47.8 days).

CONCLUSION

Data showed that transgenic expression of hCD47 on glomerular cells in the GalT-KO donor kidneys can prevent xenograft nephropathy, a significant barrier for therapeutic applications of xenotransplantation. The ability to prevent nephrotic syndrome following KXTx overcomes a critical barrier for future clinical applications of KXTx.

Association between renin-angiotensin system and chronic lung allograft dysfunction

Chronic lung allograft dysfunction (CLAD) is the major cause of death after lung transplantation. Angiotensin II (AngII), the main effector of the renin-angiotensin (RA) system, elicits fibrosis in both kidney and lung. We identified 6 AngII-regulated proteins (RHOB, BST1, LYPA1, GLNA, TSP1, LAMB1) increased in urine of patients with kidney allograft fibrosis. We hypothesized that RA system is active in CLAD and that AngII-regulated proteins are increased in bronchoalveolar lavage fluid (BAL) of CLAD patients.We performed immunostaining of AngII receptors (AGTR1 and AGTR2) and TSP1/GLNA in 10 CLAD lungs and 5 controls. Using mass spectrometry, we quantified peptides corresponding to AngII-regulated proteins in BAL of 40 lung transplant recipients (CLAD, stable and acute lung allograft dysfunction (ALAD)). Machine learning algorithms were developed to predict CLAD based on BAL peptide concentrations.Immunostaining demonstrated significantly more AGTR1+ cells in CLAD versus control lungs (p=0.02). TSP1 and GLNA immunostaining positively correlated with the degree of lung fibrosis (R²=0.42 and 0.57, respectively). In BAL, we noted a trend toward higher concentrations of AngII-regulated peptides in patients with CLAD at the time of bronchoscopy, and significantly higher concentrations of BST1, GLNA and RHOB peptides in patients that developed CLAD at follow-up (p<0.05). Support vector machine classifier discriminated CLAD from stable and ALAD patients at the time of bronchoscopy with AUC 0.86, and accurately predicted subsequent CLAD development (AUC 0.97).Proteins involved in the RA system are increased in CLAD lung and BAL. AngII-regulated peptides measured in BAL may accurately identify patients with CLAD and predict subsequent CLAD development.

Comparative Analysis of Whey Proteins in Human Milk Using a Data-Independent Acquisition Proteomics Approach during the Lactation Period

Human milk (HM) is the primary source of nutrients and bioactive components that supports the growth and development of infants. However, the proteins present in human milk may change depending on the period of lactation. In this light, the objective of the present study was to evaluate the effect of lactation period on HM utilizing a data-independent acquisition (DIA) approach to identify the differences in HM whey protein proteomes. As part of the study, whey proteins of January, February, and June in human milk were studied. The results identified a total of 1563 proteins in HM whey proteins of which 114 groups were subunits of differentially expressed proteins as revealed by cluster analysis. Protein expression was observed to be affected by the period of lactation with expression levels of plasminogen, thrombospondin-1, and tenascin higher during January, keratin, type I cytoskeletal 9 highest in February, and transcobalamin-1 highest in June. The results of this study contribute to expand our understanding of the human whey proteome but also provide strong evidence for the nutritional difference of HM during different lactation periods.

Transcriptome profiling of cells exposed to particular and intense electromagnetic radiation emitted by the "SG-III" prototype laser facility

The experiment of inertial confinement fusion by the "ShengGuang (SG)-III" prototype laser facility is a transient and extreme reaction process within several nanoseconds, which could form a very complicated and intense electromagnetic field around the target chamber of the facility and may lead to harmful effect on people around. In particular, the biological effects arising from such specific environment field could hardly be ignored and have never been investigated yet, and thus, we reported on the investigation of the biological effects of radiation on HaCat cells and PC12 cells to preliminarily assess the biological safety of the target range of the "SG-III" prototype laser facility. The viability revealed that the damage of cells was dose-dependent. Then we compared the transcriptomes of exposed and unexposed PC12 cells by RNA-Seq analysis based on Illumina Novaseq 6000 platform and found that most significantly differentially expressed genes with corresponding Gene Ontology terms and pathways were strongly involved in proliferation, transformation, necrosis, inflammation response, apoptosis and DNA damage. Furthermore, we find increase in the levels of several proteins responsible for cell-cycle regulation and tumor suppression, suggesting that pathways or mechanisms regarding DNA damage repair was are quickly activated. It was found that "SG-III" prototype radiation could induce DNA damage and promote apoptotic necrosis.

Effects of High Glucose and Lipotoxicity on Diabetic Podocytes

Glomerular podocytes are highly differentiated cells that cover glomerular capillaries from the outside and have a characteristic morphology with numerous foot processes. The formation of slit membranes between the foot processes serves as a final filtration barrier for urine filtration from the blood. Podocyte damage causes disruption of the slit membrane, subsequent proteinuria and finally glomerulosclerosis, which is a common pathway in various types of chronic kidney disease (CKD). In recent years, there has been an increase in diabetes, due to rapid lifestyle changes, which is the main cause of CKD. Therefore, understanding the effect of diabetic status on podocytes is of great importance to establish a strategy for preventing CKD progression. In this review, we summarize altered glucose and lipid metabolism in diabetic podocytes and also discuss the reversibility of the changes in podocyte phenotype.

Tanshinone IIA Ameliorates Streptozotocin-Induced Diabetic Nephropathy, Partly by Attenuating PERK Pathway-Induced Fibrosis

Purpose

Tanshinone IIA (Tan IIA), a compound extracted from Salvia miltiorrhiza, can improve type II diabetes, while the molecular mechanisms underlying Tan IIA-mediated protective effects in diabetic nephropathy are unclear. This study explored the protective actions of Tan IIA on renal tissues in streptozotocin (STZ)-induced diabetic nephropathy.

Materials and Methods

Tan IIA (2, 4, 8 mg/kg/day) was daily administered to STZ-treated rats by intraperitoneal injection for 42 days. The morphologic pathology was evaluated by hematoxylin-eosin and Masson’s trichrome staining, and transmission electron microscopy. The protein expression levels in renal tissues were evaluated by Western blotting and immunohistochemistry; the mRNA expression level was determined by quantitative real-time PCR.

Results

Tan IIA at 2 and 4 mg/kg attenuated the increase in the levels of uric acid and blood urea nitrogen and restored the reduction in the superoxide dismutase activity in the serum of the diabetic rats. Tan IIA at 2 and 4 mg/kg, but not 8 mg/kg, ameliorated the thickening of renal tubule in the diabetic rats; Tan IIA at 2 and 4 and 8 mg/kg attenuated the thickening of glomerular basement membrane and the collagen deposition in the renal tissues of the diabetic rats. Tan IIA treatment at 2, 4, 8 mg/kg decreased the expression levels of transforming growth factor-beta1, TSP-1, Grp78 and CHOP in the diabetic rats. Tan IIA at 2 and 4 and 8 mg/kg attenuated the increase in the protein levels of p-PERK, p-elf2α and ATF-4 from the renal tissues of diabetic rats, while the protein level of AFT-6 and the mRNA expression levels of XBP-1t, XBP-1s and p58IPK in the renal tissues were not affected by STZ or Tan IIA treatment.

Conclusion

Tan IIA-mediated protective effects on the STZ-induced diabetic nephropathy may be associated with the reduced endoplasmic reticulum stress via attenuating PERK signaling activities.

Immunomodulatory Role of the Extracellular Matrix Within the Liver Disease Microenvironment

Chronic liver disease when accompanied by underlying fibrosis, is characterized by an accumulation of extracellular matrix (ECM) proteins and chronic inflammation. Although traditionally considered as a passive and largely architectural structure, the ECM is now being recognized as a source of potent damage-associated molecular pattern (DAMP)s with immune-active peptides and domains. In parallel, the ECM anchors a range of cytokines, chemokines and growth factors, all of which are capable of modulating immune responses. A growing body of evidence shows that ECM proteins themselves are capable of modulating immunity either directly via ligation with immune cell receptors including integrins and TLRs, or indirectly through release of immunoactive molecules such as cytokines which are stored within the ECM structure. Notably, ECM deposition and remodeling during injury and fibrosis can result in release or formation of ECM-DAMPs within the tissue, which can promote local inflammatory immune response and chemotactic immune cell recruitment and inflammation. It is well described that the ECM and immune response are interlinked and mutually participate in driving fibrosis, although their precise interactions in the context of chronic liver disease are poorly understood. This review aims to describe the known pro-/anti-inflammatory and fibrogenic properties of ECM proteins and DAMPs, with particular reference to the immunomodulatory properties of the ECM in the context of chronic liver disease. Finally, we discuss the importance of developing novel biotechnological platforms based on decellularized ECM-scaffolds, which provide opportunities to directly explore liver ECM-immune cell interactions in greater detail.

Peritubular Capillary Rarefaction: An Underappreciated Regulator of CKD Progression

Peritubular capillary (PTC) rarefaction is commonly detected in chronic kidney disease (CKD) such as hypertensive nephrosclerosis and diabetic nephropathy. Moreover, PTC rarefaction prominently correlates with impaired kidney function and predicts the future development of end-stage renal disease in patients with CKD. However, it is still underappreciated that PTC rarefaction is a pivotal regulator of CKD progression, primarily because the molecular mechanisms of PTC rarefaction have not been well-elucidated. In addition to the established mechanisms (reduced proangiogenic factors and increased anti-angiogenic factors), recent studies discovered significant contribution of the following elements to PTC loss: (1) prompt susceptibility of PTC to injury, (2) impaired proliferation of PTC, (3) apoptosis/senescence of PTC, and (4) pericyte detachment from PTC. Mainly based on the recent and novel findings in basic research and clinical study, this review describes the roles of the above-mentioned elements in PTC loss and focuses on the major factors regulating PTC angiogenesis, the assessment of PTC rarefaction and its surrogate markers, and an overview of the possible therapeutic agents to mitigate PTC rarefaction during CKD progression. PTC rarefaction is not only a prominent histological characteristic of CKD but also a central driving force of CKD progression.

Bioinformatic analysis reveals hub genes and pathways that promote melanoma metastasis

BACKGROUND

Melanoma has the highest mortality rate of all skin tumors, and metastases are the major cause of death from it. The molecular mechanism leading to melanoma metastasis is currently unclear.

METHODS

With the goal of revealing the underlying mechanism, three data sets with accession numbers GSE8401, GSE46517 and GSE7956 were downloaded from the Gene Expression Omnibus (GEO) database. After identifying the differentially expressed gene (DEG) of primary melanoma and metastatic melanoma, three kinds of analyses were performed, namely functional annotation, protein-protein interaction (PPI) network and module construction, and co-expression and drug-gene interaction prediction analysis.

RESULTS

A total of 41 up-regulated genes and 79 down-regulated genes was selected for subsequent analyses. Results of pathway enrichment analysis showed that extracellular matrix organization and proteoglycans in cancer are closely related to melanoma metastasis. In addition, seven pivotal genes were identified from PPI network, including CXCL8, THBS1, COL3A1, TIMP3, KIT, DCN, and IGFBP5, which have all been verified in the TCGA database and clinical specimens, but only CXCL8, THBS1 and KIT had significant differences in expression.

CONCLUSIONS

To conclude, CXCL8, THBS1 and KIT may be the hub genes in the metastasis of melanoma and thus may be regarded as therapeutic targets in the future.

LncRNA GAS5 promotes apoptosis as a competing endogenous RNA for miR-21 via thrombospondin 1 in ischemic AKI

Mounting evidence has indicated that long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) played important roles in renal ischemia/reperfusion (I/R) injury. However, the involvement of lncRNA growth arrest specific 5 (GAS5) in acute kidney injury (AKI) remained largely unexplored. This study aimed to determine possible mechanisms of GAS5 in the renal I/R process. We found that GAS5, noticeably upregulated by renal I/R injury, was further suppressed by delayed IPC while knockdown of miR-21 in vivo before IPC could significantly increased the GAS5 levels. Concurrently, TSP-1 was negatively regulated by miR-21 in vivo and vitro. Additionally, Reciprocal repression of GAS5 and miR-21 was identified. Knockdown of miR-21 in H6R0.5 treated HK-2 cells promoted apoptosis. Co-transfection of miR-21 mimic and pcDNA-GAS5 or pcDNA-Vector were performed, results of which showed that inhibition of miR-21 on TSP-1 could be rescued by overexpression of GAS5. This study suggested that GAS5 facilitated apoptosis by competitively sponging miR-21, which negatively regulated TSP-1 in renal I/R injury. This novel regulatory axis could act as a therapeutic target for AKI in the future.

Mouse skin-derived precursors alleviates ultraviolet B irradiation damage via early activation of TGF-β/Smad pathway by thrombospondin1

Our previous research implied mouse skin-derived precursors (mSKPs) possessed the capacity of anti-ultraviolet B (UVB) irradiation damage, and the mechanisms might be associated with transforming growth factor-β (TGF-β) signaling pathway activation. In this study, we investigated and compared the response to UVB irradiation between mSKPs and dermal mesenchymal stem cells (dMSCs), and explored the underlying mechanisms. Irradiation damage such as decreased cell viability, cell senescence, and cell death was observed in both mSKPs and dMSCs at 24 h after UVB exposure. In mSKPs, change in cell morphology, viability, cell senescence and death at the following time points implied the recovery of UVB irradiation damage. Additionally, thrombospondin1 (TSP1) and TGF-β1 increased significantly in mSKPs' supernatant after UVB irradiation. The gene expression of TSP1, TGF-β1, metalloproteinase 1 (MMP1), and Collagen I elevated shortly after the UVB exposure. The protein expression of TSP1, TGF-β1, MMP1, Collagen I, smad2/3, and p-smad2/3 at multiple time points after the UVB exposure was consistent with the gene expression results. In dMSCs, no obvious recovery was noticed. Together, these results revealed that in mSKPs, one of the mechanisms to attenuate the UVB irradiation damage might be the early activation of TGF-β/Smad pathway by TSP1. Given that mSKPs could differentiate into fibroblast-like SKP-derived fibroblasts (SFBs) in vivo or with the presence of serum, mSKPs might serve as a therapeutic potential for fibroblasts supplement and UVB irradiation damage treatment.Abbreviations: SKPs: skin-derived precursors; mSKPs: mouse SKPs; UVB: ultraviolet B; TGF-β/Smad: transforming growth factor-β/Smad; TSP1: thrombospondin 1; MMP 13: metalloproteinases 13; TβRII: TGF-β receptor II; SFBs: SKP-derived fibroblasts; KEGG: Kyoto encyclopedia of genes and genomes; DEGs: differentially expressed genes; dMSCs: dermal mesenchymal stem cells; LM: light microscope; CCK-8: cell counting kit 8; ELISA: Enzyme-linked immuno sorbent assay; qRT-PCR: quantitative real-time polymerase chain reaction; TSPs: thrombospondins; ECM: extracellular matrix; R-smads: receptor-regulated smads.

Lipid Accumulation and Chronic Kidney Disease

Obesity and hyperlipidemia are the most prevalent independent risk factors of chronic kidney disease (CKD), suggesting that lipid accumulation in the renal parenchyma is detrimental to renal function. Non-esterified fatty acids (also known as free fatty acids, FFA) are especially harmful to the kidneys. A concerted, increased FFA uptake due to high fat diets, overexpression of fatty acid uptake systems such as the CD36 scavenger receptor and the fatty acid transport proteins, and a reduced β-oxidation rate underlie the intracellular lipid accumulation in non-adipose tissues. FFAs in excess can damage podocytes, proximal tubular epithelial cells and the tubulointerstitial tissue through various mechanisms, in particular by boosting the production of reactive oxygen species (ROS) and lipid peroxidation, promoting mitochondrial damage and tissue inflammation, which result in glomerular and tubular lesions. Not all lipids are bad for the kidneys: polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) seem to help lag the progression of chronic kidney disease (CKD). Lifestyle interventions, especially dietary adjustments, and lipid-lowering drugs can contribute to improve the clinical outcome of patients with CKD.

Urine Angiotensin II Signature Proteins as Markers of Fibrosis in Kidney Transplant Recipients

BACKGROUND

Interstitial fibrosis/tubular atrophy (IFTA) is an important cause of kidney allograft loss; however, noninvasive markers to identify IFTA or guide antifibrotic therapy are lacking. Using angiotensin II (AngII) as the prototypical inducer of IFTA, we previously identified 83 AngII-regulated proteins in vitro. We developed mass spectrometry-based assays for quantification of 6 AngII signature proteins (bone marrow stromal cell antigen 1, glutamine synthetase [GLNA], laminin subunit beta-2, lysophospholipase I, ras homolog family member B, and thrombospondin-I [TSP1]) and hypothesized that their urine excretion will correlate with IFTA in kidney transplant patients.

METHODS

Urine excretion of 6 AngII-regulated proteins was quantified using selected reaction monitoring and normalized by urine creatinine. Immunohistochemistry was used to assess protein expression of TSP1 and GLNA in kidney biopsies.

RESULTS

The urine excretion rates of AngII-regulated proteins were found to be increased in 15 kidney transplant recipients with IFTA compared with 20 matched controls with no IFTA (mean log2[fmol/µmol of creatinine], bone marrow stromal cell antigen 1: 3.8 versus 3.0, P = 0.03; GLNA: 1.2 versus -0.4, P = 0.03; laminin subunit beta-2: 6.1 versus 5.4, P = 0.06; lysophospholipase I: 2.1 versus 0.6, P = 0.002; ras homolog family member B: 1.2 versus -0.1, P = 0.006; TSP1_GGV: 2.5 versus 1.9; P = 0.15; and TSP1_TIV: 2.0 versus 0.6, P = 0.0006). Receiver operating characteristic curve analysis demonstrated an area under the curve = 0.86 for the ability of urine AngII signature proteins to discriminate IFTA from controls. Urine excretion of AngII signature proteins correlated strongly with chronic IFTA and total inflammation. In a separate cohort of 19 kidney transplant recipients, the urine excretion of these 6 proteins was significantly lower following therapy with AngII inhibitors (P < 0.05).

CONCLUSIONS

AngII-regulated proteins may represent markers of IFTA and guide antifibrotic therapies.

Myeloid-specific deletion of thrombospondin 1 protects against inflammation and insulin resistance in long-term diet-induced obese male mice

Thrombospondin 1 (TSP1) is a multifunctional matricellular protein. Recent studies demonstrate that TSP1 is highly expressed in adipose tissue (AT) and positively associated with AT inflammation and insulin resistance (IR). In this study, the contribution of different cellular sources of TSP1 to obesity-induced metabolic complications is determined by using mice with either adipocyte or myeloid/macrophage-specific deletion of TSP1 in a diet-induced obese model. The results demonstrated that neither adipocyte nor myeloid/macrophage-specific deletion of TSP1 affected the development of long-term high-fat diet-induced obesity. Adipocyte-specific deletion of TSP1 did not protect mice from obesity-induced inflammation and IR. On the contrary, obese mice with myeloid/macrophage loss of TSP1 had reduced macrophage accumulation in AT, which was accompanied with reduced inflammation and improved glucose tolerance and insulin sensitivity compared with obese control mice. Reduced macrophage-derived-TGF-β1 signaling and adipose tissue fibrosis were also observed in long-term high-fat-fed mice with myeloid/macrophage-specific TSP1 deletion. Moreover, in vitro experiments demonstrated an autocrine effect of TSP1-mediated TGF-β activation in macrophages in obesity. Collectively this study highlights the critical contribution of myeloid/macrophage-derived TSP1 to obesity-associated chronic inflammation and IR, which may serve as a new therapeutic target for metabolic disease.

Apigenin Inhibits UVB-Induced Skin Carcinogenesis: The Role of Thrombospondin-1 as an Anti-Inflammatory Factor

We have previously demonstrated that apigenin promotes the expression of antiangiogenic protein thrombospondin-1 (TSP1) via a mechanism driven by mRNA-binding protein HuR. Here, we generated a novel mouse model with whole-body THBS-1 gene knockout on SKH-1 genetic background, which allows studies of UVB-induced acute skin damage and carcinogenesis and tests TSP1 involvement in apigenin's anticancer effects. Apigenin significantly inhibited UVB-induced carcinogenesis in the wild-type (WT) animals but not in TSP1 KO (TKO) mice, suggesting that TSP1 is a critical component of apigenin's chemopreventive function in UVB-induced skin cancer. Importantly, TKO mice presented with the elevated cutaneous inflammation at baseline, which was manifested by increased inflammatory infiltrates (neutrophils and macrophages) and elevated levels of the two key inflammatory cytokines, IL-6 and IL-12. In agreement, maintaining normal TSP1 expression in the UVB-irradiated skin of WT mice using topical apigenin application caused a marked decrease of circulating inflammatory cytokines. Finally, TKO mice showed an altered population dynamics of the bone marrow myeloid progenitor cells (CD11b+), with dramatic expansion of the population of neutrophil progenitors (Ly6ClowLy6Ghigh) compared to the WT control. Our results indicate that the cutaneous tumor suppressor TSP1 is a critical mediator of the in vivo anticancer effect of apigenin in skin, specifically of its anti-inflammatory action.

Thrombospondin-1 regulation of latent TGF-β activation: A therapeutic target for fibrotic disease

Transforming growth factor-β (TGF-β) is a central player in fibrotic disease. Clinical trials with global inhibitors of TGF-β have been disappointing, suggesting that a more targeted approach is warranted. Conversion of the latent precursor to the biologically active form of TGF-β represents a novel approach to selectively modulating TGF-β in disease, as mechanisms employed to activate latent TGF-β are typically cell, tissue, and/or disease specific. In this review, we will discuss the role of the matricellular protein, thrombospondin 1 (TSP-1), in regulation of latent TGF-β activation and the use of an antagonist of TSP-1 mediated TGF-β activation in a number of diverse fibrotic diseases. In particular, we will discuss the TSP-1/TGF-β pathway in fibrotic complications of diabetes, liver fibrosis, and in multiple myeloma. We will also discuss emerging evidence for a role for TSP-1 in arterial remodeling, biomechanical modulation of TGF-β activity, and in immune dysfunction. As TSP-1 expression is upregulated by factors induced in fibrotic disease, targeting the TSP-1/TGF-β pathway potentially represents a more selective approach to controlling TGF-β activity in disease.

Thrombospondin immune regulation and the kidney

Most therapeutic attempts to prevent the progression of kidney diseases have been based on interventions to inhibit the production of transforming growth factor-β (TGF-β). Thrombospondins (TSPs) play an important role in activating TGF-β. In the healthy kidney, two TSPs are expressed, TSP1 and TSP2, which exert contrasting effects. While TSP1 is a major activator of TGF-β in renal cells and exerts pro-inflammatory effects both in vitro and in vivo, TSP2 lacks the ability for TGF-β activation but regulates matrix remodeling and inflammation in experimental kidney disease. The effects of TSPs in the kidney have been mostly investigated by using the murine model of unilateral ureteral obstruction. In this model, TSP1 expression is increased along with the development of interstitial fibrosis and TGF-β. Relief of the obstruction gradually improves renal function and decreases the expression in TSP1 and TGF-β1. Several inhibitors of TSP1 prevented progressive interstitial fibrosis in murine models of ureteral obstruction, suggesting that control of latent TGF-β activation by inhibiting TSP1 might represent a novel potential target for preventing renal interstitial fibrosis. However, further studies are needed to assess whether TSP1-mediated TGF-β activation can be safely used in humans. In fact, TSPs normally act to suppress tumors in vivo. Moreover, TGF-β can exert a pivotal function in the immune system, as it may induce the production of regulatory T cells and suppress B cell responses. Knowledge of the molecular mechanisms involved in TGF-β regulation may help in finding effective treatments of tissue fibrosis, cancer and autoimmune disease.

Amphotericin B-copper (II) complex alters transcriptional activity of genes encoding transforming growth factor-beta family members and related proteins in renal cells

BACKGROUND

Several chemical modifications have been developed to overcome the toxicity of amphotericin B (AmB). Oxidized forms of AmB (AmB-ox), which may occur in patient's circulation during therapy, are as toxic as AmB. Complexes with copper (II) ions (AmB-Cu²⁺) have been reported to be less toxic to human cells. Previous studies showed that AmB changed the expression of transforming growth factor-beta (TGF-β). Therefore, the objective of this study was to investigate the influence of AmB and its modified forms on the expression of genes encoding for TGF-β family members and related proteins in renal cells.

METHODS

Human renal proximal tubule cells (RPTEC) were treated with AmB-Cu²⁺, AmB, or the oxidized form AmB-ox. The expression of TGF-β family members and related genes was determined using oligonucleotide microarrays. TGF-β1 protein level was determined using ELISA method. The mRNA level of TGF-β isoforms, TGF-β receptors and differentiating genes was evaluated by real-time RT-qPCR.

RESULTS

AmB-Cu²⁺ increased the mRNA levels of TGF-β1 and TGF-β2 isoforms and two genes encoding receptors: TGFBR1 and TGFBR2. TGF-β1 protein level in culture medium was not increased after stimulation with AmB-Cu²⁺. Microarray analysis revealed changes in both pro-fibrotic and anti-fibrotic genes.

CONCLUSIONS

These results suggest that AmB-Cu²⁺ may induce repair mechanisms in renal proximal tubule cells via changes in the expression of genes involved in intracellular signaling.

The pathogenesis of diclofenac induced immunoallergic hepatitis in a canine model of liver injury

Hypersensitivity to non-steroidal anti-inflammatory drugs is a common adverse drug reaction and may result in serious inflammatory reactions of the liver. To investigate mechanism of immunoallergic hepatitis beagle dogs were given 1 or 3 mg/kg/day (HD) oral diclofenac for 28 days. HD diclofenac treatment caused liver function test abnormalities, reduced haematocrit and haemoglobin but induced reticulocyte, WBC, platelet, neutrophil and eosinophil counts. Histopathology evidenced hepatic steatosis and glycogen depletion, apoptosis, acute lobular hepatitis, granulomas and mastocytosis. Whole genome scans revealed 663 significantly regulated genes of which 82, 47 and 25 code for stress, immune response and inflammation. Immunopathology confirmed strong induction of IgM, the complement factors C3&B, SAA, SERPING1 and others of the classical and alternate pathway. Alike, marked expression of CD205 and CD74 in Kupffer cells and lymphocytes facilitate antigen presentation and B-cell differentiation. The highly induced HIF1A and KLF6 protein expression in mast cells and macrophages sustain inflammation. Furthermore, immunogenomics discovered 24, 17, 6 and 11 significantly regulated marker genes to hallmark M1/M2 polarized macrophages, lymphocytic and granulocytic infiltrates; note, the latter was confirmed by CAE staining. Other highly regulated genes included alpha-2-macroglobulin, CRP, hepcidin, IL1R1, S100A8 and CCL20. Diclofenac treatment caused unprecedented induction of myeloperoxidase in macrophages and oxidative stress as shown by SOD1/SOD2 immunohistochemistry. Lastly, bioinformatics defined molecular circuits of inflammation and consisted of 161 regulated genes.

Altogether, the mechanism of diclofenac induced liver hypersensitivity reactions involved oxidative stress, macrophage polarization, mastocytosis, complement activation and an erroneous programming of the innate and adaptive immune system.

Renal Protection Mediated by Hypoxia Inducible Factor-1α Depends on Proangiogenesis Function of miR-21 by Targeting Thrombospondin 1

Background

Angiogenesis contributes to the repair process after renal ischemia/reperfusion (I/R) injury. In the present study, we tested the role of miR-21 in the angiogenesis induced by hypoxia inducible factor (HIF)-1α through inhibiting a predicted target gene thrombospondin 1 (TSP-1).

Methods

To stabilize HIF-1α, hypoxia (1% O₂ for 24 hours) was performed in human umbilical vein endothelial cells and cobalt chloride (CoCl₂) was pretreated intraperitoneally 24 hours before renal I/R in mice. Locked nucleic acid modified anti-miR-21 and scrambled control was transfected with hypoxic cells or delivered into the mice via tail vein 1 hour before CoCl₂ injection. The kidneys and blood were collected at 24 hours after reperfusion.

Results

HIF-1α induced by hypoxia and CoCl₂ upregulated vascular endothelial growth factor and miR-21, and increased angiogenesis. It was found that expression of TSP-1 was inversely related with miR-21 in vitro and in vivo. Targeting of TSP-1 by miR-21 was further confirmed in vitro. Furthermore, HIF-1α improved renal function, accompanied with increased angiogenesis after I/R injury in mice. The protective effect of HIF-1α was attenuated by inhibition of miR-21.

Conclusions

HIF-1α induced angiogenesis by upregulating not only vascular endothelial growth factor but also miR-21 via inhibiting a novel target gene TSP-1. Both of them may contribute to the protective effect of HIF-1α on renal I/R injury.

Hypoxia induces HIF-1α which upregulates not only VEGF but also miR-21, and this last one inhibits a novel target gene, thrombospondin 1. Angiogenesis induced by hypoxia depends at least partially on production of VEGF and inhibition of thrombospondin 1 through miR-21.

β1-Integrin Deletion From the Lens Activates Cellular Stress Responses Leading to Apoptosis and Fibrosis

Purpose

Previous research showed that the absence of β1-integrin from the mouse lens after embryonic day (E) 13.5 (β1MLR10) leads to the perinatal apoptosis of lens epithelial cells (LECs) resulting in severe microphthalmia. This study focuses on elucidating the molecular connections between β1-integrin deletion and this phenotype.

Methods

RNA sequencing was performed to identify differentially regulated genes (DRGs) in β1MLR10 lenses at E15.5. By using bioinformatics analysis and literature searching, Egr1 (early growth response 1) was selected for further study. The activation status of certain signaling pathways (focal adhesion kinase [FAK]/Erk, TGF-β, and Akt signaling) was studied via Western blot and immunohistochemistry. Mice lacking both β1-integrin and Egr1 genes from the lenses were created (β1MLR10/Egr1-/-) to study their relationship.

Results

RNA sequencing identified 120 DRGs that include candidates involved in the cellular stress response, fibrosis, and/or apoptosis. Egr1 was investigated in detail, as it mediates cellular stress responses in various cell types, and is recognized as an upstream regulator of numerous other β1MLR10 lens DRGs. In β1MLR10 mice, Egr1 levels are elevated shortly after β1-integrin loss from the lens. Further, pErk1/2 and pAkt are elevated in β1MLR10 LECs, thus providing the potential signaling mechanism that causes Egr1 upregulation in the mutant. Indeed, deletion of Egr1 from β1MLR10 lenses partially rescues the microphthalmia phenotype.

Conclusions

β1-integrin regulates the appropriate levels of Erk1/2 and Akt phosphorylation in LECs, whereas its deficiency results in the overexpression of Egr1, culminating in reduced cell survival. These findings provide insight into the molecular mechanism underlying the microphthalmia observed in β1MLR10 mice.

Thrombospondin-1 promotes cell migration, invasion and lung metastasis of osteosarcoma through FAK dependent pathway

Microenvironment at the metastatic locus usually differs greatly from that present in the site of primary tumor formation and it has a significant impact on the fate of the extravasated cancer cells. We compared gene expression signatures of primary tumors and lung metastatic tumors, and identified Thrombospondin-1 (TSP1) as highly up-regulated in the lung metastatic tumors. Immunohistochemical staining further indicated that TSP1 protein expression was higher in lung metastatic tumors compared to primary tumors in both osteosarcoma xenograft model and human clinical samples. TSP1 mRNA level is significantly associated with the Enneking stage of osteosarcoma and lung metastasis. TGF-β pathways could stimulate the TSP1 expression in osteosarcoma cells. Knockdown of TSP1 expression in osteosarcoma cells dramatically suppressed cell wound healing, migration and invasion. Treatment with recombinant TSP1 protein in osteosarcoma cells significantly promoted cell wound healing, migration and invasion. Meanwhile, suppression of TSP1 in osteosarcoma cells resulted in decreased pulmonary metastasis in vivo. Mechanistically, TSP1 increased expression of metastasis related genes, including MMP2, MMP9 and Fibronectin 1. TSP1 promoted osteosarcoma cell motility through the activation of FAK pathway. Taken together, our study provides evidence of the contributions of TSP1 to the lung metastasis of osteosarcoma and suggests that this protein may represent a potential therapeutic target for osteosarcoma lung metastasis.

Role of thrombospondin 1 in liver diseases

Thrombospondin 1 (TSP1) is a matricellular glycoprotein that can be secreted by many cell types. Through binding to extracellular proteins and/or cell surface receptors, TSP1 modulates a variety of cellular functions. Since its discovery in 1971, TSP1 has been found to play important roles in multiple biological processes including angiogenesis, apoptosis, latent transforming growth factor-β activation, and immune regulation. Thrombospondin 1 is also involved in regulating many organ functions. However, the role of TSP1 in liver diseases has not been extensively addressed. In this review, we summarize the findings about the possible role that TSP1 plays in chronic liver diseases focusing on non-alcoholic fatty liver diseases, liver fibrosis, and hepatocellular carcinoma.

Extracorporeal shock wave therapy does not improve hypertensive nephropathy

Low-energy extracorporeal shock wave therapy (SWT) has been shown to improve myocardial dysfunction, hind limb ischemia, erectile function, and to facilitate cell therapy and healing process. These therapeutic effects were mainly due to promoting angiogenesis. Since chronic kidney diseases are characterized by renal fibrosis and capillaries rarefaction, they may benefit from a proangiogenic treatment. The objective of our study was to determine whether SWT could ameliorate renal repair and favor angiogenesis in L-NAME-induced hypertensive nephropathy in rats. SWT was started when proteinuria exceeded 1 g/mmol of creatinine and 1 week after L-NAME removal. SWT consisted of implying 0.09 mJ/mm(2) (400 shots), 3 times per week. After 4 weeks of SWT, blood pressure, renal function and urinary protein excretion did not differ between treated (LN + SWT) and untreated rats (LN). Histological lesions including glomerulosclerosis and arteriolosclerosis scores, tubular dilatation and interstitial fibrosis were similar in both groups. In addition, peritubular capillaries and eNOS, VEGF, VEGF-R, SDF-1 gene expressions did not increase in SWT-treated compared to untreated animals. No procedural complications or adverse effects were observed in control (C + SWT) and hypertensive rats (LN + SWT). These results suggest that extracorporeal kidney shock wave therapy does not induce angiogenesis and does not improve renal function and structure, at least in the model of hypertensive nephropathy although the treatment is well tolerated.

Thrombospondin 1 Deficiency Ameliorates the Development of Adriamycin-Induced Proteinuric Kidney Disease

Accumulating evidence suggests that thrombospondin 1 (TSP1) is an important player in diabetic nephropathy. However, the role of TSP1 in podocyte injury and the development of non-diabetic proteinuric kidney disease is largely unknown. In the current study, by using a well-established podocyte injury model (adriamycin-induced nephropathy mouse model), we examined the contribution of TSP1 to the development of proteinuric kidney disease. We found that TSP1 was up-regulated in the glomeruli, notably in podocytes, in adriamycin injected mice before the onset of proteinuria. ADR treatment also stimulated TSP1 expression in cultured human podocytes in vitro. Moreover, increased TSP1 mediated ADR-induced podocyte apoptosis and actin cytoskeleton disorganization. This TSP1's effect was through a CD36-dependent mechanism and involved in the stimulation of p38MAPK pathway. Importantly, in vivo data demonstrated that TSP1 deficiency protected mice from ADR induced podocyte loss and foot process effacement. ADR induced proteinuria, glomerulosclerosis, renal macrophage infiltration and inflammation was also attenuated in TSP1 deficient mice. Taken together, these studies provide new evidence that TSP1 contributes to the development of non-diabetic proteinuric kidney disease by stimulating podocyte injury and the progression of renal inflammation.

Interaction of thrombospondin1 and CD36 contributes to obesity-associated podocytopathy

Obesity is associated with podocyte injury and the development of proteinuria. Elevated plasma free fatty acid is one of the characteristics of obesity and has been linked to podocyte dysfunction. However, the mechanisms remain unclear. In the current study, we examined the effect of saturated free fatty acid (FFA) on human podocyte apoptosis and function in vitro. The mechanism and its in vivo relevance were also determined. We found that FFA treatment induced human podocyte apoptosis and dysfunction, which was associated with increased expression of a matricellular protein-thrombospondin1 (TSP1). FFA stimulated TSP1 expression in podocytes at the transcriptional levels through activation of MAPK pathway. Addition of purified TSP1 to cell culture media induced podocyte apoptosis and dysfunction. Tis effect is though a TGF-β independent mechanism. Moreover, peptide treatment to block TSP1 binding to its receptor-CD36 attenuated FFA induced podocyte apoptosis, suggesting that TSP1/CD36 interaction mediates FFA-induced podocyte apoptosis. Importantly, using a diet-induced obese mouse model, in vivo data demonstrated that obesity-associated podocyte apoptosis and dysfunction were attenuated in TSP1 deficient mice as well as in CD36 deficient mice. Taken together, these studies provide novel evidence that the interaction of TSP1 with its receptor CD36 contributes to obesity--associated podocytopathy.

Thrombospondin 1 promotes an aggressive phenotype through epithelial-to-mesenchymal transition in human melanoma

Epithelial-to-mesenchymal transition (EMT), in which epithelial cells loose their polarity and become motile mesenchymal cells, is a determinant of melanoma metastasis. We compared gene expression signatures of mesenchymal-like melanoma cells with those of epithelial-like melanoma cells, and identified Thrombospondin 1 (THBS1) as highly up-regulated in the mesenchymal phenotype. This study investigated whether THBS1, a major physiological activator of transforming growth factor (TGF)-beta, is involved in melanoma EMT-like process. We sought to examine expression patterns in distinct melanoma phenotypes including invasive, de-differentiated, label-retaining and drug resistant populations that are putatively associated with an EMT-like process.

Here we show that THBS1 expression and secretion was elevated in melanoma cells exhibiting invasive, drug resistant, label retaining and mesenchymal phenotypes and correlated with reduced expression of genes involved in pigmentation. Elevated THBS1 levels were detected in Vemurafenib resistant melanoma cells and inhibition of THBS1 led to significantly reduced chemoresistance in melanoma cells. Notably, siRNA-mediated silencing of THBS1 and neutralizing antibody to THBS1 reduced invasion in mesenchymal-like melanoma cells, while ectopic THBS1 expression in epithelial-like melanoma cells enhanced invasion. Furthermore, the loss of THBS1 inhibited in vivo motility of melanoma cells within the embryonic chicken neural tube. In addition, we found aberrant THBS1 protein expression in metastatic melanoma tumor biopsies. These results implicate a role for THBS1 in EMT, and hence THBS1 may serve as a novel target for strategies aimed at the treatment of melanoma invasion and drug resistance.

The Thrombospondin1-TGF-β Pathway and Glaucoma

Glaucoma is characterized by abnormal remodeling of the extracellular matrix (ECM) in the trabecular meshwork and in the connective tissue beams of the lamina cribrosa (LC) at the optic nerve head (ONH), which is associated with axonal damage. Mechanical strain can stimulate ECM remodeling and increased expression of matricellular proteins. Thrombospondins 1 and 2 are induced by cyclic mechanical strain in the eye in both the trabecular meshwork and in the LC region of the ONH. TGF-betas 1 and 2 are increased in glaucoma and play a role in the pathologic remodeling of the ECM in the eye in glaucoma. In this study, we address the role of thrombospondin1 as a regulator of latent TGF-beta activation and discuss the potential therapeutic use of antagonists of the thrombospondin1-TGF-beta pathway for treatment of glaucoma.

Discoidin domain receptor-1 and periostin: new players in chronic kidney disease

The incidence and prevalence of chronic kidney disease represents an important problem for public health. In renal diseases, the main histologic alterations derive from the development of renal fibrosis which results from the loss of the balance between pro- and anti-fibrotic factors. Tyrosine kinase receptors (RTKs) and matricellular proteins (MPs) are nowadays studied as potential modulators of renal injury. RTKs regulate cell cycle, migration, metabolism and cellular differentiation. Discoidin domain receptor-1 (DDR-1) is an RTK that has been extensively studied in cancer, and lung and renal diseases. It modulates inflammatory recruitment, extracellular matrix deposition and fibrosis; in renal diseases, it appears to act independently of the underlying disease. MPs regulate cell-matrix interactions and matrix accumulation, cellular adhesion and migration, and expression of inflammatory cells. Periostin is an MP, mainly studied in bone, heart, lung and cancer. Several studies demonstrated that it mediates cell-matrix interactions, migration of inflammatory cells and development of fibrosis. Recently, it has been reported in several nephropathies. In this review, we discuss the potential pathological roles of DDR-1 and periostin focussing on the kidney in both experimental models and human diseases.

Comparison of the transcriptomes of mouse skin derived precursors (SKPs) and SKP-derived fibroblasts (SFBs) by RNA-Seq

Skin-derived precursors (SKPs) from dermis possess the capacities of self-renewal and multipotency. In vitro and in vivo studies demonstrated that they can differentiate into fibroblasts. However, little is known about the molecular mechanism of the differentiation of SKPs into fibroblasts. Here we compare the transcriptomes of mouse SKPs and SKP-derived fibroblasts (SFBs) by RNA-Seq analysis, trying to find differences in gene expression between the two kinds of cells and then elucidate the candidate genes that may play important roles in the differentiation of SKPs into fibroblasts. A total of 1971 differentially expressed genes (DEGs) were identified by RNA-Seq, which provided abundant data for further analysis. Gene Ontology enrichment analysis revealed that genes related to cell differentiation, cell proliferation, protein binding, transporter activity and membrane were significantly enriched. The most significantly up-regulated genes Wnt4, Wisp2 and Tsp-1 and down-regulated genes Slitrk1, Klk6, Agtr2, Ivl, Msx1, IL15, Atp6v0d2, Kcne1l and Thbs4 may play important roles in the differentiation of SKPs into fibroblasts. KEGG analysis showed that DEGs were significantly enriched in the TGF-β signaling pathway, Wnt signaling pathway and Notch signaling pathway, which have been previously proven to regulate the differentiation and self-renewal of various stem cells. These identified DEGs and pathways could facilitate further investigations of the detailed molecular mechanisms, making it possible to take advantage of the potential therapeutic applications of SKPs in skin regeneration in the future.

Thrombospondin-1 deficiency causes a shift from fibroproliferative to inflammatory kidney disease and delays onset of renal failure

Thrombospondin-1 (TSP1) is a multifunctional matricellular protein known to promote progression of chronic kidney disease. To gain insight into the underlying mechanisms through which TSP1 accelerates chronic kidney disease, we compared disease progression in Col4a3 knockout (KO) mice, which develop spontaneous kidney failure, with that of Col4a3;Tsp1 double-knockout (DKO) mice. Decline of excretory renal function was significantly delayed in the absence of TSP1. Although Col4a3;Tsp1 DKO mice did progress toward end-stage renal failure, their kidneys exhibited distinct histopathological lesions, compared with creatinine level-matched Col4a3 KO mice. Although kidneys of both Col4a3 KO and Col4a3;Tsp1 DKO mice exhibited a widened tubulointerstitium, predominant lesions in Col4a3 KO kidneys were collagen deposition and fibroblast accumulation, whereas in Col4a3;Tsp1 DKO kidney inflammation was predominant, with less collagen deposition. Altered disease progression correlated with impaired activation of transforming growth factor-β1 (TGF-β1) in vivo and in vitro in the absence of TSP1. In summary, our findings suggest that TSP1 contributes to progression of chronic kidney disease by catalyzing activation of latent TGF-β1, resulting in promotion of a fibroproliferative response over an inflammatory response. Furthermore, the findings suggest that fibroproliferative and inflammatory lesions are independent entities, both of which contribute to decline of renal function.

The role of epigenetics in the fibrotic processes associated with glaucoma

Glaucoma is an optic neuropathy that affects 60 million people worldwide. The main risk factor for glaucoma is increased intraocular pressure (IOP), this is currently the only target for treatment of glaucoma. However, some patients show disease progression despite well-controlled IOP. Another possible therapeutic target is the extracellular matrix (ECM) changes in glaucoma. There is an accumulation of ECM in the lamina cribrosa (LC) and trabecular meshwork (TM) and upregulation of profibrotic factors such as transforming growth factor β (TGFβ), collagen1α1 (COL1A1), and α-smooth muscle actin (αSMA). One method of regulating fibrosis is through epigenetics; the study of heritable changes in gene function caused by mechanisms other than changes in the underlying DNA sequence. Epigenetic mechanisms have been shown to drive renal and pulmonary fibrosis by upregulating profibrotic factors. Hypoxia alters epigenetic mechanisms through regulating the cell's response and there is a hypoxic environment in the LC and TM in glaucoma. This review looks at the role that hypoxia plays in inducing aberrant epigenetic mechanisms and the role these mechanisms play in inducing fibrosis. Evidence suggests that a hypoxic environment in glaucoma may induce aberrant epigenetic mechanisms that contribute to disease fibrosis. These may prove to be relevant therapeutic targets in glaucoma.