Fine-tuning activation specificity of G-protein-coupled receptors via automated path searching.

Physics-based simulation methods can grant atomistic insights into the molecular origin of the function of biomolecules. However, the potential of such approaches has been hindered by their low efficiency, including in the design of selective agonists where simulations of myriad protein-ligand combinations are necessary. Here, we describe an automated input-free path searching protocol that offers (within 14 d using Graphics Processing Unit servers) a minimum free energy path (MFEP) defined in high-dimension configurational space for activating sphingosine-1-phosphate receptors (S1PRs) by arbitrary ligands. The free energy distributions along the MFEP for four distinct ligands and three S1PRs reached a remarkable agreement with Bioluminescence Resonance Energy Transfer (BRET) measurements of G-protein dissociation. In particular, the revealed transition state structures pointed out toward two S1PR3 residues F263/I284, that dictate the preference of existing agonists CBP307 and BAF312 on S1PR1/5. Swapping these residues between S1PR1 and S1PR3 reversed their response to the two agonists in BRET assays. These results inspired us to design improved agonists with both strong polar head and bulky hydrophobic tail for higher selectivity on S1PR1. Through merely three in silico iterations, our tool predicted a unique compound scaffold. BRET assays confirmed that both chiral forms activate S1PR1 at nanomolar concentration, 1 to 2 orders of magnitude less than those for S1PR3/5. Collectively, these results signify the promise of our approach in fine agonist design for G-protein-coupled receptors.

Mechanism of agonist-induced activation of the human itch receptor MRGPRX1.

Mas-related G-protein-coupled receptors X1-X4 (MRGPRX1-X4) are 4 primate-specific receptors that are recently reported to be responsible for many biological processes, including itch sensation, pain transmission, and inflammatory reactions. MRGPRX1 is the first identified human MRGPR, and its expression is restricted to primary sensory neurons. Due to its dual roles in itch and pain signaling pathways, MRGPRX1 has been regarded as a promising target for itch remission and pain inhibition. Here, we reported a cryo-electron microscopy (cryo-EM) structure of Gq-coupled MRGPRX1 in complex with a synthetic agonist compound 16 in an active conformation at an overall resolution of 3.0 Å via a NanoBiT tethering strategy. Compound 16 is a new pain-relieving compound with high potency and selectivity to MRGPRX1 over other MRGPRXs and opioid receptor. MRGPRX1 was revealed to share common structural features of the Gq-mediated receptor activation mechanism of MRGPRX family members, but the variable residues in orthosteric pocket of MRGPRX1 exhibit the unique agonist recognition pattern, potentially facilitating to design MRGPRX1-specific modulators. Together with receptor activation and itch behavior evaluation assays, our study provides a structural snapshot to modify therapeutic molecules for itch relieving and analgesia targeting MRGPRX1.

Structural insights into sphingosine-1-phosphate receptor activation.

As a critical sphingolipid metabolite, sphingosine-1-phosphate (S1P) plays an essential role in immune and vascular systems. There are five S1P receptors, designated as S1PR1 to S1PR5, encoded in the human genome, and their activities are governed by endogenous S1P, lipid-like S1P mimics, or nonlipid-like therapeutic molecules. Among S1PRs, S1PR1 stands out due to its nonredundant functions, such as the egress of T and B cells from the thymus and secondary lymphoid tissues, making it a potential therapeutic target. However, the structural basis of S1PR1 activation and regulation by various agonists remains unclear. Here, we report four atomic resolution cryo-electron microscopy (cryo-EM) structures of Gi-coupled human S1PR1 complexes: bound to endogenous agonist d18:1 S1P, benchmark lipid-like S1P mimic phosphorylated Fingolimod [(S)-FTY720-P], or nonlipid-like therapeutic molecule CBP-307 in two binding modes. Our results revealed the similarities and differences of activation of S1PR1 through distinct ligands binding to the amphiphilic orthosteric pocket. We also proposed a two-step "shallow to deep" transition process of CBP-307 for S1PR1 activation. Both binding modes of CBP-307 could activate S1PR1, but from shallow to deep transition may trigger the rotation of the N-terminal helix of Gαi and further stabilize the complex by increasing the Gαi interaction with the cell membrane. We combine with extensive biochemical analysis and molecular dynamic simulations to suggest key steps of S1P binding and receptor activation. The above results decipher the common feature of the S1PR1 agonist recognition and activation mechanism and will firmly promote the development of therapeutics targeting S1PRs.

Structure and function of eTudor domain containing TDRD proteins.

Tudor domain-containing (TDRD) proteins, as a family of evolutionarily conserved proteins, have been studied extensively in recent years in terms of their biological and biochemical functions. A major function of the TDRD proteins is to recognize the N-terminal arginine-rich motifs of the P-element-induced wimpy testis (PIWI) proteins via their conserved extended Tudor (eTudor or eTud) domains, which is essential in piRNA biogenesis and germ cell development. In this review, we summarize recent progress in the study of the TDRD proteins, and discuss the molecular mechanisms for the different binding selectivity of these eTudor domains to PIWI proteins based on the available binding and structural data. Understanding the binding differences of these TDRDs to PIWI proteins will help us better understand their functional differences and aid us in developing the target-specific therapeutics, because overexpression or mutations of the human TDRD proteins have been demonstrated to associate with various diseases.

Dual-target anti-Alzheimer's disease agents with both iron ion chelating and monoamine oxidase-B inhibitory activity.

MAO-B leads to an increase in the levels of hydrogen peroxide and oxidative free radicals, which contribute to the aetiology of the AD. Thus, both iron ion chelators and MAO-B inhibitors can be used to treat AD. Taking the coumarin derivatives and hydroxypyridinones as the lead compounds, a series of dual-target hybrids were designed and synthesised by Click Chemistry. The compounds were biologically evaluated for their iron ion chelating and MAO-B inhibitory activity. Most of the compounds displayed excellent iron ion chelating activity and moderate to good anti-MAO-B activity. Compounds 27b and 27j exhibited the most potent MAO-B inhibitory activity, with IC50 values of 0.68 and 0.86 µM, respectively. In summary, these dual-target compounds have the potential anti-AD activity.

The pyramids of Gizeh, reductionist research-based progress, unintended consequences and the complexity of medicine.

Bing graduated from the Medical Faculty at Erasmus University in Rotterdam, The Netherlands in 1988. He then completed a PhD in Medical Sciences (University of Calgary), internship (University of Regina) and surgical residency (University of Western Ontario) and post-residency clinical fellowships (University of Toronto and Harvard University) followed by a research post-doctoral fellowship (Department of Cell Biology, University of Toronto). Bing has been with the Roth | McFarlane Hand and Upper Limb Centre at St. Joseph's Health Centre since 1998. He is a Professor of Surgery and Medical Biophysics at Western University. His clinical practice focuses on hand and wrist surgery, microsurgical reconstruction and complex wound reconstruction, with a particular clinical and research interest in patients with Dupuytren's contracture. He is also interested in other fibrosing conditions, such as hypertrophic scarring. Bing was a Canadian Society for Clinical Investigation (CSCI) Member of Council 2004-2011and CSCI President 2009-2011.

Intra- and inter-isolate variation of ribosomal and protein-coding genes in Pleurotus: implications for molecular identification and phylogeny on fungal groups.

BACKGROUND: The internal transcribed spacer (ITS), RNA polymerase II second largest subunit (RPB2), and elongation factor 1-alpha (EF1α) are often used in fungal taxonomy and phylogenetic analysis. As we know, an ideal molecular marker used in molecular identification and phylogenetic studies is homogeneous within species, and interspecific variation exceeds intraspecific variation. However, during our process of performing ITS, RPB2, and EF1α sequencing on the Pleurotus spp., we found that intra-isolate sequence polymorphism might be present in these genes because direct sequencing of PCR products failed in some isolates. Therefore, we detected intra- and inter-isolate variation of the three genes in Pleurotus by polymerase chain reaction amplification and cloning in this study. RESULTS: Results showed that intra-isolate variation of ITS was not uncommon but the polymorphic level in each isolate was relatively low in Pleurotus; intra-isolate variations of EF1α and RPB2 sequences were present in an unexpectedly high amount. The polymorphism level differed significantly between ITS, RPB2, and EF1α in the same individual, and the intra-isolate heterogeneity level of each gene varied between isolates within the same species. Intra-isolate and intraspecific variation of ITS in the tested isolates was less than interspecific variation, and intra-isolate and intraspecific variation of RPB2 was probably equal with interspecific divergence. Meanwhile, intra-isolate and intraspecific variation of EF1α could exceed interspecific divergence. These findings suggested that RPB2 and EF1α are not desirable barcoding candidates for Pleurotus. We also discussed the reason why rDNA and protein-coding genes showed variants within a single isolate in Pleurotus, but must be addressed in further research. CONCLUSIONS: Our study demonstrated that intra-isolate variation of ribosomal and protein-coding genes are likely widespread in fungi. This has implications for studies on fungal evolution, taxonomy, phylogenetics, and population genetics. More extensive sampling of these genes and other candidates will be required to ensure reliability as phylogenetic markers and DNA barcodes.

Phylogenetic relationship of two popular edible Pleurotus in China, Bailinggu (P. eryngii var. tuoliensis) and Xingbaogu (P. eryngii), determined by ITS, RPB2 and EF1α sequences.

The aims of this study are to assess the utility of the internal transcribed spacer (ITS) region, and partial translation elongation factor (EF1α) and RNA polymerase II (RPB2) genes, for differentiation of Bailinggu, P. eryngii, and P. nebrodensis; to reconstruct phylogenetic relationships between the three species; and to confirm the taxonomic status of Bailinggu based on ribosomal and protein-coding genes. Pairwise genetic distances between Bailinggu, P. eryngii, and related Pleurotus strains were calculated by using the p-distance model, and molecular phylogeny of these isolates was estimated based on ITS, RPB2, and EF1α using maximum parsimony and Bayesian methods. Differences in ITS, RPB2, and EF1α sequences show that Bailinggu, P. eryngii, and P. nebrodensis are distinct at the species level. Phylogenetic analyses reveal that P. eryngii is closer to P. nebrodensis than to Bailinggu. Sequence analyses of ribosomal and protein-coding genes confirm that P. eryngii var. tuoliensis is identical to Bailinggu. P. eryngii var. tuoliensis should be raised to species level or a new name should be introduced for Bailinggu after a thorough investigation into Pleurotus isolates from Ferula in Xinjiang Province. This study helps to resolve uncertainty regarding Bailinggu, P. eryngii and P. nebrodensis, improving the resource management of these strains. ITS, EF1α, and RPB2 sequences can be used to distinguish Bailinggu, P. eryngii and P. nebrodensis as three different species, and P. eryngii var. tuoliensis should be the scientific name for Bailinggu at present.

Periostin induces fibroblast proliferation and myofibroblast persistence in hypertrophic scarring.

Hypertrophic scarring is characterized by the excessive development and persistence of myofibroblasts. These cells contract the surrounding extracellular matrix resulting in the increased tissue density characteristic of scar tissue. Periostin is a matricellular protein that is abnormally abundant in fibrotic dermis, however, its roles in hypertrophic scarring are largely unknown. In this report, we assessed the ability of matrix-associated periostin to promote the proliferation and myofibroblast differentiation of dermal fibroblasts isolated from the dermis of hypertrophic scars or healthy skin. Supplementation of a thin type-I collagen cell culture substrate with recombinant periostin induced a significant increase in the proliferation of hypertrophic scar fibroblasts but not normal dermal fibroblasts. Periostin induced significant increases in supermature focal adhesion formation, α smooth muscle actin levels and collagen contraction in fibroblasts cultured from hypertrophic scars under conditions of increased matrix tension in three-dimensional type-I collagen lattices. Inhibition of Rho-associated protein kinase activity significantly attenuated the effects of matrix-associated periostin on hypertrophic scar fibroblasts and myofibroblasts. Depletion of endogenous periostin expression in hypertrophic scar myofibroblasts resulted in a sustained decrease in α smooth muscle actin levels under conditions of reducing matrix tension, while matrix-associated periostin levels caused the cells to retain high levels of a smooth muscle actin under these conditions. These findings indicate that periostin promotes Rho-associated protein kinase-dependent proliferation and myofibroblast persistence of hypertrophic scar fibroblasts and implicate periostin as a potential therapeutic target to enhance the resolution of scars.

IGF-II and IGFBP-6 regulate cellular contractility and proliferation in Dupuytren's disease.

Dupuytren's disease (DD) is a common and heritable fibrosis of the palmar fascia that typically manifests as permanent finger contractures. The molecular interactions that induce the development of hyper-contractile fibroblasts, or myofibroblasts, in DD are poorly understood. We have identified IGF2 and IGFBP6, encoding insulin-like growth factor (IGF)-II and IGF binding protein (IGFBP)-6 respectively, as reciprocally dysregulated genes and proteins in primary cells derived from contracture tissues (DD cells). Recombinant IGFBP-6 inhibited the proliferation of DD cells, patient-matched control (PF) cells and normal palmar fascia (CT) cells. Co-treatments with IGF-II, a high affinity IGFBP-6 ligand, were unable to rescue these effects. A non-IGF-II binding analog of IGFBP-6 also inhibited cellular proliferation, implicating IGF-II-independent roles for IGFBP-6 in this process. IGF-II enhanced the proliferation of CT cells, but not DD or PF cells, and significantly enhanced DD and PF cell contractility in stressed collagen lattices. While IGFBP-6 treatment did not affect cellular contractility, it abrogated the IGF-II-induced contractility of DD and PF cells in stressed collagen lattices. IGF-II also significantly increased the contraction of DD cells in relaxed lattices, however this effect was not evident in relaxed collagen lattices containing PF cells. The disparate effects of IGF-II on DD and PF cells in relaxed and stressed contraction models suggest that IGF-II can enhance lattice contractility through more than one mechanism. This is the first report to implicate IGFBP-6 as a suppressor of cellular proliferation and IGF-II as an inducer of cellular contractility in this connective tissue disease.

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.

IGF2 expression and ß-catenin levels are increased in Frozen Shoulder Syndrome.

PURPOSE: Frozen Shoulder Syndrome is a fibrosis of the shoulder joint capsule that is clinically associated with Dupuytren's disease, a fibrosis of the palmar fascia. Little is known about any commonalities in the pathophysiology of these connective tissue fibroses. ß-catenin, a protein that transactivates gene expression, and levels of IGF2 mRNA, encoding insulin-like growth factor-II, are elevated in Dupuytren's disease. The aim of this study was to determine if correlating changes in ß-catenin levels and IGF2 expression are evident in Frozen Shoulder Syndrome. METHODS: Tissue from patients with Frozen Shoulder Syndrome and rotator cuff tear were obtained during shoulder arthroscopies. Total protein extracts were prepared from tissue aliquots and ß-catenin immunoreactivity was assessed by Western immunoblotting. In parallel, primary fibroblasts were derived from these tissues and assessed for IGF2 expression by quantitative PCR. RESULTS: ß-catenin levels were significantly increased in Frozen Shoulder Syndrome relative to rotator cuff tear when assessed by Western immunoblotting analyses. IGF2 mRNA levels were significantly increased in primary fibroblasts derived from frozen shoulder syndrome tissues relative to fibroblasts derived from rotator cuff tissues. CONCLUSIONS: As in Dupuytren's disease, ß-catenin levels and IGF2 expression are elevated in Frozen Shoulder Syndrome. These findings support the hypothesis that these connective tissue fibroses share a common pathophysiology.

The Fungal Secretory Peptide Micasin Induces Itch by Activating MRGPRX1/C11/A1 on Peripheral Neurons.

Pruritus is the leading symptom of dermatophytosis. Microsporium canis is one of the predominant dermatophytes causing dermatophytosis. However, the pruritogenic agents and the related molecular mechanisms of the dermatophyte M canis remain poorly understood. In this study, the secretion of the dermatophyte M canis was found to dose-dependently evoke itch in mice. The fungal peptide micasin secreted from M canis was then identified to elicit mouse significant scratching and itching responses. The peptide micasin was further revealed to directly activate mouse dorsal root ganglia neurons to mediate the nonhistaminergic itch. Knockout and antagonistic experiments demonstrated that MRGPRX1/C11/A1 rather than MRGPRX2/b2 activated by micasin contributed to pruritus. The chimeras and single-amino acid variants of MRGPRX1 showed that 3 domains (extracellular loop 3, transmembrane helical domain 3, and transmembrane helical domain 6) and 4 hydrophobic residues (Y99, F237, L240, and W241) of MRGPRX1 played the key role in micasin-triggered MRGPRX1 activation. Our study sheds light on the dermatophytosis-associated pruritus and may provide potential therapeutic targets and strategies against pruritus caused by dermatophytes.

Advances in the Mechanistic Study of the Control of Oxidative Stress Injury by Modulating HDAC6 Activity.

Oxidative stress is defined as an injury resulting from a disturbance in the dynamic equilibrium of the redox environment due to the overproduction of active/radical oxygen exceeding the antioxidative ability of the body. This is a key step in the development of various diseases. Oxidative stress is modulated by different factors and events, including the modification of histones, which are the cores of nucleosomes. Histone modification includes acetylation and deacetylation of certain amino acid residues; this process is catalyzed by different enzymes. Histone deacetylase 6 (HDAC6) is a unique deacetylating protease that also catalyzes the deacetylation of different nonhistone substrates to regulate various physiologic processes. The intimate relationship between HDAC6 and oxidative stress has been demonstrated by different studies. The present paper aims to summarize the data obtained from a mechanistic study of HDAC6 and oxidative stress to guide further investigations on mechanistic characterization and drug development.

Rapid separation and identification of 96 main constituents in Huanglian Jiedu decoction via ultra-high performance liquid chromatography-Orbitrap Fusion Tribrid mass spectrometer.

Huanglian Jiedu decoction is a widely used traditional Chinese medicine with a broad spectrum of therapeutic effects, including heat clearing, detoxification, and attenuation of inflammation. However, the composition of Huanglian Jiedu decoction is still unclear due to its complexity and limitations of analytical methods. In this study, we established a fast and reliable analytical method based on ultra-performance LC-Orbitrap Fusion Tribrid mass spectrometer for high-speed separation and structural identification of multiple compounds in Huanglian Jiedu decoction. The analysis was carried out using a Hypersil GOLD C18 column (2.1 × 100 mm, 1.9 µm) with gradient elution coupled to a high-definition mass spectrometer system operating in both positive and negative ESI modes. According to the chromatographic retention time, precise molecular weight, fragment ion peaks, and published data, the main chromatographic peaks were attributed to specific molecules whose chemical structures were determined. In total, 96 components were identified, including 34 flavonoids and their glycosides, 23 alkaloids, 18 organic acids, 13 terpenoids, and 8 miscellaneous compounds. This study revealed the detailed chemical composition of Huanglian Jiedu decoction, which is of great importance for quality control and further pharmacological and mechanistic studies.

Cell membrane-coated biomimetic magnetic nanoparticles for the bio-specific extraction of components from Gualou Guizhi decoction exhibiting activities against oxygen-glucose deprivation/reperfusion injury.

Gua-Lou-Gui-Zhi decoction (GLGZD) is a classical multiherb traditional Chinese medicine formula that has ameliorative effects on oxygen-glucose deprivation/reperfusion (OGD/R) injury and has been applied for the treatment of stroke in clinical practice; however, its active ingredients remain unknown. The aim of this study was to develop an effective method for screening for components of GLGZD with potential therapeutic activity against OGD/R injury. Brain microvascular endothelial cell membrane-coated magnetic beads (CMs@rBMECs-MBs) were incubated with the GLGZD extract; the bound material was eluted and the constituents were identified using solid phase extraction and ultra-performance liquid chromatography-Orbitrap Fusion Tribrid mass spectrometry (UPLC-Orbitrap Fusion Tribrid MS). The biological activities of the identified GLGZD components were analyzed using OGD/R-exposed brain endothelial cells. Seven compounds bound to the CMs@rBMECs-MBs were identified as gallic acid, paeoniflorin, liquiritigenin, isoliquiritigenin, liquiritin, isoliquiritin, and formononetin. Among them, six (except formononetin) protected brain endothelial cells against OGD/R injury in a concentration-dependent manner (20-120 µM; P < 0.01-0.05) and downregulated the expression of hypoxia-inducible factor-1α (P < 0.01) involved in the pathogenic mechanisms triggered by stroke. Our findings suggest that the screening of bioactive compounds using cell membrane-coated magnetic beads combined with solid phase extraction and UPLC-Orbitrap Fusion Tribrid MS is an effective method for the bio-specific extraction and identification of ingredients responsible for the therapeutic activity of traditional Chinese medicines.

Time to Stop Routinely Prescribing Opiates after Carpal Tunnel Release.

BACKGROUND: North American surgeons continue to routinely order narcotic medication for postoperative pain relief after carpal tunnel surgery. For some patients, this instigates persistent use. This double-blind, multicenter trial investigated whether over-the-counter medications were inferior to opioid pain control after carpal tunnel release. METHODS: Patients undergoing carpal tunnel release in five centers in Canada and the United States (n = 347) were randomly assigned to postoperative pain control with (opioid) hydrocodone/acetaminophen 5/325 mg versus over-the-counter ibuprofen/acetaminophen 600/325 mg. The two primary outcome measures were the Numeric Pain Rating Scale (0 to 10) and the six-item Patient-Reported Outcome Measurement Information System Pain Interference T-score. Secondary outcome measures were total medication used and overall satisfaction with pain medication management. RESULTS: The authors found no significant differences between opioid and over-the-counter patients in the Numeric Pain Rating Scale scores, Pain Interference T-scores, number of doses of medication, or patient satisfaction. The highest Numeric Pain Rating Scale group difference was the night of surgery, when opiate patients had 0.9/10 more pain than over-the-counter patients. The highest group difference in Pain Interference T-scores (2.1) was on the day of surgery, when the opiate patients had more pain interference than the over-the-counter group. Patient nationality or sex did not generate significant pain score differences. CONCLUSIONS: Pain management is not inferior for patients managed with over-the-counter acetaminophen/ibuprofen versus opioids. This study provides high-quality evidence that U.S. and Canadian surgeons should stop the routine prescription of narcotics after carpal tunnel surgery for patients who are not taking pain medicines daily before surgery. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, II.

[Study on methods of deproteinization from Phellinus baumii polysaccharide].

OBJECTIVE: To study and compare different methods and influencing factors of deproteinization from Phellinus baumii polysaccharide. METHODS: Sevag method and TCA method were used to remove protein from crude polysaccharide of Phellinus baumii, respectively. RESULTS: The effect of TCA method on removing protein was superior to that of Sevag method,and the optimum conditions of removing protein with TCA were as follows: 30 min treating time, 5% trichloroacetic acid,3 times treatemt. Under these conditions the rate of protein-removed was 82% and the rate of polysaccharide-lost was 10.8%. CONCLUSION: TCA method is the optimal mean for deproteinization from Phellinus baumii polysaccharide.

Protein biomarker analysis of primary Peyronie's disease cells.

INTRODUCTION: The molecular pathogenesis of Peyronie's 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.

Periostin differentially induces proliferation, contraction and apoptosis of primary Dupuytren's disease and adjacent palmar fascia cells.

Dupuytren's 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 Dupuytren's disease cord tissue relative to phenotypically normal palmar fascia. We demonstrate that the protein product of POSTN, periostin, is abundant in Dupuytren's 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.