Collagens, collagen-binding heat shock protein 47 and transforming growth factor-beta 1 are induced in cicatricial pemphigoid: possible role(s) in dermal fibrosis

The Synthesis and Biological Applications of the 1,2,3-Dithiazole Scaffold

The 1,2,3-dithiazole is an underappreciated scaffold in medicinal chemistry despite possessing a wide variety of nascent pharmacological activities. The scaffold has a potential wealth of opportunities within these activities and further afield. The 1,2,3-dithiazole scaffold has already been reported as an antifungal, herbicide, antibacterial, anticancer agent, antiviral, antifibrotic, and is a melanin and Arabidopsis gibberellin 2-oxidase inhibitor. These structure activity relationships are discussed in detail, along with insights and future directions. The review also highlights selected synthetic strategies developed towards the 1,2,3-dithiazole scaffold, how these are integrated to accessibility of chemical space, and to the prism of current and future biological activities.

Subunit-Specific Reactivity of Autoantibodies Against Laminin-332 Reveals Direct Inflammatory Mechanisms on Keratinocytes

Laminin-332 pemphigoid is a rare and severe autoimmune blistering disease, caused by IgG autoantibodies targeting laminin-332 in the dermal-epidermal basement zone. Laminin-332 pemphigoid is characterized by variable inflammatory infiltrate and the predominance of non-complement-fixing antibodies. Given these findings, we hypothesized that IgG autoantibodies to laminin-332 directly resulted in keratinocyte expression of inflammatory factors. We performed RNA-seq on primary human keratinocytes treated with IgG from patients with laminin-332 pemphigoid. Genes for numerous cytokines and chemokines were upregulated, including CSF2, CSF3, CXCL1, CXCL5, CXCL3, CXCL8, CXCL10, CXCL1, IL6, IL7, IL15, IL23, IL32, IL37, TGFB2 as well as metalloproteases. Considering the pro-inflammatory and proteolytic effect of autoantibodies from patients with laminin-332 pemphigoid identified in our initial experiment, we next questioned whether the reactivity against specific laminin subunits dictates the inflammatory and proteolytic keratinocyte response. Then, we treated keratinocytes with IgG from a separate cohort of patients with reactivity against individual subunits of laminin-332. We identified upregulation of IL-1α, IL-6, IL-8, CXCL1, MMP9, TSLP, and GM-CSF at the protein level, most notably in keratinocytes treated with IgG from laminin β3-reactive patients. We for the first time demonstrated a pro-inflammatory response, similar to that described in keratinocytes treated with IgG autoantibodies from patients with bullous pemphigoid, providing novel insight into the pathogenesis of laminin-332 pemphigoid and laminin-332 biology.

Expression of heat shock protein 47, transforming growth factor-beta 1, and connective tissue growth factor in liver tissue of patients with Schistosoma japonicum-induced hepatic fibrosis

SUMMARY To detect the expression of pro-fibrotic molecules, such as heat shock protein 47 (Hsp47), transforming growth factor-beta 1 (TGF-β1) and connective tissue growth factor (CTGF) in liver specimens, and analyse their correlations with the progression of schistosomal hepatic fibrosis, liver biopsy was performed in 42 chronic schistosomiasis (CS) patients, 16 chronic hepatitis B (CHB) patients and five healthy individuals (HI). Immunohistochemistry (IHC) analyses displayed that the expression of Hsp47, TGF-β1 and CTGF was increased in CS and CHB patients compared with HI. Using real-time PCR, the mRNA levels of Hsp47, TGF-β1 and CTGF were higher in CS patients compared with HI. In CS patients, the mRNA levels of these genes were correlated with the stage of fibrosis, and TGF-β1 mRNA expression was associated with the grade of inflammation. Additional analyses indicated that the mRNA levels of Hsp47 and CTGF were highly correlated with liver stiffness value and spleen thickness diameter, both of which represented the severity of fibrosis. In conclusion, the three molecules are involved in the pathogenesis of hepatic fibrosis infected by Schistosoma japonicum. TGF-β1 participates not only in the inflammatory process, but also in the fibrotic process in which Hsp47 and CTGF probably play a key role.

Turkistani K, Razzaque MS. Heat shock protein 47: a novel biomarker of phenotypically altered collagen-producing cells

Heat shock protein 47 (HSP47) is a collagen-specific molecular chaperone that helps the molecular maturation of various types of collagens. A close association between increased expression of HSP47 and the excessive accumulation of collagens is found in various human and experimental fibrotic diseases. Increased levels of HSP47 in fibrotic diseases are thought to assist in the increased assembly of procollagen, and thereby contribute to the excessive deposition of collagens in fibrotic areas. Currently, there is not a good universal histological marker to identify collagen-producing cells. Identifying phenotypically altered collagen-producing cells is essential for the development of cell-based therapies to reduce the progression of fibrotic diseases. Since HSP47 has a single substrate, which is collagen, the HSP47 cellular expression provides a novel universal biomarker to identify phenotypically altered collagen-producing cells during wound healing and fibrosis. In this brief article, we explained why HSP47 could be used as a universal marker for identifying phenotypically altered collagen-producing cells.

Increased expression of collagens, transforming growth factor-beta1, and -beta3 in gluteal muscle contracture

Backgroud

Gluteal muscle contracture (GMC) is a multi-factor human chronic fibrotic disease of the gluteal muscle. Fibrotic tissue is characterized by excessive accumulation of collagen in the muscle's extracellular matrix. Transforming growth factor (TGF)-β1 and -β2 are thought to play an important role in fibrogenesis, while TGF-β3 is believed to have an anti-fibrotic function. We hypothesize that the expression of collagen and TGF-βs would be up-regulated in GMC patients.

Methods

The expression of collagen type I, type III and TGF-βs were studied in 23 fibrotic samples and 23 normal/control samples in GMC patients using immunohistochemistry, reverse transcription and polymerase chain reaction (RT-PCR) and western bolt analysis.

Results

Compared to the unaffected adjacent muscle, increased expression of TGF-β1 and -β3 was associated with deposition of collagen type I and type III in the fibrotic muscle of the GMC patients at the mRNA level. Strong up-regulation of these proteins in fibrotic muscle was confirmed by immunohistochemical staining and western blot analysis. TGF-β2 was not up-regulated in relation to GMC.

Conclusion

This study confirmed our hypothesis that collagen types I, III, TGF-β1 and TGF-β3 were up-regulated in biopsy specimens obtained from patients with GMC. Complex interaction of TGF-β1 with profibrotic function and TGF-β3 with antifibrotic function may increase synthesis of collagens and thereby significantly contribute to the process of gluteal muscle scarring in patients with GMC.

Blockade of advanced glycation end product formation attenuates bleomycin-induced pulmonary fibrosis in rats

BACKGROUND

Advanced glycation end products (AGEs) have been proposed to be involved in pulmonary fibrosis, but its role in this process has not been fully understood. To investigate the role of AGE formation in pulmonary fibrosis, we used a bleomycin (BLM)-stimulated rat model treated with aminoguanidine (AG), a crosslink inhibitor of AGE formation.

METHODS

Rats were intratracheally instilled with BLM (5 mg/kg) and orally administered with AG (40, 80, 120 mg/kg) once daily for two weeks. AGEs level in lung tissue was determined by ELISA and pulmonary fibrosis was evaluated by Ashcroft score and hydroxyproline assay. The expression of heat shock protein 47 (HSP47), a collagen specific molecular chaperone, was measured with RT-PCR and Western blot. Moreover, TGFbeta1 and its downstream Smad proteins were analyzed by Western blot.

RESULTS

AGEs level in rat lungs, as well as lung hydroxyproline content and Ashcroft score, was significantly enhanced by BLM stimulation, which was abrogated by AG treatment. BLM significantly increased the expression of HSP47 mRNA and protein in lung tissues, and AG treatment markedly decreased BLM-induced HSP47 expression in a dose-dependent manner (p < 0.05). In addition, AG dose-dependently downregulated BLM-stimulated overexpressions of TGFbeta1, phosphorylated (p)-Smad2 and p-Smad3 protein in lung tissues.

CONCLUSION

These findings suggest AGE formation may participate in the process of BLM-induced pulmonary fibrosis, and blockade of AGE formation by AG treatment attenuates BLM-induced pulmonary fibrosis in rats, which is implicated in inhibition of HSP47 expression and TGFbeta/Smads signaling.

Suppression of renal tubulointerstitial fibrosis by small interfering RNA targeting heat shock protein 47

BACKGROUND/AIM

Unilateral ureteral obstruction (UUO) is a well-established model for tubulointerstitial fibrosis. During the progression of tubulointerstitial fibrosis, upregulation of collagen synthesis and subsequent accumulation of collagen were observed in the tubulointerstitial area. Heat shock protein 47 (HSP47) is a collagen-specific molecular chaperone and plays an essential role in regulating collagen synthesis. We designed small interfering RNA (siRNA) sequences for HSP47 mRNA to examine whether HSP47 is involved in the progression of renal tubulointerstitial fibrosis in a mouse UUO model.

METHODS

The HSP47 siRNA was injected once via the ureter at the time of UUO preparation. We also applied a new gene delivery system for siRNA using cationized gelatin microspheres. The kidneys were harvested 7 and 14 days after UUO. The HSP47 and type I, III, and IV collagen expression levels were analyzed by immunohistochemistry and Western blotting.

RESULTS

Seven days after UUO, the expression levels of HSP47 and type I, III, and IV collagens were markedly upregulated in obstructed kidneys or green fluorescent protein siRNA treated obstructed kidneys. HSP47 siRNA injection significantly reduced the protein expression levels and significantly diminished the accompanying interstitial fibrosis. Moreover, cationized gelatin microspheres as a delivery system enhanced and lengthened the antifibrotic effect of HSP47 siRNA.

CONCLUSIONS

Our results indicate that HSP47 is a candidate target for the prevention of tubulointerstitial fibrosis and that selective blockade of the HSP47 expression by using siRNA could be a potentially useful therapeutic approach for patients with renal disease.

The collagen-specific molecular chaperone HSP47: is there a role in fibrosis?

Heat shock protein 47 (HSP47) is a collagen-specific molecular chaperone that is required for molecular maturation of various types of collagens. Recent studies have shown a close association between increased expression of HSP47 and excessive accumulation of collagens in scar tissues of various human and experimental fibrotic diseases. It is presumed that the increased levels of HSP47 in fibrotic diseases assist in excessive assembly and intracellular processing of procollagen molecules and, thereby, contribute to the formation of fibrotic lesions. Studies have also shown that suppression of HSP47 expression can reduce accumulation of collagens to delay the progression of fibrotic diseases in experimental animal models. Because HSP47 is a specific chaperone for collagen synthesis, it provides a selective target to manipulate collagen production, a phenomenon that might have enormous clinical impact in controlling a wide range of fibrotic diseases. Here, we outline the fibrogenic role of HSP47 and discuss the potential usefulness of HSP47 as an anti-fibrotic therapeutic target.

Generation and Differentiation of Human Embryonic Stem Cell-Derived Keratinocyte Precursors

Human embryonic stem cells (hESC) hold tremendous potential in the future of tissue engineering, offering promise as a source of virtually unlimited quantities of desired cell and tissue types. We have identified soluble chemical and extracellular matrix factors that permit isolation of keratinocyte precursors from hESCs. Culturing embryoid bodies (EB) formed from hESCs in a defined serum-free keratinocyte growth medium on a gelatin matrix generated keratin 14 (K14) expressing cells with an epithelial morphology. These K14 expressing cells could be subcultured in medium supplemented with hydrocortisone and induced to stratify and terminally differentiate by addition of calcium. Optimum times for obtaining K14 expressing cells were found for EB formation and for differentiation and growth of cultures after EB plating. EB formation was not necessary to generate keratinocyte precursors; direct transfer of hESC colonies to keratinocyte growth medium permitted differentiation into the keratinocyte lineage. With further studies to optimize generation and purification of hESC-derived keratinocyte precursors, these cells could provide a source of epidermal cells for skin tissue engineering applications in vitro or in vivo.

Developmental regulation and coordinate reexpression of FKBP65 with extracellular matrix proteins after lung injury suggest a specialized function for this endoplasmic reticulum immunophilin

AFKBP65 (65-kDa FK506-binding protein) is an endoplasmic reticulum (ER)-localized peptidyl-prolyl cis-trans isomerase predicted to play a role in the folding and trafficking of secretory proteins. In previous studies, we have shown that FKBP65 is developmentally regulated and associates with the extracellular matrix protein, tropoelastin, during its maturation and transport through the ER. In this study, we show that FKBP65 is expressed in the lung with the same developmental pattern as tropoelastin and other matrix proteins. To test the hypothesis that FKBP65 is upregulated at times when extracellular matrix proteins are being actively synthesized and assembled, adult mice were treated with bleomycin to cause reinitiation of matrix protein production during the ensuing development of pulmonary fibrosis. After bleomycin instillation, FKBP65 expression was reactivated in the lung with a pattern similar to that observed for tropoelastin and type I collagen. Using human lung fibroblast cultures, we showed that FKBP65 does not undergo the unfolded protein response, a response associated with an upregulation of resident ER proteins that occurs after increased ER stress. When fibroblasts were treated with transforming growth factor (TGF)-beta1, which is upregulated during the development of pulmonary fibrosis and known to induce matrix production, FKBP65 expression and synthesis was also increased. Similar to type I collagen and tropoelastin, this response was completely inhibited in a dose-dependent manner by GGTI-298, a geranylgeranyl transferase I inhibitor. Treatment of fibroblasts with an inhibitor of ribonucleic acid (RNA) polymerase II after TGF-beta1 treatment showed that the effect of TGF-beta1 was not because of increased stabilization of the FKBP65 messenger RNA. In summary, we have shown that FKBP65 is highly expressed in lung development, downregulated in the adult, and can be reactivated in a coordinated manner with extracellular matrix proteins after lung injury. The expression pattern of FKBP65, which is atypical for general ER foldases, suggests that FKBP65 has a distinct set of developmentally regulated protein ligands. The response to injury, which may be in part a direct response to TGF-beta1, assures the presence of FKBP65 in the ER of cells actively producing components of the extracellular matrix.

Interstitial expression of heat-shock protein 47 correlates with capillary deposition of complement split product C4d in chronic allograft nephropathy

BACKGROUND

Chronic allograft nephropathy (CAN), associated with late-allograft dysfunction is caused by alloantigen-dependent and -independent mechanisms, and eventually leads to interstitial fibrosis (ci). Activation of complement cascade is considered to be a poor prognostic marker of graft survival. This study was designed to examine the relationship between the expression of C4d and heat-shock protein 47 (HSP47, a collagen-specific chaperone) in the development of interstitial fibroproliferative lesions in CAN.

METHODS

Sixty-three renal allograft biopsy specimens, obtained from 48 patients, were examined for the expression of C4d, HSP47, CD68 and alpha-smooth muscle actin (alpha-SMA) by immunohistochemistry. Double-staining was performed to determine the colocalization of C4d and HSP47. The relationship of between the expression of C4d, HSP47, CD68 and alpha-SMA and the clinical and histopathological parameters were statistically analysed.

RESULTS

No expression of C4d was noted in the tubulointerstitium including peritubular capillary (PTC) of the control kidney. C4d was expressed in PTC in one-third of allograft renal tissues with morphological evidences of CAN. The interstitial cells around the fibrotic areas of the PTC of CAN were positive for the expression of HSP47. The deposition of C4d in PTC correlated with interstitial expression of HSP47 around the PTC. Most HSP47 expressing cells were phenotypically altered myofibroblasts, as determined by the dual staining of alpha-SMA.

CONCLUSIONS

The increased expression of HSP47 positively correlated with the expression of C4d in PTC, and might contribute to the progression of interstitial ci in CAN.

Number III Mucous membrane pemphigoid

Mucous membrane pemphigoid (MMP) is a sub-epithelial vesiculobullous disorder. It is now quite evident that a number of sub-epithelial vesiculobullous disorders may produce similar clinical pictures, and also that a range of variants of MMP exist, with antibodies directed against various hemidesmosomal components or components of the epithelial basement membrane. The term immune-mediated sub-epithelial blistering diseases (IMSEBD) has therefore been used. Immunological differences may account for the significant differences in their clinical presentation and responses to therapy, but unfortunately data on this are few. The diagnosis and management of IMSEBD on clinical grounds alone is impossible and a full history, general, and oral examination, and biopsy with immunostaining are now invariably required, sometimes supplemented with other investigations. No single treatment regimen reliably controls all these disorders, and it is not known if the specific subsets of MMP will respond to different drugs. Currently, apart from improving oral hygiene, immunomodulatory-especially immunosuppressive-therapy is typically used to control oral lesions. The present paper reviews pemphigoid, describing the present understanding of this fascinating clinical phenotype, summarising the increasing number of subsets with sometimes-different natural histories and immunological features, and outlining current clinical practice.

Identification of small molecule chemical inhibitors of the collagen-specific chaperone Hsp47

Hsp47 is a collagen-specific molecular chaperone whose activity has been implicated in the pathogenesis of fibrotic diseases. Here, we describe the development of an assay for screening libraries of chemical compounds for inhibitors of Hsp47. A preliminary screen of 2080 compounds identified four that demonstrated inhibitory activity against Hsp47 in vitro, with IC(50) values ranging from 3 to 27 muM. Compounds identified through this method may provide the basis for development of novel antifibrotic therapeutics.

Pulmonary fibrosis: cellular and molecular events

Connective tissue remodeling of the interstitium is an important feature of chronic lung diseases encompassing interstitial inflammatory changes and subsequent pulmonary fibrosis. The early inflammatory phase is usually associated with the release of several cytokines and chemokines by activated resident cells and infiltrating cells which, in turn, help further recruit inflammatory mononuclear cells. Cytokines and growth factors secreted by inflammatory cells and by interstitial cells (fibroblasts and myofibroblasts) play an important role in the fibrogenic phase of pulmonary fibrosis by inducing matrix synthesis. In addition, matrix-degrading enzymes and their inhibitors also contribute to extracellular matrix (ECM) remodeling in pulmonary fibrosis. This review addresses the pathophysiology of wound healing and different phases of pulmonary fibrosis.