Microfibrillar-associated Protein Research Articles

Essential role of microfibrillar-associated protein 4 in human cutaneous homeostasis and in its photoprotection

UVB-induced cutaneous photodamage/photoaging is characterized by qualitative and quantitative deterioration in dermal extracellular matrix (ECM) components such as collagen and elastic fibers. Disappearance of microfibrillar-associated protein 4 (MFAP-4), a possible limiting factor for cutaneous elasticity, was documented in photoaged dermis, but its function is poorly understood. To characterize its possible contribution to photoprotection, MFAP-4 expression was either augmented or inhibited in a human skin xenograft photodamage murine model and human fibroblasts. Xenografted skin with enhanced MFAP-4 expression was protected from UVB-induced photodamage/photoaging accompanied by the prevention of ECM degradation and aggravated elasticity. Additionally, remarkably increased or decreased fibrillin-1-based microfibril development was observed when fibroblasts were treated with recombinant MFAP-4 or with MFAP-4-specific siRNA, respectively. Immunoprecipitation analysis confirmed direct interaction between MFAP-4 and fibrillin-1. Taken together, our findings reveal the essential role of MFAP-4 in photoprotection and offer new therapeutic opportunities to prevent skin-associated pathologies.

Microfibrillar-associated protein 5 is linked with markers of obesity-related extracellular matrix remodeling and inflammation

Objective:Microfibrillar-associated protein 5 (MFAP5) is an extracellular matrix (ECM) glycoprotein, which is colocalized with microfibrils in elastin networks. Its function in adipose tissue (AT) is not known. We have recently shown that the expression of MFAP5 is downregulated in AT along with weight reduction (WR) in persons with metabolic syndrome (MetS). The aim of this work was to study whether the change of MFAP5 mRNA expression in response to WR is associated with markers of adiposity, glucose metabolism and insulin resistance in human AT.Design:Weight reduction intervention study in parallel study design (The Genobin study). Altogether 46 obese subjects with impaired glucose tolerance and features of MetS were randomized to a WR (n=28) or a control group (n=18) lasting for 33 weeks.Measurements:Circulating glucose and insulin concentrations were measured and subcutaneous AT biopsies were performed before and after the intervention. The mRNA expression was studied by quantitative real-time PCR (QPCR).Results:QPCR of human AT biopsy samples confirmed that MFAP5 is highly expressed in AT and its expression is decreased during WR. The mRNA expression of MFAP5 correlated positively with body mass index, and the change in MFAP5 mRNA expression during WR correlated positively with the change of body fat mass. Furthermore, the MFAP5 mRNA expression correlated negatively with circulating fasting concentrations of adiponectin and interleukin (IL)-1β and positively with leptin, insulin and IL-1Ra levels. In addition, the MFAP5 mRNA expression correlated positively with the mRNA expressions of peroxisome proliferator-activated receptor gamma, cyclin D2 and A disintegrin and metalloproteinase domain 12, genes involved in AT remodeling.Conclusion:This study demonstrates that MFAP5 is highly expressed in human AT and is correlated with markers of insulin resistance. Furthermore, it is possible that MFAP5 is related to ECM remodeling during development of obesity.

Whole-genome expression profiling of brain metastases from melanoma (BrMM) provides preliminary insights into its biology and mechanisms of development.

8515 Background: BrMM accounts for a major fraction of the mortality from melanoma and little is known about the biology of BrMM or its association with extracranial metastases (EcMM) and primary melanoma (PrM). This would provide insights about BrMM pathogenesis and lead to better prognostic and therapeutic targets. We hypothesize that BrMM differ from EcMM and PrMs in gene expression levels. These signatures will provide insight to the pathogenesis and lead to better prognostic and therapeutic targets. Methods: We have performed whole genome expression profiling (DASL assay, Illumina; 28,688 genes) of formalin-fixed paraffin-embedded (FFPE) tissue blocks corresponding to paired specimens (BrMM and EcMM) from patients (pts) undergoing craniotomy at UPCI. We performed class comparison analysis using paired t tests to identify differentially expressed genes. Results are presented as the ratio of the geometric mean of EcMM/BrMM. Results: Paired analysis of FFPE tumor blocks from 12 pts has been accomplished (n=24). 187 genes were differentially (p<0.05) expressed between BrMM and EcMM. The table shows gene categories of most significantly dysregulated genes. We confirmed that upregulation of GFAP in BrMM derives from melanoma cells and not normal brain using immunohistochemical analysis of GFAP protein in BrMM, EcMM, and PrM from the same pt. Conclusions: The upregulation of neuronal differentiation genes in BrMM underscores the potential of melanoma cells to transdifferentiate (plasticity) although the clinical significance is currently unknown. The upregulation of immune tolerance and ECM remodeling genes in EcMM challenges the prevailing notion that BrMM is the last step in the metastatic cascade. Profiling PrM is underway. Function EcMM/BrMM Extracellular matrix (ECM) remodeling Cartilage intermediate protein 6.2 Matrix metallopeptidase 9 5.3 Cartilage oligomeric matrix protein 4.9 Microfibrillar-associated protein 5 3.2 Neural differentiation/function Gliomedin 0.15 Glutamate receptor, metabotropic 3 0.23 Glial fibriallary acidic protein (GFAP) 0.26 Immune tolerance Chemokine ligand 19 3.6 Chemokine ligand 21 3.6 CTLA4 2.4

Transcriptional Effects of Dietary Exposure of Oil-Contaminated Calanus finmarchicus in Atlantic Herring (Clupea harengus)

Suppression subtractive hybridization (SSH) cDNA library construction and characterization was used to identify differentially regulated transcripts from oil exposure in liver of male Atlantic herring (Clupea harengus) fed a diet containing 900 mg crude oil/kg for 2 mo. In total, 439 expressed sequence tags (EST) were sequenced, 223 from the forward subtracted library (enriched for genes putatively upregulated by oil exposure) and 216 from the reverse subtracted library (enriched for genes putatively downregulated by oil exposure). Follow-up reverse-transcription (RT) quantitative polymerase chain reaction (qPCR) analyses of gene transcription were conducted on additional herring exposed to food containing 9 (low), 90 (medium), and 900 (high) mg crude oil/kg feed for 2 mo. Chronic exposure of Atlantic herring to an oil-contaminated diet mediated upregulation of transcripts encoding antifreeze proteins, proteins in the classical complement pathway (innate immunity), and iron-metabolism proteins. Gene ontology (GO) analysis showed that “cellular response to stress,” “regulation to biological quality,” “response to abiotic stimuli,” and “temperature homeostasis” were the most affected go at the biological processes level, and “carbohydrate binding,” “water binding,” and “ion binding” at the molecular function level. Of the genes examined with RT-qPCR, CYP1A, antifreeze protein, retinol binding protein 1, deleted in malignant brain tumor 1, and ovary-specific C1q-like factor demonstrated a significant upregulation. Myeloid protein 1, microfibrillar-associated protein 4, WAP65, and pentraxin were downregulated in liver of fish from the high exposure group. In conclusion, this study suggests that 2 mo of oil exposure affected genes encoding proteins involved in temperature homeostasis and possible membrane stability in addition to immune-responsive proteins in Atlantic herring.

Microfibrillar-associated protein 4 (MFAP4) genes in catfish play a novel role in innate immune responses

The lectin pathway of the complement system is characterized by two groups of soluble pattern recognition molecules, mannose-binding lectins (MBLs) and ficolins. These molecules recognize and bind carbohydrates in pathogens and activate complement leading to opsonization, leukocyte activation, and direct pathogen killing. While MBLs have been reported in many fish species, ficolins do not appear to be present in the teleost lineage, despite their importance in invertebrate and higher vertebrate innate immunity. A protein with a similar fibrinogen-like domain, microfibrillar-associated protein 4, MFAP4, is present in fish, albeit with no described immune function. We examined whether MFAP4 genes in fish may potentially act as pathogen receptors in the absence of ficolin. We isolated and characterized five MFAP4 genes from channel catfish. Linkage mapping and phylogenetic analysis indicated that at least three of the catfish MFAP4 genes are tightly clustered on a single chromosome, suggesting that they may have arisen through tandem duplication. Divergent, duplicated families of MFAP4 genes are also present in other teleost species. Expression analysis of the catfish MFAP4 transcripts revealed unique patterns of homeostatic expression among the genes in gill, spleen, skin, liver, and muscle. Expression of the five MFAP4 transcripts showed significant changes in expression as soon as 4 h after infection with either Edwardsiella ictaluri or Flavobacterium columnare with modulation of expression continuing up to 7 d following pathogen exposure. Several different tissues and gene-specific patterns were captured and transcript expression changes of >30-fold were observed over the course of the bacterial challenges. Our results suggest a novel role for MFAP4 in teleost immune responses.

Peripheral Blood Mononuclear Cell Gene Array Profiles in Patients With Overactive Bladder

To investigate the utility of using peripheral blood mononuclear cells (PBMC) as a marker for patients with overactive bladder (OAB). Patients with OAB may suffer from varying degrees of symptoms such as frequency, urgency, nocturia, and incontinence; however, there is no definitive test for OAB at this time. Questionnaires may provide useful tools for screening patients for OAB but often clinicians may need to rely on more invasive procedures to confirm the diagnosis. We have previously demonstrated that PBMC can provide a reporter function in solid organ retroperitoneal disease. Twenty-one patients were assessed for OAB. PBMC was obtained from whole blood of the patients, and RNA was subjected to microarray gene chip analysis. Microarray analysis revealed that 16 genes were differentially regulated (8 upregulated and 8 downregulated) in all patients with OAB in comparison with healthy controls. A sex-based analysis demonstrated 74 genes that were differentially regulated in males (25 upregulated and 49 downregulated), and 30 in females (13 upregulated and 17 downregulated). Of these platelet-derived growth factors, microfibrillar-associated protein and tropomyosin were downregulated in all sets that were analyzed. Microarray analysis revealed many genes that were differentially regulated in PBMC from OAB patients, including regulatory elements and genes encoding structural proteins, which may be important in regulating structural integrity of the bladder and supporting tissues. These data suggest that PBMC can provide a reporter function for patients with OAB and may serve as a diagnostic marker and elucidate genes involved in this condition.

PERIPHERAL BLOOD MONONUCLEAR CELL GENE ARRAY PROFILES IN PATIENTS WITH OVERACTIVE BLADDER (132.8)

Abstract Introduction: Overactive bladder (OAB) confirmation of disease often requires invasive approaches. We have previously demonstrated that peripheral blood mononuclear cells (PBMC) can provide a reporter function in solid organ retroperitoneal disease. Here we investigated the utility of using PBMC as a marker for patients with OAB. Methods: 21 patients were assessed for OAB and structural integrity. Patients with a history of recent surgery or infection were excluded. Whole blood was obtained from patients and appropriately matched controls (n=6) and PBMC were separated by density centrifugation. RNA was isolated from PBMC and converted to aRNA and subjected to microarray analysis (human U133A 2.0). Results: Microarray analysis revealed that 16 genes were differentially regulated (8 upregulated and 8 downregulated) in all patients with OAB compared with controls. Sex based analysis demonstrated 74 genes differentially regulated in males (25 upregulated and 49 downregulated), and 30 in females (13 upregulated and 17 downregulated). Of these, PDGF, MFAP3L, a microfibrillar-associated protein, and TPM1 (tropomyosin) were downregulated in all sets analyzed. Conclusions: Microarray analysis revealed many genes which were differentially regulated in PBMC from OAB patients, including regulatory/structural genes; PDGF, MFAP and TPM1 may be important in regulating structural integrity of bladder and supporting tissues. These data suggest that blood derived leukocytes can provide a reporter function for patients with solid organ disease and may serve as a diagnostic marker and/or monitor response to therapy.