Hsp47: a collagen-specific molecular chaperone

Proteomic Heterogeneity of the Extracellular Matrix Identifies Histologic Subtype-Specific Fibroblast in Gastric Cancer

Gastric cancer (GC) is a highly heterogeneous disease regarding histologic features, genotypes, and molecular phenotypes. Here, we investigate extracellular matrix (ECM)-centric analysis, examining its association with histologic subtypes and patient prognosis in human GC. We performed quantitative proteomic analysis of decellularized GC tissues that characterizes tumorous ECM, highlighting proteomic heterogeneity in ECM components. We identified 20 tumor-enriched proteins including four glycoproteins, serpin family H member 1 (SERPINH1), annexin family (ANXA3/4/5/13), S100A family (S100A6/8/9), MMP14, and other matrisome-associated proteins. In addition, histopathological characteristics of GC reveals differential expression in ECM composition, with the poorly cohesive carcinoma-not otherwise specified (PCC-NOS) subtype being distinctly demarcated from other histologic subtypes. Integrating ECM proteomics with single-cell RNA sequencing, we identified crucial molecular markers in the PCC-NOS-specific stroma. PCC-NOS-enriched matrisome proteins and gene expression signatures of adipogenic cancer-associated fibroblasts (CAFadi) are closely linked, both associated with adverse outcomes in GC. Using tumor microarray analysis, we confirmed the CAFadi surface marker, ATP binding cassette subfamily A member 8 (ABCA8), predominantly present in PCC-NOS tumors. Our ECM-focused analysis paves the way for studies to determine their utility as biomarkers for patient stratification, offering valuable insights for linking molecular and histologic features in GC.

Oligonucleotide therapies for nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) represents a severe disease subtype of nonalcoholic fatty liver disease (NAFLD) that is thought to be highly associated with systemic metabolic abnormalities. It is characterized by a series of substantial liver damage, including hepatocellular steatosis, inflammation, and fibrosis. The end stage of NASH, in some cases, may result in cirrhosis and hepatocellular carcinoma (HCC). Nowadays a large number of investigations are actively under way to test various therapeutic strategies, including emerging oligonucleotide drugs (e.g., antisense oligonucleotide, small interfering RNA, microRNA, mimic/inhibitor RNA, and small activating RNA) that have shown high potential in treating this fatal liver disease. This article systematically reviews the pathogenesis of NASH/NAFLD, the promising druggable targets proven by current studies in chemical compounds or biological drug development, and the feasibility and limitations of oligonucleotide-based therapeutic approaches under clinical or pre-clinical studies.

Specific localization of fibroblasts at the intercalated duct in the major salivary glands of rats

OBJECTIVES

Immunohistochemical methods were employed to investigate the morphological heterogeneity and localization of fibroblasts associated with the function of major salivary glands in rats.

METHODS

Histochemical and electron microscopic observations were made in rat parotid, submandibular, and sublingual glands and pancreas. Fibroblasts were immunostained using their specific marker, 47 kDa heat shock protein (Hsp47).

RESULTS

Hsp47-immunopositive fibroblasts within the intralobular connective tissue exhibited a notably smaller size compared with the interlobular connective tissue. They were loosely distributed throughout the connective tissue. However, fibroblasts with elongated long processes were explicitly identified at the intercalated ducts in parotid, sublingual, and submandibular glands. Fibroblastic bodies and processes were tightly approximated with the basement membrane of the duct. Electron microscopy confirmed these findings, revealing a thin layer consisting of collagen fibers was found between the fibroblasts and the basement membrane. Double staining of Hsp47 and α-smooth muscle actin (αSMA) in parotid glands indicating that Hsp47-positive fibroblasts enveloped both the duct and αSMA-positive myoepithelial cells. Additionally, They projected long and thin processes longitudinally at the straight portion or circularly at the bifurcated portion of the duct. The three-dimensional reconstruction showed a frame-like structure of fibroblasts surrounding the intercalated duct with longitudinal myoepithelial cells. However, such specific localization of fibroblasts was not detected in the exocrine pancreas lacking myoepithelium.

CONCLUSIONS

Small fibroblasts with long processes connecting or overwrapping each other and thin collagen layers surround the intercalated ducts in rat major salivary glands, presumably contributing to protecting the ducts from salivary flow and myoepithelial contraction.

Characterization and transcript expression analyses of four Atlantic salmon (Salmo salar) serpinh1 paralogues provide evidence of evolutionary divergence

Atlantic salmon (Salmo salar) are not only the world's most economically important farmed fish in terms of total value, but also a salmonid, which means that they are invaluable for studies of the evolutionary fate of genes following multiple whole-genome duplication (WGD) events. In this study, four paralogues of the molecular chaperone serpinh1 were characterized in Atlantic salmon, as while this gene is considered to be a sensitive biomarker of heat stress in salmonids, mammalian studies have also identified it as being essential for collagen structural assembly and integrity. The four salmon paralogues were cloned and sequenced so that in silico analyses at the nucleotide and deduced amino acid levels could be performed. In addition, qPCR was used to measure: paralogue- and sex-specific constitutive serpinh1 expression across 17 adult tissues; and their expression in the liver and head kidney of male Atlantic salmon as affected by stress phenotype (high vs. low responder), increased temperature, and injection with a multi-valent vaccine. Compared to the other three paralogues, serpinh1a-2 had a unique constitutive expression profile across the 17 tissues. Although stress phenotype had minimal impact on the transcript expression of the four paralogues, injection with a commercial vaccine containing several formalin inactivated bacterins increased the expression of most paralogues (by 1.1 to 4.5-fold) across both tissues. At 20 °C, the expression levels of serpinh1a-1 and serpinh1a-2 were generally lower (by -1.1- to -1.6-fold), and serpinh1b-1 and serpinh1b-2 were 10.2- to 19.0-fold greater, in comparison to salmon held at 12 °C. With recent studies suggesting a putative link between serpinh1 and upper thermal tolerance in salmonids, the current research is a valuable first step in elucidating the potential mechanisms involved. This research: supports the use of serpinh1b-1 and serpinh1b-2 as a biomarkers of heat stress in salmon; and provides evidence of neo- and/or subfunctionalization between the paralogues, and important insights into how multiple genome duplication events can potentially lead to evolutionary divergence.

Modulating Golgi Stress Signaling Ameliorates Cell Morphological Phenotypes Induced by CHMP2B with Frontotemporal Dementia-Associated p.Asp148Tyr

Some charged multivesicular body protein 2B (CHMP2B) mutations are associated with autosomal-dominant neurodegenerative frontotemporal dementia and/or amyotrophic lateral sclerosis type 7 (FTDALS7). The main aim of this study is to clarify the relationship between the expression of mutated CHMP2B protein displaying FTD symptoms and defective neuronal differentiation. First, we illustrate that the expression of CHMP2B with the Asp148Tyr (D148Y) mutation, which preferentially displays FTD phenotypes, blunts neurite process elongation in rat primary cortical neurons. Similar results were observed in the N1E-115 cell line, a model that undergoes neurite elongation. Second, these effects were also accompanied by changes in neuronal differentiation marker protein expression. Third, wild-type CHMP2B protein was indeed localized in the endosomal sorting complexes required to transport (ESCRT)-like structures throughout the cytoplasm. In contrast, CHMP2B with the D148Y mutation exhibited aggregation-like structures and accumulated in the Golgi body. Fourth, among currently known Golgi stress regulators, the expression levels of Hsp47, which has protective effects on the Golgi body, were decreased in cells expressing CHMP2B with the D148Y mutation. Fifth, Arf4, another Golgi stress-signaling molecule, was increased in mutant-expressing cells. Finally, when transfecting Hsp47 or knocking down Arf4 with small interfering (si)RNA, cellular phenotypes in mutant-expressing cells were recovered. These results suggest that CHMP2B with the D148Y mutation, acting through Golgi stress signaling, is negatively involved in the regulation of neuronal cell morphological differentiation, providing evidence that a molecule controlling Golgi stress may be one of the potential FTD therapeutic targets at the molecular and cellular levels.

Collagen in the central nervous system: contributions to neurodegeneration and promise as a therapeutic target

The extracellular matrix is a richly bioactive composition of substrates that provides biophysical stability, facilitates intercellular signaling, and both reflects and governs the physiological status of the local microenvironment. The matrix in the central nervous system (CNS) is far from simply an inert scaffold for mechanical support, instead conducting an active role in homeostasis and providing broad capacity for adaptation and remodeling in response to stress that otherwise would challenge equilibrium between neuronal, glial, and vascular elements. A major constituent is collagen, whose characteristic triple helical structure renders mechanical and biochemical stability to enable bidirectional crosstalk between matrix and resident cells. Multiple members of the collagen superfamily are critical to neuronal maturation and circuit formation, axon guidance, and synaptogenesis in the brain. In mature tissue, collagen interacts with other fibrous proteins and glycoproteins to sustain a three-dimensional medium through which complex networks of cells can communicate. While critical for matrix scaffolding, collagen in the CNS is also highly dynamic, with multiple binding sites for partnering matrix proteins, cell-surface receptors, and other ligands. These interactions are emerging as critical mediators of CNS disease and injury, particularly regarding changes in matrix stiffness, astrocyte recruitment and reactivity, and pro-inflammatory signaling in local microenvironments. Changes in the structure and/or deposition of collagen impact cellular signaling and tissue biomechanics in the brain, which in turn can alter cellular responses including antigenicity, angiogenesis, gliosis, and recruitment of immune-related cells. These factors, each involving matrix collagen, contribute to the limited capacity for regeneration of CNS tissue. Emerging therapeutics that attempt to rebuild the matrix using peptide fragments, including collagen-enriched scaffolds and mimetics, hold great potential to promote neural repair and regeneration. Recent evidence from our group and others indicates that repairing protease-degraded collagen helices with mimetic peptides helps restore CNS tissue and promote neuronal survival in a broad spectrum of degenerative conditions. Restoration likely involves bolstering matrix stiffness to reduce the potential for astrocyte reactivity and local inflammation as well as repairing inhibitory binding sites for immune-signaling ligands. Facilitating repair rather than endogenous replacement of collagen degraded by disease or injury may represent the next frontier in developing therapies based on protection, repair, and regeneration of neurons in the central nervous system.

Serpin family H member 1 and its related collagen gene network are the potential prognostic biomarkers and anticancer targets for glioma

Serpin family H member 1 (SERPINH1) is responsible for encoding the protein known as heat shock protein 47, which functions as a molecular chaperone specific to collagen (COL). This protein has been identified as a potential therapeutic target for COL-related disorders. In this study, we aimed to investigate the role of SERPINH1 in the tumorigenicity of gliomas. To achieve this, we utilized various bioinformatics tools to analyze gene expression, overall survival, protein-protein interactions, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, and Gene Set Enrichment Analysis (GSEA). Based on The Cancer Genome Atlas database revealed that SERPINH1 and four COL family members (COL1A1, COL3A1, COL4A1, and COL4A2) expression are significantly upregulated in glioma tissues compared with normal nontumor tissues. GO, KEGG, and GSEA analyses exhibited that SERPINH1 is implicated in the establishment and degradation of COL-containing extracellular matrix (ECM), focal adhesion, and ECM-receptor interaction in glioma. SERPINH1 is an independent prognostic factor, exhibiting a positive association with the augmentation of neutrophils and macrophages, as well as the manifestation of immune checkpoint molecules within glioma. Experimental assessments conducted both in vitro and in vivo demonstrated that the suppression of SERPINH1 impeded the migratory, invasive, and proliferative capacities of glioma cells, while concurrently fostering cellular apoptosis. Consequently, SERPINH1 emerges as an oncogenic gene and an independent prognostic marker for glioma, potentially facilitating the advancement of immunotherapeutic interventions for the treatment of glioma.

SERPINH1 enhances the malignancy of osteosarcoma via PI3K-Akt signaling pathway

BACKGROUND

Serpin Family H Member 1 (SERPINH1) may be involved in the regulation of occurrence and development of tumors. However, the role and mechanism of SERPINH1 in osteosarcoma remain poorly understood. The aim of this study is to investigate the expression and role of SRPINH1 in osteosarcoma and to elucidate its underlying mechanisms.

METHODS

First, we examined the expression of SERPINH1 in osteosarcoma and analyzed publicly available datasets to investigate whether SERPINH1 expression was associated with the prognosis of osteosarcoma. Then we constructed SERPINH1 overexpression and knockdown systems in osteosarcoma cells, and examined the proliferation, migration and invasion ability of osteosarcoma cells after SERPINH1 expression changes using CCK-8 assay, wound healing assay and transwell invasion assay. In addition, we constructed a subcutaneous xenograft tumor model to study the function of SERPINH1 in vivo. We also examined the downstream pathways of SERPINH1 by functional analysis and performed subsequent validation.

RESULTS

SERPINH1 was upregulated and associated with poor survival in patients with osteosarcoma. SERPINH1 promoted the proliferation, migration and invasion of osteosarcoma cells and promotes the growth of osteosarcoma in vivo by activating the PI3K-Akt signaling pathway.

CONCLUSION

SERPINH1 partakes in the biological process of osteosarcoma as a tumor promotor and may be an emerging biomarker in osteosarcoma.

HSP47 levels determine the degree of body adiposity

Adiposity varies among individuals with the influence of diverse physiological, pathological, environmental, hormonal, and genetic factors, but a unified molecular basis remains elusive. Here, we identify HSP47, a collagen-specific chaperone, as a key determinant of body adiposity. HSP47 expression is abundant in adipose tissue; increased with feeding, overeating, and obesity; decreased with fasting, exercise, calorie restriction, bariatric surgery, and cachexia; and correlated with fat mass, BMI, waist, and hip circumferences. Insulin and glucocorticoids, respectively, up- and down-regulate HSP47 expression. In humans, the increase of HSP47 gene expression by its intron or synonymous variants is associated with higher body adiposity traits. In mice, the adipose-specific knockout or pharmacological inhibition of HSP47 leads to lower body adiposity compared to the control. Mechanistically, HSP47 promotes collagen dynamics in the folding, secretion, and interaction with integrin, which activates FAK signaling and preserves PPARγ protein from proteasomal degradation, partly related to MDM2. The study highlights the significance of HSP47 in determining the amount of body fat individually and under various circumstances.

Role of heat shock protein 47 in platelet glycoprotein VI dimerization and signaling

Background

Heat shock protein 47 (HSP47) is an intracellular chaperone protein with an indispensable role in collagen biosynthesis in collagen-secreting cells. This chaperone has also been shown to be released and present on the surface of platelets. The inhibition of HSP47 in human platelets or its ablation in mouse platelets reduces platelet function in response to collagen and the glycoprotein (GP) VI collagen receptor agonist CRP-XL.

Objectives

In this study, we sought, through experiments, to explore cellular distribution, trafficking, and influence on GPVI interactions to understand how HSP47 modulates collagen receptor signaling.

Methods

HSP47-deficient mouse platelets and SMIH- treated human platelets were used to study the role of HSP47 in collagen mediated responses and signaling.

Results

Using subcellular fractionation analysis and immunofluorescence microscopy, HSP47 was found to be localized to the platelet-dense tubular system. Following platelet stimulation, HSP47 mobilization to the cell surface was shown to be dependent on actin polymerization, a feature common to other dense tubular system resident platelet proteins that are released to the cell surface during activation. In this location, HSP47 was found to contribute to platelet adhesion to collagen or CRP-XL but not to GFOGER peptide (an integrin α2β1-binding sequence within collagens), indicating selective effects of HSP47 on GPVI function. Dimerization of GPVI on the platelet surface increases its affinity for collagen. GPVI dimerization was reduced following HSP47 inhibition, as was collagen and CRP-XL-mediated signaling.

Conclusion

The present study identifies a role for cell surface-localized HSP47 in modulating platelet responses to collagen through dimerization of GPVI, thereby enhancing platelet signaling and activation.

Preventative Effects of Cordyceps cicadae Mycelial Extracts on the Early-Stage Development of Cataracts in UVB-Induced Mice Cataract Model

Cataracts, a prevalent age-related eye condition, pose a significant global health concern, with rising rates due to an aging population and increased digital device usage. In Taiwan, cataract prevalence is particularly high, reaching up to 90% among individuals aged 70 and above. The lens of the eye absorbs short-wave light, which can lead to oxidative stress in lens epithelial cells and contribute to cataract formation. Exposure to ultraviolet (UV) light further exacerbates the risk of cataracts by generating reactive oxygen species. Heat-shock proteins (HSPs), involved in protein maintenance and repair, have been linked to cataract development. Cordyceps cicadae (C. cicadae), a traditional Chinese medicine, has a long history of use and is known for its pharmacological effects. N6-(2-hydroxyethyl) adenosine (HEA), a bioactive compound found in C. cicadae, exhibits anti-inflammatory, immunomodulatory, and neuroprotective properties. Previous studies have shown that C. cicadae mycelial extracts improve dry eye disease and reduce intraocular pressure in animal models. Additionally, C. cicadae possesses antioxidant properties, which are beneficial for combating cataract formation. In this study, we aim to evaluate the preventive efficacy of C. cicadae mycelial extracts in UV-induced cataract development. By investigating the ameliorative effects of C. cicadae on eye diseases and its potential role in ocular health improvement, we hope to uncover new options for cataract prevention and provide insights into the mechanisms of action. The findings of this research could provide a novel approach for nutritional supplements targeting cataract prevention, offering potential benefits in the field of ocular health.

Interplay between calcium and endoplasmic reticulum stress

Cellular homeostasis is crucial for the healthy functioning of the organism. Disruption of cellular homeostasis activates endoplasmic reticulum (ER) stress coping responses including the unfolded protein response (UPR). There are three ER resident stress sensors responsible for UPR activation - IRE1α, PERK and ATF6. Ca²⁺ signaling plays an important role in stress responses including the UPR and the ER is the main Ca²⁺ storage organelle and a source of Ca²⁺ for cell signaling. The ER contains many proteins involved in Ca²⁺ import/export/ storage, Ca²⁺ movement between different cellular organelles and ER Ca²⁺ stores refilling. Here we focus on selected aspects of ER Ca²⁺ homeostasis and its role in activation of the ER stress coping responses.

Morphologic and molecular biologic analyses of the skin rejuvenation effect of the fractional 1064-nm picosecond laser: An animal study

OBJECTIVES

Application of the picosecond laser in the field of dermatology has expanded from tattoo removal to skin rejuvenation on a clinical basis. Although various mechanisms of pigment removal have been elucidated, the molecular changes associated with skin rejuvenation have yet to be identified. The aim of this study was to explore the theoretical basis and to evaluate the efficacy of skin rejuvenation using a 1064-nm fractional picosecond laser in a mouse model.

METHODS

We conducted an in vivo study using a fractional picosecond laser on the skin of old and young female hairless mice and performed topographical, histological, micro-, and electron microscopic assessments.

RESULTS

The topography of the skin surface was enhanced and showed increased dermal thickness on histological examination. Electron microscopy revealed disarranged collagen bundles with microspaces and vascular leakage in the upper dermis. Levels of collagen synthesis markers and various inflammatory cytokines, such as procollagens, interleukin-1β, tumor necrosis factor-α, and heat shock proteins, were elevated in the laser-treated skin.

CONCLUSIONS

This study provides a possible mechanism for the skin rejuvenation effect of fractional picosecond laser that has been reported previously in clinical observations. Based on our findings, the fractional picosecond laser could be widely applied in clinical settings where dermal regeneration and promotion of skin rejuvenation is required.

Optimization of an Ex-Vivo Human Skin/Vein Model for Long-Term Wound Healing Studies: Ground Preparatory Activities for the 'Suture in Space' Experiment Onboard the International Space Station

This study is preliminary to an experiment to be performed onboard the International Space Station (ISS) and on Earth to investigate how low gravity influences the healing of sutured human skin and vein wounds. Its objective was to ascertain whether these tissue explants could be maintained to be viable ex vivo for long periods of time, mimicking the experimental conditions onboard the ISS. We developed an automated tissue culture chamber, reproducing and monitoring the physiological tensile forces over time, and a culture medium enriched with serelaxin (60 ng/mL) and (Zn(PipNONO)Cl) (28 ng/mL), known to extend viability of explanted organs for transplantation. The results show that the human skin and vein specimens remained viable for more than 4 weeks, with no substantial signs of damage in their tissues and cells. As a further clue about cell viability, some typical events associated with wound repair were observed in the tissue areas close to the wound, namely remodeling of collagen fibers in the papillary dermis and of elastic fibers in the vein wall, proliferation of keratinocyte stem cells, and expression of the endothelial functional markers eNOS and FGF-2. These findings validate the suitability of this new ex vivo organ culture system for wound healing studies, not only for the scheduled space experiment but also for applications on Earth, such as drug discovery purposes.

The Molecular Mechanisms of Liver Fibrosis and Its Potential Therapy in Application

Liver fibrosis results from repeated and persistent liver damage. It can start with hepatocyte injury and advance to inflammation, which recruits and activates additional liver immune cells, leading to the activation of the hepatic stellate cells (HSCs). It is the primary source of myofibroblasts (MFs), which result in collagen synthesis and extracellular matrix protein accumulation. Although there is no FDA and EMA-approved anti-fibrotic drug, antiviral therapy has made remarkable progress in preventing or even reversing the progression of liver fibrosis, but such a strategy remains elusive for patients with viral, alcoholic or nonalcoholic steatosis, genetic or autoimmune liver disease. Due to the complexity of the etiology, combination treatments affecting two or more targets are likely to be required. Here, we review the pathogenic mechanisms of liver fibrosis and signaling pathways involved, as well as various molecular targets for liver fibrosis treatment. The development of efficient drug delivery systems that target different cells in liver fibrosis therapy is also summarized. We highlight promising anti-fibrotic events in clinical trial and preclinical testing, which include small molecules and natural compounds. Last, we discuss the challenges and opportunities in developing anti-fibrotic therapies.

Characterization of the Skeletal Muscle Proteome in Undernourished Old Rats

Aging is associated with a progressive loss of skeletal muscle mass and function termed sarcopenia. Various metabolic alterations that occur with aging also increase the risk of undernutrition, which can worsen age-related sarcopenia. However, the impact of undernutrition on aged skeletal muscle remains largely under-researched. To build a deeper understanding of the cellular and molecular mechanisms underlying age-related sarcopenia, we characterized the undernutrition-induced changes in the skeletal muscle proteome in old rats. For this study, 20-month-old male rats were fed 50% or 100% of their spontaneous intake for 12 weeks, and proteomic analysis was performed on both slow- and fast-twitch muscles. Proteomic profiling of undernourished aged skeletal muscle revealed that undernutrition has profound effects on muscle proteome independently of its effect on muscle mass. Undernutrition-induced changes in muscle proteome appear to be muscle-type-specific: slow-twitch muscle showed a broad pattern of differential expression in proteins important for energy metabolism, whereas fast-twitch muscle mainly showed changes in protein turnover between undernourished and control rats. This first proteomic analysis of undernourished aged skeletal muscle provides new molecular-level insight to explain phenotypic changes in undernourished aged muscle. We anticipate this work as a starting point to define new biomarkers associated with undernutrition-induced muscle loss in the elderly.

Therapeutic targets, novel drugs, and delivery systems for diabetes associated NAFLD and liver fibrosis

Type 2 diabetes mellitus (T2DM) associated non-alcoholic fatty liver disease (NAFLD) is the fourth-leading cause of death. Hyperglycemia induces various complications, including nephropathy, cirrhosis and eventually hepatocellular carcinoma (HCC). There are several etiological factors leading to liver disease development, which involve insulin resistance and oxidative stress. Free fatty acid (FFA) accumulation in the liver exerts oxidative and endoplasmic reticulum (ER) stresses. Hepatocyte injury induces release of inflammatory cytokines from Kupffer cells (KCs), which are responsible for activating hepatic stellate cells (HSCs). In this review, we will discuss various molecular targets for treating chronic liver diseases, including homeostasis of FFA, lipid metabolism, and decrease in hepatocyte apoptosis, role of growth factors, and regulation of epithelial-to-mesenchymal transition (EMT) and HSC activation. This review will also critically assess different strategies to enhance drug delivery to different cell types. Targeting nanocarriers to specific liver cell types have the potential to increase efficacy and suppress off-target effects.

Structural and biochemical characterization of the novel serpin Iripin-5 from Ixodes ricinus

Iripin-5 is the main Ixodes ricinus salivary serpin, which acts as a modulator of host defence mechanisms by impairing neutrophil migration, suppressing nitric oxide production by macrophages and altering complement functions. Iripin-5 influences host immunity and shows high expression in the salivary glands. Here, the crystal structure of Iripin-5 in the most thermodynamically stable state of serpins is described. In the reactive-centre loop, the main substrate-recognition site of Iripin-5 is likely to be represented by Arg342, which implies the targeting of trypsin-like proteases. Furthermore, a computational structural analysis of selected Iripin-5-protease complexes together with interface analysis revealed the most probable residues of Iripin-5 involved in complex formation.

SERPINA11 Inhibits Metastasis in Hepatocellular Carcinoma by Suppressing MEK/ERK Signaling Pathway

Purpose

By using integrative RNA sequencing analysis, we identified a novel tumor suppressor, serpin family A member 11 (SERPINA11), which is a serine proteinase inhibitor that belongs to the serpin superfamily. However, the function of SERPINA11 in hepatocellular carcinoma (HCC) remains unclear. The aim of this study was to investigate the role and molecular mechanism of SERPINA11 in HCC.

Methods

Gene expression patterns of SERPINA11 were analyzed in tissue samples of HCC patients by qRT-PCR. In vitro and in vivo experiments were performed to characterize the function and molecular mechanism of SERPINA11 in the tumor metastasis capacity.

Results

SERPINA11 was downregulated in approximately 50% of HCC and significantly associated with metastasis and poor outcome of patients. Functional study demonstrated that SERPINA11 could inhibit cell growth, cell migration and tumor metastasis. Mechanistic investigations suggested that SERPINA11 accelerated urokinase-type plasminogen activator (uPA) degradation to suppress extracellular signal-regulated kinase (ERK1/2) phosphorylation, and thereby subdued metastatic capabilities of HCC cells.

Conclusion

SERPINA11 plays an important tumor suppressive role in HCC, with possible use as a biomarker and an intervention point for new therapeutic strategies.

Aberrant binding of mutant HSP47 affects posttranslational modification of type I collagen and leads to osteogenesis imperfecta

Heat shock protein 47 (HSP47), encoded by the SERPINH1 gene, is a molecular chaperone essential for correct folding of collagens. We report a homozygous p.(R222S) substitution in HSP47 in a child with severe osteogenesis imperfecta leading to early demise. p.R222 is a highly conserved residue located within the collagen interacting surface of HSP47. Binding assays show a significantly reduced affinity of HSP47-R222S for type I collagen. This altered interaction leads to posttranslational overmodification of type I procollagen produced by dermal fibroblasts, with increased glycosylation and/or hydroxylation of lysine and proline residues as shown by mass spectrometry. Since we also observed a normal intracellular folding and secretion rate of type I procollagen, this overmodification cannot be explained by prolonged exposure of the procollagen molecules to the modifying hydroxyl- and glycosyltransferases, as is commonly observed in other types of OI. We found significant upregulation of several molecular chaperones and enzymes involved in procollagen modification and folding on Western blot and RT-qPCR. In addition, we showed that an imbalance in binding of HSP47-R222S to unfolded type I collagen chains in a gelatin sepharose pulldown assay results in increased binding of other chaperones and modifying enzymes. The elevated expression and binding of this molecular ensemble to type I procollagen suggests a compensatory mechanism for the aberrant binding of HSP47-R222S, eventually leading to overmodification of type I procollagen chains. Together, these results illustrate the importance of HSP47 for proper posttranslational modification and provide insights into the molecular pathomechanisms of the p.(R222S) alteration in HSP47, which leads to a severe OI phenotype.

Heat shock protein 47 (HSP47) is essential for correct collagen folding. We report a homozygous p.(R222S) substitution in HSP47 in a child with severe osteogenesis imperfecta. The highly conserved p.R222 residue is located within the collagen interacting surface and HSP47-R222S shows a significantly reduced affinity for type I collagen. This altered interaction leads to posttranslational overmodification of type I procollagen. In contrast to other types of OI, this overmodification is not caused by prolonged exposure of procollagen to modifying enzymes, since the intracellular folding rate of type I procollagen appears to be normal. We show significant upregulation of several molecular chaperones and collagen-modifying enzymes and increased binding of several of these molecules to unfolded type I collagen chains upon abnormal HSP47-R222S binding. This suggests a compensatory mechanism for aberrant HSP47-R222S binding, eventually leading to overmodification of type I procollagen chains, and underscores the importance of HSP47 for proper posttranslational modification.

Targeting PAI-1 in Cardiovascular Disease: Structural Insights Into PAI-1 Functionality and Inhibition

Plasminogen activator inhibitor-1 (PAI-1), a member of the serine protease inhibitor (serpin) superfamily with antiprotease activity, is the main physiological inhibitor of tissue-type (tPA) and urokinase-type (uPA) plasminogen activators (PAs). Apart from being crucially involved in fibrinolysis and wound healing, PAI-1 plays a pivotal role in various acute and chronic pathophysiological processes, including cardiovascular disease, tissue fibrosis, cancer, and age-related diseases. In the prospect of treating the broad range of PAI-1-related pathologies, many efforts have been devoted to developing PAI-1 inhibitors. The use of these inhibitors, including low molecular weight molecules, peptides, antibodies, and antibody fragments, in various animal disease models has provided ample evidence of their beneficial effect in vivo and moved forward some of these inhibitors in clinical trials. However, none of these inhibitors is currently approved for therapeutic use in humans, mainly due to selectivity and toxicity issues. Furthermore, the conformational plasticity of PAI-1, which is unique among serpins, poses a real challenge in the identification and development of PAI-1 inhibitors. This review will provide an overview of the structural insights into PAI-1 functionality and modulation thereof and will highlight diverse approaches to inhibit PAI-1 activity.

Genome Wide Identification and Comparative Analysis of the Serpin Gene Family in Brachypodium and Barley

Serpins (serine protease inhibitors) constitute one of the largest and most widely distributed superfamilies of protease inhibitors and have been identified in nearly all organisms. To gain significant insights, a comprehensive in silico analysis of the serpin gene family was carried out in the model plant for temperate grasses Brachypodium distachyon and barley Hordeum vulgare using bioinformatic tools at the genome level for the first time. We identified a total of 27 BdSRPs and 25 HvSRP genes in Brachypodium and barley, respectively, showing an unexpectedly high gene number in these model plants. Gene structure, conserved motifs and phylogenetic comparisons of serpin genes supported the role of duplication events in the expansion and evolution of serpin gene family. Further, purifying selection pressure was found to be a main driving force in the evolution of serpin genes. Genome synteny analysis indicated that BdSRP genes were present in syntenic regions of barley, rice, sorghum and maize, suggesting that they evolved before the divergence of these species from common ancestor. The distinct expression pattern in specific tissues further suggested a specialization of functions during development and in plant defense. These results suggest that the LR serpins (serpins with Leu-Arg residues at P2-P1') identified here can be utilized as candidates for exploitation in disease resistance, pest control and preventing stress-induced cell death. Additionally, serpins were identified that could lead to further research aimed at validating and functionally characterizing the role of potential serpin genes from other plants.

Xiaochaihu decorction relieves liver fibrosis caused by Schistosoma japonicum infection via the HSP47/TGF-β pathway

Background

Hepatic fibrosis caused by chronic infection with Schistosoma japonica remains a serious public health problem in the world. Symptoms include inflammation, liver granuloma and fibrosis, whilst treatment options are still limited. This study aims to investigate whether and how traditional Chinese medicine Xiaochaihu decoction (XCH) could mitigate liver fibrosis caused by S. japonicum infection.

Methods

BALB/c mice were infected with S. japonicum cercariae and treated with XCH for 16 weeks. Liver pathological changes were assessed by H&E and Masson staining. NIH3T3 and Raw264.7 cells were treated with S. japonicum egg antigens with or without XCH treatment. Quantitative real-time PCR, western blot, immunfluorescence and ELISA were performed to determine the changes of levels of fibrogenic markers.

Results

XCH protected mouse liver from injuries and fibrosis caused by S. japonicum infection and considerably reduced egg burden in a dose-dependent manner. Infection with S. japonicum caused elevation of serum ALT, AST, ALP, HA and PIIINP levels and reduction of ALB and GLOB levels, which was markedly suppressed by XCH. The upregulation of TGF-β1, Hsp47, α-SMA, Col1A1 and Col3A1 in S. japonicum-infected mouse liver was also significantly inhibited by XCH. Schistosoma japonicum egg antigens promoted the expression of Hsp47, TGF-β1, Timp-1, α-SMA, Col1A1 and Col3A1 in NIH3T3 cells, and TGF-β1, CTGF, IL-13, IL-17 and IL-6 in Raw264.7 cells, which was inhibited by XCH, LY2157299 and shRNA-Hsp47.

Conclusions

These results demonstrated that the hepatic protective effects of Xiaochaihu decoction were mediated by HSP47/TGF-β axis.

Chaperone potential of erythroid spectrin: Effects of hemoglobin interaction, macromolecular crowders, phosphorylation and glycation

Spectrin, the major protein component of the erythrocyte membrane skeleton has chaperone like activity and is known to bind membrane phospholipids and hemoglobin. We have probed the chaperone activity of spectrin in presence of hemoglobin and phospholipid SUVs of different compositions to elucidate the effect of phospholipid/hemoglobin binding on chaperone function. It is seen that spectrin displays a preference for hemoglobin over other substrates leading to a decrease in chaperone activity in presence of hemoglobin. A competition is seen to exist between phospholipid binding and chaperone function of spectrin, in a dose dependent manner with the greatest extent of decrease being seen in case of phospholipid vesicles containing aminophospholipids e.g. PS and PE which may have implications in diseases like hereditary spherocytosis where mutation in spectrin is implicated in its detachment from cell membrane. To gain a clearer understanding of the chaperone like activity of spectrin under in-vivo like conditions we have investigated the effect of macromolecular crowders as well as phosphorylation and glycation states on chaperone activity. It is seen that the presence of non-specific, protein and non-protein macromolecular crowders do not appreciably affect chaperone function. Phosphorylation also does not affect the chaperone function unlike glycation which progressively diminishes chaperone activity. We propose a model where chaperone clients adsorb onto spectrin's surface and processes that bind to and occlude these surfaces decrease chaperone activity.

Serine protease inhibitors and human wellbeing interplay: new insights for old friends

Serine Protease Inhibitors (Serpins) control tightly regulated physiological processes and their dysfunction is associated to various diseases. Thus, increasing interest is given to these proteins as new therapeutic targets. Several studies provided functional and structural data about human serpins. By comparison, only little knowledge regarding bacterial serpins exists. Through the emergence of metagenomic studies, many bacterial serpins were identified from numerous ecological niches including the human gut microbiota. The origin, distribution and function of these proteins remain to be established. In this report, we shed light on the key role of human and bacterial serpins in health and disease. Moreover, we analyze their function, phylogeny and ecological distribution. This review highlights the potential use of bacterial serpins to set out new therapeutic approaches.

Temporal changes in myocardial collagen, matrix metalloproteinases, and their tissue inhibitors in the left ventricular myocardium in experimental chronic mitral regurgitation in rodents

Mitral regurgitation (MR) imposes left ventricular volume overload, triggering rapid ventricular dilatation, increased myocardial compliance, and, ultimately, cardiac dysfunction. Breakdown of the extracellular matrix has been hypothesized to drive these rapid changes, partially from an imbalance in the matrix metalloproteinases (MMPs) and their tissue inhibitors [tissue inhibitors of metalloproteinase (TIMPs)]. In the present study, we developed a rat model of severe MR that mimics the human condition and investigated the temporal changes in extracellular matrix-related genes, collagen biosynthesis proteins, and proteolytic enzymes over a 20-wk period. Male Sprague-Dawley rats were anesthetized to a surgical plane with mechanical ventilation, and a thoracotomy was performed to expose the apex. Using transesophageal ultrasound guidance, a needle was inserted into the beating heart to perforate the anterior mitral leaflet and create severe MR. Animals were survived for 20 wk, with some animals terminated at 2, 10, and 20 wk for analysis of left ventricular tissue. A sham group that underwent the same surgery without mitral leaflet perforation and MR were used as controls. At 2 wk post-MR, increased collagen gene expression was measured, but protein levels of collagen did not corroborate this finding. In parallel, MMP-1-to-TIMP-4, MMP-2-to-TIMP-1, and MMP-2-to-TIMP-3 ratios were significantly elevated, indicating a proteolytic milieu in the myocardium, possibly causing collagen degradation. By 20 wk, many of the initial differences seen in the proteolytic ratios were not observed, with an increase in collagen compared with the 2-wk time point. Altogether, this data indicates that an imbalance in the MMP-to-TIMP ratio may occur early and potentially contribute to the early dilatation and compliance observed structurally. NEW & NOTEWORTHY In this rodent model of severe mitral regurgitation that mimics the human condition, eccentric left ventricular dilatation occurred rapidly and persisted over the 20-wk period with parallel changes in myocardial collagen and matrix metalloproteinases that may drive the extracellular matrix breakdown.

The Manduca sexta serpinome: Analysis of serpin genes and proteins in the tobacco hornworm

Members of the serpin superfamily of proteins occur in animals, plants, bacteria, archaea and some viruses. They adopt a variety of physiological functions, including regulation of immune system, modulation of apoptosis, hormone transport and acting as storage proteins. Most members of the serpin family are inhibitors of serine proteinases. In this study, we searched the genome of Manduca sexta and identified 32 serpin genes. We analyzed the structure of these genes and the sequences of their encoded proteins. Three M. sexta genes (serpin-1, serpin-15, and serpin-28) have mutually exclusive alternatively spliced exons encoding the carboxyl-terminal reactive center loop of the protein, which is the site of interaction with target proteases. We discovered that MsSerpin-1 has 14 splicing isoforms, including two undiscovered in previous studies. Twenty-eight of the 32 M. sexta serpins include a putative secretion signal peptide and are predicted to be extracellular proteins. Phylogenetic analysis of serpins in M. sexta and Bombyx mori indicates that 17 are orthologous pairs, perhaps carrying out essential physiological functions. Analysis of the reactive center loop and hinge regions of the protein sequences indicates that 16 of the serpin genes encode proteins that may lack proteinase inhibitor activity. Our annotation and analysis of these serpin genes and their transcript profiles should lead to future advances in experimental study of their functions in insect biochemistry.

GWAS Reveal Targets in Vessel Wall Pathways to Treat Coronary Artery Disease

Coronary artery disease (CAD) is the leading cause of mortality worldwide and poses a considerable public health burden. Recent genome-wide association studies (GWAS) have revealed >100 genetic loci associated with CAD susceptibility in humans. While a number of these loci harbor gene targets of currently approved therapies, such as statins and PCSK9 inhibitors, the majority of the annotated genes at these loci encode for proteins involved in vessel wall function with no known drugs available. Importantly many of the associated genes linked to vascular (smooth muscle, endothelial, and macrophage) cell processes are now organized into distinct functional pathways, e.g., vasodilation, growth factor responses, extracellular matrix and plaque remodeling, and inflammation. In this mini-review, we highlight the most recently identified loci that have predicted roles in the vessel wall and provide genetic context for pre-existing therapies as well as new drug targets informed from GWAS. With the development of new modalities to target these pathways, (e.g., antisense oligonucleotides, CRISPR/Cas9, and RNA interference) as well as the computational frameworks to prioritize or reposition therapeutics, there is great opportunity to close the gap from initial genetic discovery to clinical translation for many patients affected by this common disease.

Serine Protease Inhibitors in Ticks: An Overview of Their Role in Tick Biology and Tick-Borne Pathogen Transmission

New tick and tick-borne pathogen control approaches that are both environmentally sustainable and which provide broad protection are urgently needed. Their development, however, will rely on a greater understanding of tick biology, tick-pathogen, and tick-host interactions. The recent advances in new generation technologies to study genomes, transcriptomes, and proteomes has resulted in a plethora of tick biomacromolecular studies. Among these, many enzyme inhibitors have been described, notably serine protease inhibitors (SPIs), whose importance in various tick biological processes is only just beginning to be fully appreciated. Among the multiple active substances secreted during tick feeding, SPIs have been shown to be directly involved in regulation of inflammation, blood clotting, wound healing, vasoconstriction and the modulation of host defense mechanisms. In light of these activities, several SPIs were examined and were experimentally confirmed to facilitate tick pathogen transmission. In addition, to prevent coagulation of the ingested blood meal within the tick alimentary canal, SPIs are also involved in blood digestion and nutrient extraction from the meal. The presence of SPIs in tick hemocytes and their involvement in tick innate immune defenses have also been demonstrated, as well as their implication in hemolymph coagulation and egg development. Considering the involvement of SPIs in multiple crucial aspects of tick-host-pathogen interactions, as well as in various aspects of the tick parasitic lifestyle, these molecules represent highly suitable and attractive targets for the development of effective tick control strategies. Here we review the current knowledge regarding this class of inhibitors in tick biology and tick-borne pathogen transmission, and their potential as targets for future tick control trials.

Characterization and expression profiling of serine protease inhibitors in the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)

BACKGROUND

Serine protease inhibitors (SPIs) have been found in all living organisms and play significant roles in digestion, development and innate immunity. In this study, we present a genome-wide identification and expression profiling of SPI genes in the diamondback moth, Plutella xylostella (L.), a major pest of cruciferous crops with global distribution and broad resistance to different types of insecticides.

RESULTS

A total of 61 potential SPI genes were identified in the P. xylostella genome, and these SPIs were classified into serpins, canonical inhibitors, and alpha-2-macroglobulins based on their modes of action. Sequence alignments showed that amino acid residues in the hinge region of known inhibitory serpins from other insect species were conserved in most P. xylostella serpins, suggesting that these P. xylostella serpins may be functionally active. Phylogenetic analysis confirmed that P. xylostella inhibitory serpins were clustered with known inhibitory serpins from six other insect species. More interestingly, nine serpins were highly similar to the orthologues in Manduca sexta which have been demonstrated to participate in regulating the prophenoloxidase activation cascade, an important innate immune response in insects. Of the 61 P.xylostella SPI genes, 33 were canonical SPIs containing seven types of inhibitor domains, including Kunitz, Kazal, TIL, amfpi, Antistasin, WAP and Pacifastin. Moreover, some SPIs contained additional non-inhibitor domains, including spondin_N, reeler, and other modules, which may be involved in protein-protein interactions. Gene expression profiling showed gene-differential, stage- and sex-specific expression patterns of SPIs, suggesting that SPIs may be involved in multiple physiological processes in P. xylostella.

CONCLUSIONS

This is the most comprehensive investigation so far on SPI genes in P. xylostella. The characterized features and expression patterns of P. xylostella SPIs indicate that the SPI family genes may be involved in innate immunity of this species. Our findings provide valuable information for uncovering further biological roles of SPI genes in P. xylostella.

Biology of Hsp47 (Serpin H1), a collagen-specific molecular chaperone

Hsp47, a collagen-specific molecular chaperone that localizes in the endoplasmic reticulum (ER), is indispensable for molecular maturation of collagen. Hsp47, which is encoded by the SERPINH1 gene, belongs to the serpin family and has the serpin fold; however, it has no serine protease inhibitory activity. Hsp47 transiently binds to procollagen in the ER, dissociates in the cis-Golgi or ER-Golgi intermediate compartment (ERGIC) in a pH-dependent manner, and is then transported back to the ER via its RDEL retention sequence. Hsp47 recognizes collagenous (Gly-Xaa-Arg) repeats on triple-helical procollagen and can prevent local unfolding and/or aggregate formation of procollagen. Gene disruption of Hsp47 in mice causes embryonic lethality due to impairments in basement membrane and collagen fibril formation. In Hsp47-knockout cells, the type I collagen triple helix forms abnormally, resulting in thin and frequently branched fibrils. Secretion of type I collagens is slow and plausible in making aggregates of procollagens in the ER of hsp47-knocked out fibroblasts, which are ultimately degraded by autophagy. Mutations in Hsp47 are causally associated with osteogenesis imperfecta. Expression of Hsp47 is strongly correlated with expression of collagens in multiple types of cells and tissues. Therefore, Hsp47 represents a promising target for treatment of collagen-related disorders, including fibrosis of the liver, lung, and other organs.

Effects of heat stress on respiratory burst, oxidative damage and SERPINH1 (HSP47) mRNA expression in rainbow trout Oncorhynchus mykiss

For rainbow trout Oncorhynchus mykiss, high temperature is a major abiotic stress that limits its growth and productivity. In this study, spleen macrophage respiratory burst (RB), serum superoxide dismutase (SOD), serum malondialdehyde (MDA) and mRNA expression of the SERPINH1 (HSP47) gene in different tissues (liver, spleen, head kidney and heart) were measured in unstressed (18 °C) and heat-stressed (25 °C) fish. Spleen macrophage RB activity, serum SOD activity and MDA content all increased significantly (P < 0.05) during heat shock, and peaked at 8, 12 and 4 h, respectively. SERPINH1 mRNA expression responded in a time- and tissue-specific manner to heat stress, which was mainly reflected in the significant up-regulation in all tissues (P < 0.05) and greater expression in the liver than the other tissues (P < 0.05). During the heat-shock recovery period, the MDA content returned to the unstressed level. These results indicate that heat shock causes cell injury, induces oxidative damage and promotes SERPINH1 mRNA expression, which plays an important protective function during heat stress in O. mykiss. In practice, close attention should be given to temperature changes in O. mykiss production to reduce the effects of high temperature.

Roles of heat shock factor 1 in isoproterenol‑induced myocardial fibrosis in mice

Although it is well known that isoproterenol (ISO) causes myocardial hypertrophy and myocardial fibrosis in rats, it has remained elusive whether heat shock factor 1 (HSF1) has a role in this process. The present study aimed to investigate the possible roles of HSF1 in ISO-induced fibrosis in mice. It was found that after administration of ISO in Kunming and HSF1-/+ mice, there was a large number of fibers deposited around blood vessels and among cardiocytes, accompanied with an obvious increase in the protein expressions of type I or III collagen and heat shock protein 47 (HSP47), as indicated by western blot analysis. After intervention with insulin-like growth factor 1 (IGF-1), myocardial fibrosis was significantly attenuated, with a paralleled decrease in the expression of collagen and HSP47 in the mice. However, in HSF1-/- mice, fiber hyperplasy was not observed after injection of ISO, and the levels of type I or III collagen and HSP47 were not significantly increased at the protein and mRNA level. Furthermore, it was demonstrated that after subcutaneous injection of ISO into the back of Kunming and HSF1-/+ mice, large amounts of HSF1 protein were localized to the nucleus, and there was an increase in phosphorylated HSF1 as indicated by western blot and immunohistochemical analysis, respectively. Intervention with IGF-1 inhibited HSF1 activation mediated by ISO. These results suggested that HSF1 is required for myocardial fibrosis in ISO-treated mice, and the underlying molecular mechanism may involve the regulation of HSP47.

How tubular epithelial cells dictate the rate of renal fibrogenesis?

The main threat to a kidney injury, whatever its cause and regardless of whether it is acute or chronic, is the initiation of a process of renal fibrogenesis, since fibrosis can auto-perpetuate and is of high prognostic significance in individual patients. In the clinic, a decrease in glomerular filtration rate correlates better with tubulointerstitial damage than with glomerular injury. Accumulation of the extracellular matrix should not be isolated from other significant cellular changes occurring in the kidney, such as infiltration by inflammatory cells, proliferation of myofibroblasts, obliteration of peritubular capillaries and atrophy of tubules. The aim of this review is to focus on tubular epithelial cells (TEC), which, necessarily involved in the repair process, eventually contribute to accelerating fibrogenesis. In the context of injury, TEC rapidly exhibit phenotypic and functional changes that recall their mesenchymal origin, and produce several growth factors known to activate myofibroblasts. Because they are high-demanding energy cells, TEC will subsequently suffer from the local hypoxia that progressively arises in a microenvironment where the matrix increases and capillaries become rarified. The combination of hypoxia and metabolic acidosis may induce a vicious cycle of sustained inflammation, at the center of which TEC dictate the rate of renal fibrogenesis.

Bayesian phylogeny analysis of vertebrate serpins illustrates evolutionary conservation of the intron and indels based six groups classification system from lampreys for ∼500 MY

The serpin superfamily is characterized by proteins that fold into a conserved tertiary structure and exploits a sophisticated and irreversible suicide-mechanism of inhibition. Vertebrate serpins are classified into six groups (V1-V6), based on three independent biological features-genomic organization, diagnostic amino acid sites and rare indels. However, this classification system was based on the limited number of mammalian genomes available. In this study, several non-mammalian genomes are used to validate this classification system using the powerful Bayesian phylogenetic method. This method supports the intron and indel based vertebrate classification and proves that serpins have been maintained from lampreys to humans for about 500 MY. Lampreys have fewer than 10 serpins, which expand into 36 serpins in humans. The two expanding groups V1 and V2 have SERPINB1/SERPINB6 and SERPINA8/SERPIND1 as the ancestral serpins, respectively. Large clusters of serpins are formed by local duplications of these serpins in tetrapod genomes. Interestingly, the ancestral HCII/SERPIND1 locus (nested within PIK4CA) possesses group V4 serpin (A2APL1, homolog of α 2-AP/SERPINF2) of lampreys; hence, pointing to the fact that group V4 might have originated from group V2. Additionally in this study, details of the phylogenetic history and genomic characteristics of vertebrate serpins are revisited.

Effects of heat stimulation and l-ascorbic acid 2-phosphate supplementation on myogenic differentiation of artificial skeletal muscle tissue constructs

Although skeletal muscle tissue engineering has been extensively studied, the physical forces produced by tissue-engineered skeletal muscles remain to be improved for potential clinical utility. In this study, we examined the effects of mild heat stimulation and supplementation of a l-ascorbic acid derivative, l-ascorbic acid 2-phosphate (AscP), on myoblast differentiation and physical force generation of tissue-engineered skeletal muscles. Compared with control cultures at 37°C, mouse C2C12 myoblast cells cultured at 39°C enhanced myotube diameter (skeletal muscle hypertrophy), whereas mild heat stimulation did not promote myotube formation (differentiation rate). Conversely, AscP supplementation resulted in an increased differentiation rate but did not induce skeletal muscle hypertrophy. Following combined treatment with mild heat stimulation and AscP supplementation, both skeletal muscle hypertrophy and differentiation rate were enhanced. Moreover, the active tension produced by the tissue-engineered skeletal muscles was improved following combined treatment. These findings indicate that tissue culture using mild heat stimulation and AscP supplementation is a promising approach to enhance the function of tissue-engineered skeletal muscles. Copyright © 2015 John Wiley & Sons, Ltd.

Molecular Consequences of the SERPINH1/HSP47 Mutation in the Dachshund Natural Model of Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a heritable connective tissue disease characterized by bone fragility and increased risk of fractures. Up to now, mutations in at least 18 genes have been associated with dominant and recessive forms of OI that affect the production or post-translational processing of procollagen or alter bone homeostasis. Among those, SERPINH1 encoding heat shock protein 47 (HSP47), a chaperone exclusive for collagen folding in the ER, was identified to cause a severe form of OI in dachshunds (L326P) as well as in humans (one single case with a L78P mutation). To elucidate the disease mechanism underlying OI in the dog model, we applied a range of biochemical assays to mutant and control skin fibroblasts as well as on bone samples. These experiments revealed that type I collagen synthesized by mutant cells had decreased electrophoretic mobility. Procollagen was retained intracellularly with concomitant dilation of ER cisternae and activation of the ER stress response markers GRP78 and phospho-eIF2α, thus suggesting a defect in procollagen processing. In line with the migration shift detected on SDS-PAGE of cell culture collagen, extracts of bone collagen from the OI dog showed a similar mobility shift, and on tandem mass spectrometry, the chains were post-translationally overmodified. The bone collagen had a higher content of pyridinoline than control dog bone. We conclude that the SERPINH1 mutation in this naturally occurring model of OI impairs how HSP47 acts as a chaperone in the ER. This results in abnormal post-translational modification and cross-linking of the bone collagen.

Transcriptional Response to Acute Thermal Exposure in Juvenile Chinook Salmon Determined by RNAseq

Thermal exposure is a serious and growing challenge facing fish species worldwide. Chinook salmon (Oncorhynchus tshawytscha) living in the southern portion of their native range are particularly likely to encounter warmer water due to a confluence of factors. River alterations have increased the likelihood that juveniles will be exposed to warm water temperatures during their freshwater life stage, which can negatively impact survival, growth, and development and pose a threat to dwindling salmon populations. To better understand how acute thermal exposure affects the biology of salmon, we performed a transcriptional analysis of gill tissue from Chinook salmon juveniles reared at 12° and exposed acutely to water temperatures ranging from ideal to potentially lethal (12° to 25°). Reverse-transcribed RNA libraries were sequenced on the Illumina HiSeq2000 platform and a de novo reference transcriptome was created. Differentially expressed transcripts were annotated using Blast2GO and relevant gene clusters were identified. In addition to a high degree of downregulation of a wide range of genes, we found upregulation of genes involved in protein folding/rescue, protein degradation, cell death, oxidative stress, metabolism, inflammation/immunity, transcription/translation, ion transport, cell cycle/growth, cell signaling, cellular trafficking, and structure/cytoskeleton. These results demonstrate the complex multi-modal cellular response to thermal stress in juvenile salmon.

Chaperone Hsp47 Drives Malignant Growth and Invasion by Modulating an ECM Gene Network

The extracellular matrix (ECM) is a determining factor in the tumor microenvironment that restrains or promotes malignant growth. In this report, we show how the molecular chaperone protein Hsp47 functions as a nodal hub in regulating an ECM gene transcription network. A transcription network analysis showed that Hsp47 expression was activated during breast cancer development and progression. Hsp47 silencing reprogrammed human breast cancer cells to form growth-arrested and/or noninvasive structures in 3D cultures, and to limit tumor growth in xenograft assays by reducing deposition of collagen and fibronectin. Coexpression network analysis also showed that levels of microRNA(miR)-29b and -29c were inversely correlated with expression of Hsp47 and ECM network genes in human breast cancer tissues. We found that miR-29 repressed expression of Hsp47 along with multiple ECM network genes. Ectopic expression of miR-29b suppressed malignant phenotypes of breast cancer cells in 3D culture. Clinically, increased expression of Hsp47 and reduced levels of miR-29b and -29c were associated with poor survival outcomes in breast cancer patients. Our results show that Hsp47 is regulated by miR-29 during breast cancer development and progression, and that increased Hsp47 expression promotes cancer progression in part by enhancing deposition of ECM proteins.

Deletion of the collagen-specific molecular chaperone Hsp47 causes endoplasmic reticulum stress-mediated apoptosis of hepatic stellate cells

Chronic liver injury, often caused by alcoholism and viral hepatitis, causes liver fibrosis via the induction of collagen production. In liver fibrosis, hepatic stellate cells (HSCs) are activated and transform into myofibroblasts, which actively produce and secrete collagen into the extracellular matrix. Hsp47 (heat shock protein 47) is a collagen-specific molecular chaperone that is essential for the maturation and secretion of collagen. Here, we used the Cre-LoxP system to disrupt the Hsp47 gene in isolated HSCs from Hsp47 floxed mice. Immature type I procollagen accumulated and partially aggregated in Hsp47-KO HSCs. This accumulation was augmented when autophagy was inhibited, which induced expression of the endoplasmic reticulum (ER) stress-inducible proteins BiP (immunoglobulin heavy chain-binding protein) and Grp94 (94-kDa glucose-regulated protein). The inhibition of autophagy in Hsp47-KO HSCs also induced CHOP (CCAAT/enhancer-binding protein homologous protein), which is an ER stress-induced transcription factor responsible for apoptosis. These data suggest that apoptosis is induced through ER stress by procollagen accumulation in Hsp47-KO HSCs when autophagy is inhibited. Thus, Hsp47 could be a promising therapeutic target in liver fibrosis.

HSP47 and FKBP65 cooperate in the synthesis of type I procollagen

Osteogenesis imperfecta (OI) is a genetic disorder that results in low bone mineral density and brittle bones. Most cases result from dominant mutations in the type I procollagen genes, but mutations in a growing number of genes have been identified that produce autosomal recessive forms of the disease. Among these include mutations in the genes SERPINH1 and FKBP10, which encode the type I procollagen chaperones HSP47 and FKBP65, respectively, and predominantly produce a moderately severe form of OI. Little is known about the biochemical consequences of the mutations and how they produce OI. We have identified a new OI mutation in SERPINH1 that results in destabilization and mislocalization of HSP47 and secondarily has similar effects on FKBP65. We found evidence that HSP47 and FKBP65 act cooperatively during posttranslational maturation of type I procollagen and that FKBP65 and HSP47 but fail to properly interact in mutant HSP47 cells. These results thus reveal a common cellular pathway in cases of OI caused by HSP47 and FKBP65 deficiency.

Role of LARP6 and nonmuscle myosin in partitioning of collagen mRNAs to the ER membrane

Type I collagen is extracellular matrix protein composed of two α1(I) and one α2(I) polypeptides that fold into triple helix. Collagen polypeptides are translated in coordination to synchronize the rate of triple helix folding to the rate of posttranslational modifications of individual polypeptides. This is especially important in conditions of high collagen production, like fibrosis. It has been assumed that collagen mRNAs are targeted to the membrane of the endoplasmic reticulum (ER) after translation of the signal peptide and by signal peptide recognition particle (SRP). Here we show that collagen mRNAs associate with the ER membrane even when translation is inhibited. Knock down of LARP6, an RNA binding protein which binds 5' stem-loop of collagen mRNAs, releases a small amount of collagen mRNAs from the membrane. Depolimerization of nonmuscle myosin filaments has a similar, but stronger effect. In the absence of LARP6 or nonmuscle myosin filaments collagen polypeptides become hypermodified, are poorly secreted and accumulate in the cytosol. This indicates lack of coordination of their synthesis and retro-translocation due to hypermodifications and misfolding. Depolimerization of nonmuscle myosin does not alter the secretory pathway through ER and Golgi, suggesting that the role of nonmuscle myosin is primarily to partition collagen mRNAs to the ER membrane. We postulate that collagen mRNAs directly partition to the ER membrane prior to synthesis of the signal peptide and that LARP6 and nonmuscle myosin filaments mediate this process. This allows coordinated initiation of translation on the membrane bound collagen α1(I) and α2(I) mRNAs, a necessary step for proper synthesis of type I collagen.

MiR-29b inhibits collagen maturation in hepatic stellate cells through down-regulating the expression of HSP47 and lysyl oxidase

Altered expression of miR-29b is implicated in the pathogenesis and progression of liver fibrosis. We and others previously demonstrated that miR-29b down-regulates the expression of several extracellular-matrix (ECM) genes including Col 1A1, Col 3A1 and Elastin via directly targeting their 3'-UTRs. However, whether or not miR-29b plays a role in the post-translational regulation of ECM biosynthesis has not been reported. Heat shock protein 47 (HSP47) and lysyl oxidase (LOX) are known to be essential for ECM maturation. In this study we have demonstrated that expression of HSP47 and LOX was significantly up-regulated in culture-activated primary rat hepatic stellate cells (HSCs), TGF-β stimulated LX-2 cells and liver tissue of CCl4-treated mice, which was accompanied by a decrease of miR-29b level. In addition, over-expression of miR-29b in LX-2 cells resulted in significant inhibition on HSP47 and LOX expression. Mechanistically, miR-29b inhibited the expression of a reporter gene that contains the respective full-length 3'-UTR from HSP47 and LOX gene, and this inhibitory effect was abolished by the deletion of a putative miR-29b targeting sequence from the 3'-UTRs. Transfection of LX-2 cells with miR-29b led to abnormal collagen structure as shown by electron-microscopy, presumably through down-regulation of the expression of molecules involved in ECM maturation including HSP47 and LOX. These results demonstrated that miR-29b is involved in regulating the post-translational processing of ECM and fibril formation.

Bleomycin delivery by osmotic minipump: similarity to human scleroderma interstitial lung disease

The interstitial lung diseases (ILD) include a large number of chronic, progressive, irreversible respiratory disorders involving pulmonary fibrosis, the most common of which are idiopathic pulmonary fibrosis and scleroderma lung disease (SSc ILD). Because bleomycin causes lung fibrosis when used in cancer chemotherapy, it is used to model human ILD in rodents. In most studies, bleomycin has been delivered directly into the lung by intratracheal or intraoral administration. Here we have compared the effects in mice of bleomycin delivered directly into the lungs (direct model) or systemically using osmotic minipumps (pump model) to determine which more closely resembles human ILD. The pump model is more similar to human SSc ILD in that: 1) lung injury/fibrosis is limited to the subpleural portion of the lung in the pump model and in SSc ILD, whereas the entire lung is affected in the direct model; 2) conversely, there is massive inflammation throughout the lung in the direct model, whereas inflammation is limited in the pump model and in SSc ILD; 3) hypertrophic type II alveolar epithelial cells are present at high levels in SSc ILD and in the pump model but not in the direct model; and 4) lung fibrosis is accompanied by dermal fibrosis. The pump model is also move convenient and humane than the direct model because there is less weight loss and mortality.

Serum heat shock protein 47 levels are elevated in acute exacerbation of idiopathic pulmonary fibrosis

Little is known about the pathophysiology of acute exacerbation (AE) of idiopathic pulmonary fibrosis (IPF). Heat shock protein 47 (HSP47), a collagen-specific molecular chaperone, is essential for biosynthesis and secretion of collagen molecules. Previous studies in experimental animal fibrosis models have shown that downregulation of HSP47 expression reduces collagen production and diminishes fibrosis progression. In this study, serum HSP47 levels were evaluated to elucidate pathogenic differences involving HSP47 between AE-IPF and stable (S)-IPF. Subjects comprised 20 AE-IPF and 33 S-IPF patients. Serum levels of HSP47, Krebs von den Lungen-6 (KL-6), surfactant protein (SP)-A, SP-D, and lactate dehydrogenase (LDH) were measured. Immunohistochemical analysis of lung HSP47 expression was determined in biopsy and autopsy tissues diagnosed as diffuse alveolar damage (DAD) and usual interstitial pneumonia (UIP). Serum levels of HSP47 were significantly higher in AE-IPF than in S-IPF patients, whereas serum levels of KL-6, SP-A, and SP-D did not differ significantly. Receiver operating characteristic curves revealed that HSP47 was superior for discriminating AE-IPF and S-IPF. The cutoff for HSP47 resulting in the highest diagnostic accuracy was 559.4 pg/mL; sensitivity, specificity, and diagnostic accuracy were 100.0%, 93.9%, and 96.2%, respectively. Immunohistochemical analysis revealed that pulmonary HSP47 expression was greater in DAD than UIP tissues. Serum HSP47 was significantly higher in AE-IPF than in S-IPF patients, suggesting that underlying fibrogenic mechanisms involving HSP47 differ in the two conditions.