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1.
Microsurgery ; 44(4): e31186, 2024 May.
Article in English | MEDLINE | ID: mdl-38716649

ABSTRACT

INTRODUCTION: Free flap transfer for head and neck defects has gained worldwide acceptance. Because flap failure is a devastating outcome, studies have attempted to identify risk factors-including renal failure. We sought to determine whether end-stage renal disease (ESRD) patients undergoing dialysis are at increased risk of flap failure following microsurgical head and neck reconstruction. PATIENTS AND METHODS: The study's participants were patients who underwent free flap reconstruction in the head and neck region at Hualien Tzu Chi Hospital between January 2010 and December 2019. We used the National Health Insurance "Specific Diagnosis and Treatment Code" to identify patients undergoing dialysis; these patients comprised the dialysis group, whose members were matched to a non-dialysis group for age and gender. The dependent variables were flap survival rate, take-back rate, and flap failure risk between the dialysis and non-dialysis groups. RESULTS: We included 154 patients in the dialysis (n = 14) and non-dialysis (n = 140) groups. The groups were similar in terms of age and most comorbidities, except diabetes mellitus, hypertension, and coronary artery disease, which were more prevalent in the dialysis group. The dialysis and non-dialysis groups had similar flap survival rates (100% vs. 92.9%; p = .600). Twenty-three patients underwent take-back surgery, most in the non-dialysis group (14.3% vs. 15.0%; p = 1.000). Patients in the dialysis group were more likely to have prolonged intensive care unit stays; however, dialysis alone did not predict flap failure (OR: 0.83; p = .864). CONCLUSION: This study found no significant differences in free flap survival and take-back rates between patients with and without dialysis. Dialysis did not increase the risk of flap failure following microsurgical head and neck reconstruction in this study; however, prospective, randomized controlled trials are needed.


Subject(s)
Free Tissue Flaps , Head and Neck Neoplasms , Kidney Failure, Chronic , Microsurgery , Plastic Surgery Procedures , Renal Dialysis , Humans , Male , Female , Kidney Failure, Chronic/therapy , Kidney Failure, Chronic/complications , Middle Aged , Free Tissue Flaps/transplantation , Plastic Surgery Procedures/methods , Microsurgery/methods , Head and Neck Neoplasms/surgery , Head and Neck Neoplasms/complications , Aged , Retrospective Studies , Graft Survival , Risk Factors , Adult
2.
Plast Reconstr Surg Glob Open ; 12(3): e5654, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38510332

ABSTRACT

Reconstruction of the plantar forefoot area is challenging because it performs important functions, including carrying the body weight and balancing the ambulation gait, and lacks similar skin and soft tissues to manage the adjacent region. Herein, we shared our experience of using a lateral toe pulp flap and reviewed the relevant literature on this topic. A 33-year-old man presented with a large granuloma in the left plantar forefoot area after undergoing multiple operations owing to the diagnosis of callus. After tumor excision, the wound exhibited tendon exposure and a large infected dead space in the myofascial layer. After serial debridement with negative pressure wound therapy, the wound, which measured ~3.5 × 2.5 cm2, was reconstructed using a lateral toe pulp flap. The flap was transposed to obliterate the dead space; the remaining skin defect (size: ~2 × 2 cm2) was resurfaced with a full-thickness skin graft, harvested from the left inguinal region, followed by primary closure of the flap donor site. The flap completely survived. The lateral toe pulp flap is an easy, effective, and reliable option for reconstruction of the defects in the plantar forefoot area.

3.
Medicine (Baltimore) ; 102(7): e33013, 2023 Feb 17.
Article in English | MEDLINE | ID: mdl-36800613

ABSTRACT

RATIONALE: The use of ChAdOx1 nCoV-19 (Astra Zeneca) vaccine has proven beneficial, but in a limited number of the general population, it was found to be associated with vaccine-induced immune thrombotic thrombocytopenia (VITT). However, there have been no reports of this complication occurring in a microsurgical free tissue transfer. PATIENT CONCERNS: A 49-year-old man developed an acute myocardial infarction 3 weeks after receiving his first dose of ChAdOx1 nCoV-19 in June 2021. Three months later, he presented with right third toe wet gangrene with extension into the plantar foot nine days after receiving his second dose of ChAdOx1 nCoV-19 vaccine. DIAGNOSIS: Based on recent exposure to vaccination, the timing of inoculation before the development of his symptoms, and serology tests (platelet, D-dimer, and anti-PF4 antibodies), the patient was diagnosed with VITT. INTERVENTIONS: Fasciectomy and sequestrectomy were performed for wound bed preparation. Limb salvage was done using free vastus lateralis muscle flap and skin graft for reconstruction. OUTCOME: The flap was complicated by persistent microthrombi leading to superficial necrosis without vascular pedicle compromise. Repeated debridement of the superficial necrosis was done. Three months after the development of VITT, no further new superficial necrosis was seen. A well-contoured flap was seen 5 months after the initial surgery. LESSONS: We believe this is the first case describing microthrombi in the free flap due to VITT after microsurgical reconstruction. Patients and surgeons should be advised of this possible risk when contemplating microsurgery once VITT has developed after ChAdOx1 nCoV-19 administration.


Subject(s)
ChAdOx1 nCoV-19 , Free Tissue Flaps , Purpura, Thrombocytopenic, Idiopathic , Thrombosis , Humans , Male , Middle Aged , ChAdOx1 nCoV-19/adverse effects , Purpura, Thrombocytopenic, Idiopathic/chemically induced , Thrombosis/chemically induced , COVID-19/prevention & control
4.
J Biomed Sci ; 29(1): 63, 2022 Sep 02.
Article in English | MEDLINE | ID: mdl-36050716

ABSTRACT

Fibrosis-related disorders account for an enormous burden of disease-associated morbidity and mortality worldwide. Fibrosis is defined by excessive extracellular matrix deposition at fibrotic foci in the organ tissue following injury, resulting in abnormal architecture, impaired function and ultimately, organ failure. To date, there lacks effective pharmacological therapy to target fibrosis per se, highlighting the urgent need to identify novel drug targets against organ fibrosis. Recently, we have discovered the critical role of a fibroblasts-enriched endoplasmic reticulum protein disulfide isomerase (PDI), thioredoxin domain containing 5 (TXNDC5), in cardiac, pulmonary, renal and liver fibrosis, showing TXNDC5 is required for the activation of fibrogenic transforming growth factor-ß signaling cascades depending on its catalytic activity as a PDI. Moreover, deletion of TXNDC5 in fibroblasts ameliorates organ fibrosis and preserves organ function by inhibiting myofibroblasts activation, proliferation and extracellular matrix production. In this review, we detailed the molecular and cellular mechanisms by which TXNDC5 promotes fibrogenesis in various tissue types and summarized potential therapeutic strategies targeting TXNDC5 to treat organ fibrosis.


Subject(s)
Protein Disulfide-Isomerases , Thioredoxins , Fibroblasts/metabolism , Fibrosis , Humans , Myofibroblasts , Protein Disulfide-Isomerases/genetics , Protein Disulfide-Isomerases/metabolism , Thioredoxins/genetics , Thioredoxins/metabolism
5.
J Mol Diagn ; 24(11): 1195-1206, 2022 11.
Article in English | MEDLINE | ID: mdl-35963521

ABSTRACT

Identification of specific leukemia subtypes is a key to successful risk-directed therapy in childhood acute lymphoblastic leukemia (ALL). Although RNA sequencing (RNA-seq) is the best approach to identify virtually all specific leukemia subtypes, the routine use of this method is too costly for patients in resource-limited countries. This study enrolled 295 patients with pediatric ALL from 2010 to 2020. Routine screening could identify major cytogenetic alterations in approximately 69% of B-cell ALL (B-ALL) cases by RT-PCR, DNA index, and multiplex ligation-dependent probe amplification. STIL-TAL1 was present in 33% of T-cell ALL (T-ALL) cases. The remaining samples were submitted for RNA-seq. More than 96% of B-ALL cases and 74% of T-ALL cases could be identified based on the current molecular classification using this sequential approach. Patients with Philadelphia chromosome-like ALL constituted only 2.4% of the entire cohort, a rate even lower than those with ZNF384-rearranged (4.8%), DUX4-rearranged (6%), and Philadelphia chromosome-positive (4.4%) ALL. Patients with ETV6-RUNX1, high hyperdiploidy, PAX5 alteration, and DUX4 rearrangement had favorable prognosis, whereas those with hypodiploid and KMT2A and MEF2D rearrangement ALL had unfavorable outcomes. With the use of multiplex ligation-dependent probe amplification, DNA index, and RT-PCR in B-ALL and RT-PCR in T-ALL followed by RNA-seq, childhood ALL can be better classified to improve clinical assessments.


Subject(s)
Precursor Cell Lymphoblastic Leukemia-Lymphoma , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma , Child , Humans , Oncogene Proteins, Fusion/genetics , Philadelphia Chromosome , Precursor Cell Lymphoblastic Leukemia-Lymphoma/diagnosis , Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics , Aneuploidy , DNA
6.
Molecules ; 27(5)2022 Feb 25.
Article in English | MEDLINE | ID: mdl-35268651

ABSTRACT

Gold has always been regarded as a symbol of nobility, and its shiny golden appearance has always attracted the attention of many people. Gold has good ductility, molecular recognition properties, and good biocompatibility. At present, gold is being used in many fields. When gold particles are as small as several nanometers, their physical and chemical properties vary with their size in nanometers. The surface area of a nano-sized gold surface has a special effect. Therefore, gold nanoparticles can, directly and indirectly, give rise to different biological activities. For example, if the surface of the gold is sulfided. Various substances have a strong chemical reactivity and are easy to combine with sulfhydryl groups; hence, nanogold is often used in biomedical testing, disease diagnosis, and gene detection. Nanogold is easy to bind to proteins, such as antibodies, enzymes, or cytokines. In fact, scientists use nanogold to bind special antibodies, as a tool for targeting cancer cells. Gold nanoparticles are also directly cytotoxic to cancer cells. For diseases caused by inflammation and oxidative damage, gold nanoparticles also have antioxidant and anti-inflammatory effects. Based on these unique properties, gold nanoparticles have become the most widely studied metal nanomaterials. Many recent studies have further demonstrated that gold nanoparticles are beneficial for humans, due to their functional pharmacological properties in a variety of diseases. The content of this review will be the application of gold nanoparticles in treating or diagnosing pressing diseases, such as cancers, retinopathy, neurological diseases, skin disorders, bowel diseases, bone cartilage disorders, cardiovascular diseases, infections, and metabolic syndrome. Gold nanoparticles have shown very obvious therapeutic and application potential.


Subject(s)
Gold
7.
Gut ; 71(9): 1876-1891, 2022 09.
Article in English | MEDLINE | ID: mdl-34933915

ABSTRACT

BACKGROUND AND OBJECTIVES: Liver fibrosis (LF) occurs following chronic liver injuries. Currently, there is no effective therapy for LF. Recently, we identified thioredoxin domain containing 5 (TXNDC5), an ER protein disulfide isomerase (PDI), as a critical mediator of cardiac and lung fibrosis. We aimed to determine if TXNDC5 also contributes to LF and its potential as a therapeutic target for LF. DESIGN: Histological and transcriptome analyses on human cirrhotic livers were performed. Col1a1-GFPTg , Alb-Cre;Rosa26-tdTomato and Tie2-Cre/ERT2;Rosa26-tdTomato mice were used to determine the cell type(s) where TXNDC5 was induced following liver injury. In vitro investigations were conducted in human hepatic stellate cells (HSCs). Col1a2-Cre/ERT2;Txndc5fl/fl (Txndc5cKO ) and Alb-Cre;Txndc5fl/fl (Txndc5Hep-cKO ) mice were generated to delete TXNDC5 in HSCs and hepatocytes, respectively. Carbon tetrachloride treatment and bile duct ligation surgery were employed to induce liver injury/fibrosis in mice. The extent of LF was quantified using histological, imaging and biochemical analyses. RESULTS: TXNDC5 was upregulated markedly in human and mouse fibrotic livers, particularly in activated HSC at the fibrotic foci. TXNDC5 was induced by transforming growth factor ß1 (TGFß1) in HSCs and it was both required and sufficient for the activation, proliferation, survival and extracellular matrix production of HSC. Mechanistically, TGFß1 induces TXNDC5 expression through increased ER stress and ATF6-mediated transcriptional regulation. In addition, TXNDC5 promotes LF by redox-dependent JNK and signal transducer and activator of transcription 3 activation in HSCs through its PDI activity, activating HSCs and making them resistant to apoptosis. HSC-specific deletion of Txndc5 reverted established LF in mice. CONCLUSIONS: ER protein TXNDC5 promotes LF through redox-dependent HSC activation, proliferation and excessive extracellular matrix production. Targeting TXNDC5, therefore, could be a potential novel therapeutic strategy to ameliorate LF.


Subject(s)
Hepatic Stellate Cells , Liver Cirrhosis , Animals , Carbon Tetrachloride/adverse effects , Carbon Tetrachloride/metabolism , Fibrosis , Hepatic Stellate Cells/metabolism , Hepatocytes/metabolism , Humans , Liver/metabolism , Liver Cirrhosis/pathology , Mice , Protein Disulfide-Isomerases/adverse effects , Protein Disulfide-Isomerases/genetics , Protein Disulfide-Isomerases/metabolism , Thioredoxins/genetics , Thioredoxins/metabolism
8.
J Clin Invest ; 131(5)2021 03 01.
Article in English | MEDLINE | ID: mdl-33465051

ABSTRACT

Renal fibrosis, a common pathological manifestation of virtually all types of chronic kidney disease (CKD), often results in diffuse kidney scarring and predisposes to end-stage renal disease. Currently, there is no effective therapy against renal fibrosis. Recently, our laboratory identified an ER-resident protein, thioredoxin domain containing 5 (TXNDC5), as a critical mediator of cardiac fibrosis. Transcriptome analyses of renal biopsy specimens from patients with CKD revealed marked TXNDC5 upregulation in fibrotic kidneys, suggesting a potential role of TXNDC5 in renal fibrosis. Employing multiple fluorescence reporter mouse lines, we showed that TXNDC5 was specifically upregulated in collagen-secreting fibroblasts in fibrotic mouse kidneys. In addition, we showed that TXNDC5 was required for TGF-ß1-induced fibrogenic responses in human kidney fibroblasts (HKFs), whereas TXNDC5 overexpression was sufficient to promote HKF activation, proliferation, and collagen production. Mechanistically, we showed that TXNDC5, transcriptionally controlled by the ATF6-dependent ER stress pathway, mediated its profibrogenic effects by enforcing TGF-ß signaling activity through posttranslational stabilization and upregulation of type I TGF-ß receptor in kidney fibroblasts. Using a tamoxifen-inducible, fibroblast-specific Txndc5 knockout mouse line, we demonstrated that deletion of Txndc5 in kidney fibroblasts mitigated the progression of established kidney fibrosis, suggesting the therapeutic potential of TXNDC5 targeting for renal fibrosis and CKD.


Subject(s)
Fibroblasts/metabolism , Kidney Diseases/metabolism , Kidney/metabolism , Signal Transduction , Thioredoxins/biosynthesis , Transforming Growth Factor beta1/metabolism , Activating Transcription Factor 6/genetics , Activating Transcription Factor 6/metabolism , Animals , Cell Line , Endoplasmic Reticulum Stress/genetics , Fibroblasts/pathology , Fibrosis , Kidney/pathology , Kidney Diseases/genetics , Kidney Diseases/pathology , Mice , Mice, Knockout , Thioredoxins/genetics , Transforming Growth Factor beta1/genetics , Up-Regulation
9.
Nat Commun ; 11(1): 4254, 2020 08 26.
Article in English | MEDLINE | ID: mdl-32848143

ABSTRACT

Pulmonary fibrosis (PF) is a major public health problem with limited therapeutic options. There is a clear need to identify novel mediators of PF to develop effective therapeutics. Here we show that an ER protein disulfide isomerase, thioredoxin domain containing 5 (TXNDC5), is highly upregulated in the lung tissues from both patients with idiopathic pulmonary fibrosis and a mouse model of bleomycin (BLM)-induced PF. Global deletion of Txndc5 markedly reduces the extent of PF and preserves lung function in mice following BLM treatment. Mechanistic investigations demonstrate that TXNDC5 promotes fibrogenesis by enhancing TGFß1 signaling through direct binding with and stabilization of TGFBR1 in lung fibroblasts. Moreover, TGFß1 stimulation is shown to upregulate TXNDC5 via ER stress/ATF6-dependent transcriptional control in lung fibroblasts. Inducing fibroblast-specific deletion of Txndc5 mitigates the progression of BLM-induced PF and lung function deterioration. Targeting TXNDC5, therefore, could be a novel therapeutic approach against PF.


Subject(s)
Idiopathic Pulmonary Fibrosis/etiology , Idiopathic Pulmonary Fibrosis/metabolism , Protein Disulfide-Isomerases/metabolism , Pulmonary Fibrosis/etiology , Pulmonary Fibrosis/metabolism , Receptor, Transforming Growth Factor-beta Type I/metabolism , Thioredoxins/metabolism , Transforming Growth Factor beta1/metabolism , Animals , Bleomycin/toxicity , Disease Models, Animal , Endoplasmic Reticulum Stress , Gene Deletion , Humans , Idiopathic Pulmonary Fibrosis/pathology , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Protein Disulfide-Isomerases/genetics , Protein Folding , Protein Stability , Pulmonary Fibrosis/pathology , Receptor, Transforming Growth Factor-beta Type I/chemistry , Signal Transduction , Thioredoxins/antagonists & inhibitors , Thioredoxins/genetics , Up-Regulation
10.
Cell ; 182(1): 226-244.e17, 2020 07 09.
Article in English | MEDLINE | ID: mdl-32649875

ABSTRACT

Lung cancer in East Asia is characterized by a high percentage of never-smokers, early onset and predominant EGFR mutations. To illuminate the molecular phenotype of this demographically distinct disease, we performed a deep comprehensive proteogenomic study on a prospectively collected cohort in Taiwan, representing early stage, predominantly female, non-smoking lung adenocarcinoma. Integrated genomic, proteomic, and phosphoproteomic analysis delineated the demographically distinct molecular attributes and hallmarks of tumor progression. Mutational signature analysis revealed age- and gender-related mutagenesis mechanisms, characterized by high prevalence of APOBEC mutational signature in younger females and over-representation of environmental carcinogen-like mutational signatures in older females. A proteomics-informed classification distinguished the clinical characteristics of early stage patients with EGFR mutations. Furthermore, integrated protein network analysis revealed the cellular remodeling underpinning clinical trajectories and nominated candidate biomarkers for patient stratification and therapeutic intervention. This multi-omic molecular architecture may help develop strategies for management of early stage never-smoker lung adenocarcinoma.


Subject(s)
Disease Progression , Lung Neoplasms/genetics , Lung Neoplasms/pathology , Proteogenomics , Smoking/genetics , Adenocarcinoma of Lung/genetics , Adenocarcinoma of Lung/pathology , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Carcinogens/toxicity , Cohort Studies , Cytosine Deaminase/metabolism , Asia, Eastern , Gene Expression Regulation, Neoplastic , Gene Regulatory Networks , Genome, Human , Humans , Matrix Metalloproteinases/metabolism , Mutation/genetics , Principal Component Analysis
11.
Aging (Albany NY) ; 11(3): 986-1007, 2019 02 13.
Article in English | MEDLINE | ID: mdl-30760647

ABSTRACT

Spinocerebellar ataxia (SCA) type 17 is an autosomal dominant ataxia caused by expanded polyglutamine (polyQ) tract in the TATA-box binding protein (TBP). Substantial studies have shown involvement of compromised mitochondria biogenesis regulator peroxisome proliferator-activated receptor gamma-coactivator 1 alpha (PGC-1α), nuclear factor erythroid 2-related factor 2 (NRF2), nuclear factor-Y subunit A (NFYA), and their downstream target genes in the pathogenesis of polyQ-expansion diseases. The extracts of Paeonia lactiflora (P. lactiflora) and Glycyrrhiza uralensis (G. uralensis) have long been used as a Chinese herbal medicine (CHM). Shaoyao Gancao Tang (SG-Tang) is a formulated CHM made of P. lactiflora and G. uralensis at a 1:1 ratio. In the present study, we demonstrated the aggregate-inhibitory and anti-oxidative effect of SG-Tang in 293 TBP/Q79 cells. We then showed that SG-Tang reduced the aggregates and ameliorated the neurite outgrowth deficits in TBP/Q79 SH-SY5Y cells. SG-Tang upregulated expression levels of NFYA, PGC-1α, NRF2, and their downstream target genes in TBP/Q79 SH-SY5Y cells. Knock down of NFYA, PGC-1α, and NRF2 attenuated the neurite outgrowth promoting effect of SG-Tang on TBP/Q79 SH-SY5Y cells. Furthermore, SG-Tang inhibited aggregation and rescued motor-deficits in SCA17 mouse model. The study results suggest the potential of SG-Tang in treating SCA17 and probable other polyQ diseases.


Subject(s)
Drugs, Chinese Herbal/pharmacology , Drugs, Chinese Herbal/therapeutic use , Spinocerebellar Ataxias/drug therapy , Animals , CCAAT-Binding Factor/genetics , CCAAT-Binding Factor/metabolism , Cell Line , Drug Evaluation, Preclinical , Gene Knockdown Techniques , Glycyrrhiza uralensis , Humans , Mice, Transgenic , Molecular Targeted Therapy , NF-E2-Related Factor 2/genetics , NF-E2-Related Factor 2/metabolism , Neuronal Outgrowth/drug effects , Oxidative Stress/drug effects , Paeonia , Peptides/metabolism , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha/genetics , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha/metabolism , Phytotherapy , Spinocerebellar Ataxias/metabolism , TATA-Box Binding Protein/drug effects , TATA-Box Binding Protein/metabolism
12.
Neurotoxicology ; 67: 259-269, 2018 07.
Article in English | MEDLINE | ID: mdl-29936316

ABSTRACT

Spinocerebellar ataxia type 17 (SCA17) is caused by the expansion of translated CAG repeat in the TATA box binding protein (TBP) gene encoding a long polyglutamine (polyQ) tract in the TBP protein, which leads to intracellular accumulation of aggregated TBP and cell death. The molecular chaperones act in preventing protein aggregation to ameliorate downstream harmful events. In this study, we used Tet-On cells with inducible SCA17 TBP/Q79-GFP expression to test five in-house NC009 indole compounds for neuroprotection. We found that both aggregation and polyQ-induced reactive oxygen species can be significantly prohibited by the tested NC009 compounds in Tet-On TBP/Q79 293 cells. Among the five indole compounds, NC009-1 up-regulated expression of heat shock protein family B (small) member 1 (HSPB1) chaperone to reduce polyQ aggregation and promote neurite outgrowth in neuronal differentiated TBP/Q79 SH-SY5Y cells. The increased HSPB1 thus ameliorated the increased BH3 interacting domain death agonist (BID), cytochrome c (CYCS) release, and caspase 3 (CASP3) activation which result in apoptosis. Knock down of HSPB1 attenuated the effects of NC009-1 on TBP/Q79 SH-SY5Y cells, suggesting that HSPB1 might be one of the major pathways involved for NC009-1 effects. NC009-1 further reduced polyQ aggregation in Purkinje cells and ameliorated behavioral deficits in SCA17 TBP/Q109 transgenic mice. Our results suggest that NC009-1 has a neuroprotective effect on SCA17 cell and mouse models to support its therapeutic potential in SCA17 treatment.


Subject(s)
Heat-Shock Proteins/metabolism , Indoles/therapeutic use , Mental Disorders/drug therapy , Mental Disorders/metabolism , Neoplasm Proteins/metabolism , Neuronal Outgrowth/drug effects , TATA-Box Binding Protein/metabolism , Animals , Cell Line, Tumor , Dose-Response Relationship, Drug , Heat-Shock Proteins/agonists , Humans , Indoles/chemistry , Indoles/pharmacology , Mice , Mice, Transgenic , Molecular Chaperones , Neoplasm Proteins/agonists , Neuronal Outgrowth/physiology , TATA-Box Binding Protein/genetics
13.
Circ Res ; 122(8): 1052-1068, 2018 04 13.
Article in English | MEDLINE | ID: mdl-29535165

ABSTRACT

RATIONALE: Cardiac fibrosis plays a critical role in the pathogenesis of heart failure. Excessive accumulation of extracellular matrix (ECM) resulting from cardiac fibrosis impairs cardiac contractile function and increases arrhythmogenicity. Current treatment options for cardiac fibrosis, however, are limited, and there is a clear need to identify novel mediators of cardiac fibrosis to facilitate the development of better therapeutics. Exploiting coexpression gene network analysis on RNA sequencing data from failing human heart, we identified TXNDC5 (thioredoxin domain containing 5), a cardiac fibroblast (CF)-enriched endoplasmic reticulum protein, as a potential novel mediator of cardiac fibrosis, and we completed experiments to test this hypothesis directly. OBJECTIVE: The objective of this study was to determine the functional role of TXNDC5 in the pathogenesis of cardiac fibrosis. METHODS AND RESULTS: RNA sequencing and Western blot analyses revealed that TXNDC5 mRNA and protein were highly upregulated in failing human left ventricles and in hypertrophied/failing mouse left ventricle. In addition, cardiac TXNDC5 mRNA expression levels were positively correlated with those of transcripts encoding transforming growth factor ß1 and ECM proteins in vivo. TXNDC5 mRNA and protein were increased in human CF (hCF) under transforming growth factor ß1 stimulation in vitro. Knockdown of TXNDC5 attenuated transforming growth factor ß1-induced hCF activation and ECM protein upregulation independent of SMAD3 (SMAD family member 3), whereas increasing expression of TXNDC5 triggered hCF activation and proliferation and increased ECM protein production. Further experiments showed that TXNDC5, a protein disulfide isomerase, facilitated ECM protein folding and that depletion of TXNDC5 led to ECM protein misfolding and degradation in CF. In addition, TXNDC5 promotes hCF activation and proliferation by enhancing c-Jun N-terminal kinase activity via increased reactive oxygen species, derived from NAD(P)H oxidase 4. Transforming growth factor ß1-induced TXNDC5 upregulation in hCF was dependent on endoplasmic reticulum stress and activating transcription factor 6-mediated transcriptional control. Targeted disruption of Txndc5 in mice (Txndc5-/-) revealed protective effects against isoproterenol-induced cardiac hypertrophy, reduced fibrosis (by ≈70%), and markedly improved left ventricle function; post-isoproterenol left ventricular ejection fraction was 59.1±1.5 versus 40.1±2.5 (P<0.001) in Txndc5-/- versus wild-type mice, respectively. CONCLUSIONS: The endoplasmic reticulum protein TXNDC5 promotes cardiac fibrosis by facilitating ECM protein folding and CF activation via redox-sensitive c-Jun N-terminal kinase signaling. Loss of TXNDC5 protects against ß agonist-induced cardiac fibrosis and contractile dysfunction. Targeting TXNDC5, therefore, could be a powerful new therapeutic approach to mitigate excessive cardiac fibrosis, thereby improving cardiac function and outcomes in patients with heart failure.


Subject(s)
Cardiomyopathy, Hypertrophic/metabolism , Extracellular Matrix Proteins/metabolism , Fibroblasts/metabolism , Heart Failure/metabolism , Myocardium/pathology , Protein Disulfide-Isomerases/physiology , Protein Folding , Thioredoxins/physiology , Activating Transcription Factor 6/biosynthesis , Activating Transcription Factor 6/genetics , Animals , Cardiomyopathy, Hypertrophic/pathology , Cells, Cultured , Fibroblasts/pathology , Fibrosis/metabolism , Gene Expression Regulation , Heart Failure/chemically induced , Heart Failure/pathology , Humans , Isoproterenol/toxicity , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Myocardium/metabolism , NADPH Oxidase 4/biosynthesis , NADPH Oxidase 4/genetics , NIH 3T3 Cells , Oxidation-Reduction , Protein Disulfide-Isomerases/antagonists & inhibitors , Protein Disulfide-Isomerases/genetics , RNA Interference , RNA, Small Interfering/pharmacology , Thioredoxins/antagonists & inhibitors , Thioredoxins/genetics
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