David B. O'Gorman

Periostin Differentially Induces Proliferation, Contraction and Apoptosis of Primary Dupuytren's Disease and Adjacent Palmar Fascia Cells

Dupuytrens disease, (DD), is a fibroproliferative condition of the palmar fascia in the hand, typically resulting in permanent contracture of one or more fingers. This fibromatosis is similar to scarring and other fibroses in displaying excess collagen secretion and contractile myofibroblast differentiation. In this report we expand on previous data demonstrating that POSTN mRNA, which encodes the extra-cellular matrix protein periostin, is up-regulated in Dupuytrens disease cord tissue relative to phenotypically normal palmar fascia. We demonstrate that the protein product of POSTN, periostin, is abundant in Dupuytrens disease cord tissue while little or no periostin immunoreactivity is evident in patient-matched control tissues. The relevance of periostin up-regulation in DD was assessed in primary cultures of cells derived from diseased and phenotypically unaffected palmar fascia from the same patients. These cells were grown in type-1 collagen-enriched culture conditions with or without periostin addition to more closely replicate the in vivo environment. Periostin was found to differentially regulate the apoptosis, proliferation, alpha smooth muscle actin expression and stressed Fibroblast Populated Collagen Lattice contraction of these cell types. We hypothesize that periostin, secreted by disease cord myofibroblasts into the extra-cellular matrix, promotes the transition of resident fibroblasts in the palmar fascia toward a myofibroblast phenotype, thereby promoting disease progression.

Wnt expression is not correlated with β-catenin dysregulation in Dupuytren's Disease

BackgroundDupuytrens contracture or disease (DD) is a fibro-proliferative disease of the hand that results in finger flexion contractures. Increased cellular β-catenin levels have been identified as characteristic of this disease. As Wnts are the most widely recognized upstream regulators of cellular β-catenin accumulation, we have examined Wnt gene expression in surgical specimens and in DD-derived primary cell cultures grown in two-dimensional monolayer culture or in three-dimensional FPCL collagen lattice cultures.ResultsThe Wnt expression profile of patient-matched DD and unaffected control palmar fascia tissue was determined by a variety of complimentary methods; Affymetrix Microarray analysis, specific Wnt and degenerative primer-based Reverse Transcriptase (RT)-PCR, and Real Time PCR. Microarray analysis identified 13 Wnts associated with DD and control tissues. Degenerate Wnt RT-PCR analysis identified Wnts 10b and 11, and to a lesser extent 5a and 9a, as the major Wnt family members expressed in our patient samples. Competitive RT-PCR analysis identified significant differences between the levels of expression of Wnts 9a, 10b and 11 in tissue samples and in primary cell cultures grown as monolayer or in FPCL, where the mRNA levels in tissue > FPCL cultures > monolayer cultures. Real Time PCR data confirmed the down-regulation of Wnt 11 mRNA in DD while Wnt 10b, the most frequently isolated Wnt in DD and control palmar fascia, displayed widely variable expression between the methods of analysis.ConclusionThese data indicate that changes in Wnt expression per se are unlikely to be the cause of the observed dysregulation of β-catenin expression in DD.

Type-1 Collagen differentially alters β-catenin accumulation in primary Dupuytren's Disease cord and adjacent palmar fascia cells

BackgroundDupuytrens Disease (DD) is a debilitating contractile fibrosis of the palmar fascia characterised by excess collagen deposition, contractile myofibroblast development, increased Transforming Growth Factor-β levels and β-catenin accumulation. The aim of this study was to determine if a collagen-enriched environment, similar to in vivo conditions, altered β-catenin accumulation by primary DD cells in the presence or absence of Transforming Growth Factor-β.MethodsPrimary DD and patient matched, phenotypically normal palmar fascia (PF) cells were cultured in the presence or absence of type-1 collagen and Transforming Growth Factor-β1. β-catenin and α-smooth muscle actin levels were assessed by western immunoblotting and immunofluorescence microscopy.ResultsDD cells display a rapid depletion of cellular β-catenin not evident in patient-matched PF cells. This effect was not evident in either cell type when cultured in the absence of type-1 collagen. Exogenous addition of Transforming Growth Factor-β1 to DD cells in collagen culture negates the loss of β-catenin accumulation. Transforming Growth Factor-β1-induced α-smooth muscle actin, a marker of myofibroblast differentiation, is attenuated by the inclusion of type-1 collagen in cultures of DD and PF cells.ConclusionOur findings implicate type-1 collagen as a previously unrecognized regulator of β-catenin accumulation and a modifier of TGF-β1 signaling specifically in primary DD cells. These data have implications for current treatment modalities as well as the design of in vitro models for research into the molecular mechanisms of DD.

Genipin-Cross-linked Electrospun Collagen Fibers

The fabrication of a fibrous collagen scaffold using electrospinning is desirable for tissue-engineering applications. Previously, electrospun collagen fibers were shown to be unstable in aqueous environments and, therefore, cross-linking is essential to stabilize these fibers. In this study genipin, a significantly less cytotoxic cross-linking agent compared to glutaraldehyde, was used to cross-link electrospun collagen fibers. The significance of this research lies in the use of four alcohol/water solvent systems to carry out the crosslinking reaction to maintain fibrous morphology during cross-linking. The four cross-linking conditions established were: (1) ethanol, 5% water and 3 days, (2) ethanol, 3% water and 5 days, (3) ethanol, 5% water and 5 days, and (4) isopropanol, 5% water and 5 days at a genipin concentration of 0.03 M. Results illustrated that genipin-cross-linking was effective in maintaining collagen fiber integrity in aqueous and cell culture media environments for up to 7 days. In addition, it was shown that fiber swelling could be controlled by using different cross-linking conditions. Swelling of cross-linked fibers immersed in Dulbeccos modified eagle medium for 7 days ranged from 0 to 59 ± 4%. The cross-linked fibers were analyzed using scanning electron microscopy, Fourier transform infrared spectroscopy and ninhydrin assay. Finally, studies using primary human fibroblasts indicated good cell adhesion to these scaffolds. Overall, our data suggest that these stabilized fibrous collagen scaffolds provide a promising environment for tissue-regeneration applications.

Protein Biomarker Analysis of Primary Peyronie's Disease Cells

INTRODUCTION The molecular pathogenesis of Peyronies Disease (PD) remains unclear more than 250 years after its initial description. Because of this, no test is currently available to accurately predict PD progression among those affected. AIM To investigate the expression of wound healing and fibrosis-associated proteins in primary cell cultures of PD fibroblasts to determine whether altered protein expression patterns can be used as predictors of clinical course and natural history. METHODS Primary cell cultures derived from normal Tunica albuginea tissue and PD plaque tissue were examined by immuno-cytochemistry. Protein expression profiles were analyzed by Surface-Enhanced Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (SELDI-TOF-MS) and Western immunoblotting. MAIN OUTCOME MEASURES Expression of wound healing and fibrosis-associated proteins and protein expression patterns were assessed. RESULTS Statistically significant increases in smooth muscle alpha-actin, beta-catenin, and Heat shock proteins (Hsp47) were identified in cells derived from PD relative to cells derived from normal Tunica albuginea tissue. Changes in TGFbeta-1 receptor and Fibronectin were also observed. In addition, altered expression of additional as yet unidentified proteins at 4.7, 8.9, 10.8, 16.8, and 76.8 kDa were detected by complementary SELDI-TOF-MS approaches. CONCLUSIONS Primary cells derived from PD plaques display up-regulated expression of several proteins that are established components of fibrosis and wound healing. In addition, changes in other, as yet unidentified proteins were measured. It will be of interest to conduct further studies to see whether these dysregulated protein peaks represent potential biological markers of disease progression.

Neer Award 2017: A rapid method for detecting Propionibacterium acnes in surgical biopsy specimens from the shoulder

BACKGROUND Propionibacterium (P) acnes infection of the shoulder after arthroplasty is a common and serious complication. Current detection methods for P acnes involve anaerobic cultures that require prolonged incubation periods (typically 7-14 days). We have developed a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) approach that sensitively and specifically identifies P acnes in tissue specimens within a 24-hour period. METHODS Primers were designed to amplify a unique region of the 16S rRNA gene in P acnes that contained a unique HaeIII restriction enzyme site. PCR and RFLP analyses were optimized to detect P acnes DNA in in vitro cultures and in arthroscopic surgical biopsy specimens from patients with P acnes infections. RESULTS A 564 base-pair PCR amplicon was derived from all of the known P acnes strains. HaeIII digests of the amplicon yielded a restriction fragment pattern that was unique to P acnes. P acnes-specific amplicons were detected in as few as 10 bacterial cells and in clinical biopsy specimens of infected shoulder tissues. CONCLUSION This PCR-RFLP assay combines the sensitivity of PCR with the specificity of RFLP mapping to identify P acnes in surgical isolates. The assay is robust and rapid, and a P acnes-positive tissue specimen can be confirmed within 24 hours of sampling, facilitating treatment decision making, targeted antibiotic therapy, and monitoring to minimize implant failure and revision surgery.

A novel mass spectrometry-based assay for GSK-3β activity

BackgroundAs a component of the progression from genomic to proteomic analysis, there is a need for accurate assessment of protein post-translational modifications such as phosphorylation. Traditional kinase assays rely heavily on the incorporation of γ-P32 radiolabeled isotopes, monoclonal anti-phospho-protein antibodies, or gel shift analysis of substrate proteins. In addition to the expensive and time consuming nature of these methods, the use of radio-ligands imposes restrictions based on the half-life of the radionucleotides and pose potential health risks to researchers. With the shortcomings of traditional assays in mind, the aim of this study was to develop a high throughput, non-radioactive kinase assay for screening Glycogen Synthase Kinase-3beta (GSK-3β) activity.ResultsSynthetic peptide substrates designed with a GSK-3β phosphorylation site were assayed with both recombinant enzyme and GSK-3β immunoprecipitated from NIH 3T3 fibroblasts. A molecular weight shift equal to that of a single phosphate group (80 Da.) was detected by surface enhanced laser desorption/ionization time of flight mass spectrometry (SELDI-TOF-MS) in a GSK-3β target peptide (2B-Sp). Not only was there a dose-dependent response in molecular weight shift to the amount of recombinant GSK-3β used in this assay, this shift was also inhibited by lithium chloride (LiCl), in a dose-dependent manner.ConclusionWe present here a novel method to sensitively measure peptide phosphorylation by GSK-3β that, due to the incorporation of substrate controls, is applicable to either purified enzyme or cell extracts. Future studies using this method have the potential to elucidate the activity of GSK-3β in vivo, and to screen enzyme activity in relation to a variety of GSK-3β related disorders.

Monitoring Collagen Synthesis in Fibroblasts Using Fluorescently Labeled tRNA Pairs

There is a critical need for techniques that directly monitor protein synthesis within cells isolated from normal and diseased tissue. Fibrotic disease, for which there is no drug treatment, is characterized by the overexpression of collagens. Here, we use a bioinformatics approach to identify a pair of glycine and proline isoacceptor tRNAs as being specific for the decoding of collagen mRNAs, leading to development of a FRET‐based approach, dicodon monitoring of protein synthesis (DiCoMPS), that directly monitors the synthesis of collagen. DiCoMPS aimed at detecting collagen synthesis will be helpful in identifying novel anti‐fibrotic compounds in cells derived from patients with fibrosis of any etiology, and, suitably adapted, should be widely applicable in monitoring the synthesis of other proteins in cells. J. Cell. Physiol. 229: 1121–1129, 2014.

Cutibacterium acnes and the shoulder microbiome

BACKGROUND Advances in DNA sequencing technologies have made it possible to detect microbial genome sequences (microbiomes) within tissues once thought to be sterile. We used this approach to gain insights into the likely sources of Cutibacterium acnes (formerly Propionibacterium acnes) infections within the shoulder. METHODS Tissue samples were collected from the skin, subcutaneous fat, anterior supraspinatus tendon, middle glenohumeral ligament, and humeral head cartilage of 23 patients (14 male and 9 female patients) during primary arthroplasty surgery. Total DNA was extracted and microbial 16S ribosomal RNA sequencing was performed using an Illumina MiSeq system. Data analysis software was used to generate operational taxonomic units for quantitative and statistical analyses. RESULTS After stringent removal of contamination, genomic DNA from various Acinetobacter species and from the Oxalobacteraceae family was identified in 74% of rotator cuff tendon tissue samples. C acnes DNA was detected in the skin of 1 male patient but not in any other shoulder tissues. CONCLUSION Our findings indicate the presence of a low-abundance microbiome in the rotator cuff and, potentially, in other shoulder tissues. The absence of C acnes DNA in all shoulder tissues assessed other than the skin is consistent with the hypothesis that C acnes infections are derived from skin contamination during surgery and not from opportunistic expansion of a resident C acnes population in the shoulder joint.

The cellular microenvironment: a new target in the search for cellular and molecular treatment for Dupuytren’s disease

Introduction: Dupuytren’s disease (DD) is a debilitating fibrotic disease of the palmar fascia (PF) that leads to irreversible flexion contractures of the fingers and loss of dexterity and hand function. Currently, DD is treated by surgical or enzymatic elimination of the contracted PF using treatment approaches that carry significant morbidity and high recurrence rates. Areas covered: This review is limited to the most recent data pertaining to the cellular and molecular biology of DD. It does not review data on the clinical management of DD. Expert opinion: The current gold standard of treatment of DD is (sub)-total resection of the diseased, contracted palmar fascia. Like other less invasive treatment alternatives, such as needle aponeurotomy or clostridial collagenase digestion of the contracted cords, fasciectomy is associated with high disease recurrence rates. This review summarizes the published evidence that changes in the cellular microenvironment can modify established signaling pathways and gene expression profiles in DD cells. These findings have implications for research programs that aim to identify disease-associated cytokines or growth factors as targets for molecular therapy. A theoretical framework is described, suggesting that future research into new non-surgical treatment approaches for DD should include consideration of the modifying influences of the DD microenvironment. The ultimate aim of DD research should be the development of a treatment that establishes normal cellular homeostasis in the PF and not simply the elimination of PF contractures.