Antisense oligonucleotide against collagen-specific molecular chaperone 47-kDa heat shock protein suppresses scar formation in rat wounds

Roles of the endoplasmic reticulum-resident, collagen-specific molecular chaperone Hsp47 in vertebrate cells and human disease

Heat shock protein 47 (Hsp47) is an endoplasmic reticulum (ER)-resident molecular chaperone essential for correct folding of procollagen in mammalian cells. In this Review, we discuss the role and function of Hsp47 in vertebrate cells and its role in connective tissue disorders. Hsp47 binds to collagenous (Gly-Xaa-Arg) repeats within triple-helical procollagen in the ER and can prevent its local unfolding or aggregate formation, resulting in accelerating triple-helix formation of procollagen. Hsp47 pH-dependently dissociates from procollagen in the cis-Golgi or ER-Golgi intermediate compartment and is then transported back to the ER. Although Hsp47 belongs to the serine protease inhibitor (serpin) superfamily, it does not possess serine protease inhibitory activity. Whereas general molecular chaperones such as Hsp70 and Hsp90 exhibit broad substrate specificity, Hsp47 has narrower specificity mainly for procollagens. However, other Hsp47-interacting proteins have been recently reported, suggesting a much broader role for Hsp47 in the cell that warrants further investigation. Other ER-resident stress proteins, such as binding immunoglobulin protein (BiP), are induced by ER stress, whereas Hsp47 is induced only by heat shock. Constitutive expression of Hsp47 is always correlated with expression of various collagen types, and disruption of the Hsp47 gene in mice causes embryonic lethality due to impaired basement membrane and collagen fibril formation. Increased Hsp47 expression is associated with collagen-related disorders such as fibrosis, characterized by abnormal collagen accumulation, highlighting Hsp47's potential as a clinically relevant therapeutic target.

Overexpression of miR-29b reduces collagen biosynthesis by inhibiting heat shock protein 47 during skin wound healing

Skin scar formation is characterized by excessive synthesis and aberrant deposition of collagens during wound healing. MicroRNAs are endogenous gene regulators critically involved in diverse biological events including skin scar formation and hold considerable promise as therapeutic targets. However, the detailed molecular mechanisms responsible for collagen production during skin wound repair and scar formation remain incompletely known. Here our data revealed that significant downregulation of miR-29b and upregulation of heat shock protein 47 (HSP47) were observed during wound healing in both excisional and burn wound models and also detected in facial skin scar as compared to adjacent healthy skin. HSP47, a specific chaperon for collagen production and secretion, was identified as a novel and direct post-transcriptional target of miR-29b in skin fibroblasts via bioinformatics prediction and experimental validation. Moreover, the regulatory functions of miR-29b in collagen biosynthesis are partially achieved through modulating HSP47 expression in skin fibroblasts. Furthermore, the profibrotic growth factor TGF-β1 inhibited miR-29b transcription by activating TGF-β/Smads signaling and in turn depressed HSP47 and enhanced collagen 1 production. In contrast, the proinflammatory cytokines IL-1β and TNF-α significantly induced miR-29b transcription via activating NF-κB signaling but had no significant effect on HSP47 and collagen production in skin fibroblasts. Importantly, local delivery of miR-29b lentiviral particles inhibited HSP47 expression and collagen biosynthesis as well as suppressed angiogenesis, thus reducing scar formation in an excisional wound splinting model. Collectively, our data reveal that miR-29b can reduce collagen biosynthesis during skin wound healing likely via post-transcriptional inhibition of HSP47 expression. These findings also suggest that therapeutic targeting of miR-29b/HSP47 might be a viable alternative strategy to prevent or reduce scar formation.

Interaction between Macrophages and Fibroblasts during Wound Healing of Burn Injuries in Rats

Analysis of the structural changes and cell-to-cell interactions occurring during wound healing of burn injuries is essential to elucidate the morphological characteristics of the reconstitution of tissue architecture. However, conventional approaches do not provide sufficient information with respect to cell-to-cell interactions during wound healing. The aim of this study was to evaluate the interaction between bone marrow-derived cells and resident stromal cells throughout the wound healing of burn injuries, using immunohistochemistry and focused ion beam/scanning electron microscope tomography. We induced third-degree burn injuries on the backs of Wistar rats with a heated cylindrical aluminum block (2.0 cm in diameter). At 7 and 14 days after the burn injuries, the burned skin was immunostained with anti-Iba1 and anti-HSP47 antibodies for visualization of bone marrow-derived cells/macrophages and resident stromal cells/fibroblasts, respectively. Normal skin tissue was used as a control. Double-staining immunohistochemistry revealed frequent contacts between macrophages and fibroblasts and a higher contact ratio in the 3 normal skin compared with burned skin, particularly in the areas of granuloma. Three-dimensional ultrastructural analysis with focused ion beam/scanning electron microscope tomography revealed that macrophages and fibroblasts were located closer together in the normal skin than in the burned skin, confirming the analysis by light microscopic observations and ultrastructural analysis from single sections. These results highlight the importance of contact between macrophages and fibroblasts in the maintenance of skin tissue structure and during wound healing.

Biologic activities of molecular chaperones and pharmacologic chaperone imidazole-containing dipeptide-based compounds: natural skin care help and the ultimate challenge: implication for adaptive responses in the skin

Accumulation of molecular damage and increased molecular heterogeneity are hallmarks of photoaged skin and pathogenesis of human cutaneous disease. Growing evidence demonstrates the ability of molecular chaperone proteins and of pharmacologic chaperones to decrease the environmental stress and ameliorate the oxidation stress-related and glycation disease phenotypes, suggesting that the field of chaperone therapy might hold novel treatments for skin diseases and aging. In this review, we examine the evidence suggesting a role for molecular chaperone proteins in the skin and their inducer and protecting agents: pharmacologic chaperone imidazole dipeptide-based agents (carcinine and related compounds) in cosmetics and dermatology. Furthermore, we discuss the use of chaperone therapy for the treatment of skin photoaging diseases and other skin pathologies that have a component of increased glycation and/or free radical-induced oxidation in their genesis. We examine biologic activities of molecular and pharmacologic chaperones, including strategies for identifying potential chaperone compounds and for experimentally demonstrating chaperone activity in in vitro and in vivo models of human skin disease. This allows the protein to function and traffic to the appropriate location in the skin, thereby increasing protein activity and cellular function and reducing stress on skin cells. The benefits of imidazole dipeptide antioxidants with transglycating activity (such as carcinine) in skin care are that they help protect and repair cell membrane damage and help retain youthful, younger-looking skin. All skin types will benefit from daily, topical application of pharmacologic chaperone antioxidants, anti-irritants, in combination with water-binding protein agents that work to mimic the structure and function of healthy skin. General strategies are presented addressing ground techniques to improve absorption of usually active chaperone proteins and dipeptide compounds, include encapsulation into hydrophobic carriers, a combination with penetration enhancers, active electrical transport, or chemical modification to increase hydrophobicity.

Creating thick linear scar by inserting a gelatin sponge into rat excisional wounds

The rat incisional wound is an important model for wound scarring research, but it is also difficult to mimic thick human incisional scarring. We hypothesized that such a thick linear scarring can be generated by inserting a gelatin sponge into a rat excisional wound. The results demonstrated that the new wound model could generate 11 times wider wound width (at day 7) and 4-5 times wider scar width (at days 14, 21, and 60), respectively, than the widths of incisional wounds (p<0.05) in adult Sprague-Dawley rats. The thick linear scar created was grossly apparent in contrast to the grossly unobvious scar of the incisional wound, and a regular linear shape could be achieved with a similar scar width along the wound. The mechanism study revealed several factors that might contribute to the enhanced scarring, including delayed wound healing, enhanced inflammation, increased expression of fibrotic factors, and abnormal wound remodeling due to the insertion of the gelatin sponge. These results indicate that the new wound model of thick linear scar might be valuable for clinically relevant study of scar manipulation. Moreover, this model may serve as a tool for studying gene-mediated tissue regeneration during wound repair using inserted gelatin sponge as a gene carrier.

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.

Effect of heat shock protein 47 on collagen accumulation in keloid fibroblast cells

BACKGROUND

Keloid is characterized by excessive collagen accumulation, but the mechanism of keloid formation remains unknown, and none of the treatment modalities are consistently effective. Heat shock protein (HSP) 47, known as a collagen-specific molecular chaperone, plays a critical role in collagen biosynthesis. Our previous research has demonstrated that HSP47 is highly expressed in keloid compared with normal skin tissues, which indicates that there might be a close relationship between overexpression of HSP47 and excessive collagen accumulation in keloid formation.

OBJECTIVES

To further investigate whether overexpression of HSP47 might promote excessive collagen deposition in keloid formation, we examined the alteration of intracellular and extracellular collagen expression, following inhibition of HSP47 expression in keloid fibroblast cells by the RNA interference technique.

METHODS

Three constructed psiRNA-hH1neo plasmids, carrying three pairs of related HSP47-shRNA (small hairpin RNA), respectively, were transfected into keloid fibroblast cells and compared with three control groups. After transfection, the mRNA and protein expression of HSP47 and collagen type I were detected by quantitative real-time polymerase chain reaction and Western blot; the content of extracellular secreting collagen was assessed by hydroxyproline assay; and the MTT [3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide] method was adopted to examine the proliferation of keloid fibroblast cells.

RESULTS

Both the mRNA and protein levels of HSP47 in keloid fibroblast cells decreased dramatically 48 h after post-transfection of three related HSP47-shRNA plasmids, compared with control groups. Following the downregulation of HSP47, we found that the expression of intracellular and extracellular collagen was correspondingly reduced. On the other hand, the MTT assay showed that transfection of HSP47-shRNA plasmids did not influence the growth of keloid fibroblast cells.

CONCLUSIONS

Combined with our previous histological results, we propose that overexpression of HSP47 in keloid fibroblast cells could induce excessive collagen accumulation by enhancing synthesis and secretion of collagen, which not only presents a possible mechanism of keloid formation, but also offers a therapeutic potential of RNA interference to HSP47 for the treatment of keloid and other fibroproliferative disorders.

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.

A bacterial reporter system for the evaluation of antisense oligodeoxynucleotides directed against human papillomavirus type 16 (HPV-16)

BACKGROUND

Antisense oligodeoxynucleotides (AS-ODNs) are a promising alternative for the cure of many diseases because of their in vivo specificity and stability. However, AS-ODNs have a strong dependence on the target mRNA structure making necessary extensive in vivo testing. There is, therefore, a need to develop assays to rapidly evaluate in vivo ODN performance.

METHODS

We report a simple and inexpensive bacterial reporter system for the rapid in vivo evaluation of AS-ODNs directed against human papillomavirus type 16 (HPV-16) based on the destruction of a chimeric CFP mRNA using the reported HPV-16 nt 410-445 target.

RESULTS

In vitro RNaseH assays confirmed target RNA accessibility after AS-ODN treatment. Expression of CFP in Escherichia coli BL21(DE3) with pGST-TSd2-CFP plasmid containing HPV-16 nt 410-445 target linked to CFP was blocked by transformed antisense PS-ODNs but not by two different scrambled ODN controls.

CONCLUSIONS

A correlation was observed between bacterial CFP downregulation with the HPV-16 E6/E7 mRNA downregulation and the inhibition of anchorage-independent growth of HPV-16 containing cells suggesting that inhibition of HPV-16 E6/E7 expression by AS-ODNs directed against 410-445 target in cervical tumor cells can be tested in bacterial models.

Prospective highlights of functional skin proteomics

Although a wide variety of protein profiles have been extensively constructed via proteomic analysis, the comprehensive proteomic profiling of the skin, which is considered to be the largest organ of the human body, is still far from complete. Our efforts to establish the functional skin proteome, a protein database describing the protein networks that underlie biological processes, has set in motion the identification and characterization of proteins expressed in the epidermis and dermis of the BALB/c mice. In this review, we will highlight various cutaneous proteins we have characterized and discuss their biological functions associated with skin distress, immunity, and cancer. This type of research into functional skin proteomics will provide a critical step toward understanding disease and developing successful therapeutic strategies.

Expression of HSP47, a collagen-specific chaperone, in normal and diseased human liver

HSP47 is a collagen-specific chaperone that is required for normal collagen synthesis. In animal models of liver injury, hepatic stellate cells (HSC) have been identified as a source of HSP47. Because expression of HSP47 has not been investigated in human liver, the aim of these studies was to characterize expression of HSP47 in human liver and to investigate its regulation in human HSC in vitro. Immunohistochemistry demonstrated staining for HSP47 along the sinusoids of normal and cirrhotic human livers and in fibrous septa. Dual fluorescence confocal microscopy showed colocalization of HSP47 with synaptophysin, a marker for HSC. Levels of immunoreactive HSP47 and its transcript tended to be higher in cirrhotic livers than in normal livers. The abundance of HSP47 protein was unchanged by treatment of cultured human HSC with TGF-beta1, angiotensin II, hypoxia and a number of other treatments intended to increase collagen synthesis. A modest reduction in HSP47 was achieved by transfection with antisense oligonucleotides and was associated with a significant decrease in procollagen synthesis. These observations suggest that HSP47 is constitutively expressed in human HSC and that HSP47 may be a target for antifibrotic therapy.

Wound healing-associated proteins Hsp47 and fibronectin are elevated in Dupuytren’s contracture

BACKGROUND

Dupuytren's contracture or disease (DD) affects hand function by causing irreversible contraction of the palmar fascia. Histological analysis has shown that DD and wound granulation tissue share many cellular and biochemical characteristics, suggesting that DD may be an exaggerated wound-healing response. The goal of the present study was to examine the possible involvement of two important wound-healing-associated proteins-heat shock protein 47 (Hsp47), fibronectin (Fn), and its oncofetal isoforms-in DD, using clinical tissue samples and primary cell cultures.

MATERIALS AND METHODS

We examined the expression of Hsp47, Fn, and an oncofetal isoform of fibronectin (IIICS) in both normal and disease-matched surgical specimens and primary cell cultures using Western blot analysis, and immunocytochemistry (ICC).

RESULTS

Our results indicate that Hsp47 and total fibronectin is elevated in DD lesional tissue. In addition, Western and ICC analysis of patient-matched (normal and disease) primary cultures show significantly elevated levels of oncofetal fibronectin (IIICS spliced variant) within disease primary cell cultures.

CONCLUSIONS

The high levels of expression of Hsp47 and adult and oncofetal fibronectin in DD suggests that cell-mediated alterations in the extracellular environment may play an important role in the disease process. Furthermore, the involvement of these wound healing-associated proteins in DD supports the notion that this disease may be an exaggerated form of wound healing.

HSP47 as a collagen-specific molecular chaperone: function and expression in normal mouse development

A large family of molecular chaperones can be divided into two major groups: general chaperone and substrate-specific chaperone. HSP47 is a collagen-specific molecular chaperone residing in the endoplasmic reticulum (ER). Recent studies revealed that HSP47 is essential molecular chaperone for mouse development and is essential for collagen molecular maturation in the ER. In the absence of HSP47, collagen microfibril formation and basement membrane formation are impaired in mouse embryos because the failure in the molecular maturation of types I and IV collagens, respectively. The tissue-specific expression of HSP47 is always correlated with that of various types of collagens and closely related with the collagen-related diseases including fibrosis in various organs. The importance of HSP47 in the therapeutic strategy for fibrotic diseases as well as for a marker of collagen-related autoimmune diseases will also be discussed.

Antisense oligonucleotide against 47-kDa heat shock protein (Hsp47) inhibits wound-induced enhancement of collagen production

It is well known that excessive collagen synthesis during the wound-healing process causes scar formation. Our recent in-vivo study indicates that antisense treatment against 47-kDa heat shock protein (Hsp47), a collagen-specific molecular chaperone, relieves scar formation following skin wounds in rats [Wang et al., Plast. Reconstr. Surg., in press]. In order to understand the mechanism of this phenomenon, we examined the effects of antisense treatment on the expression of mRNAs and proteins of Hsp47 and collagens in fibroblasts derived from wounded rat tongues. Hsp47 and procollagen alpha1(I) and alpha1(III) mRNAs were consistently increased after wounding and were maximal at day 5 post-injury. Treatment with antisense oligonucleotide against Hsp47 efficiently blocked the production of procollagen alpha2(I) and alpha1(III) proteins, but had little effect on their mRNA levels. Therefore, we conclude that antisense oligonucleotide against Hsp47 inhibits the production of procollagen type I and III proteins in fibroblasts derived from wounded tongues, overcoming the increase in their mRNAs.