Α1 Chain Research Articles

Functional Properties of Collagen Extracted From Catfish ( Silurus triostegus) Bone

Back ground: Collagen accounts for 25percent of all proteins found in vertebrates. The words "collagen"is created with Greek words "kolla" and "genos," which respectively mean "glue" and "formation." It hasa wide range of biological and pharmacological uses. Pig and cow skins provide the majority of thecollagen. Utilizing animal collagen has been restricted as a result of epidemics of certain animal diseasesincluding foot-and-mouth disease (FMD) and bovine spongiform encephalopathy (BSE) (FMD), whichpose a risk of transmission to humansObjective: The goal of this study is to extract collagen from catfish bone.Material and methods: Catfish (Silurus triostegus) bone was used to extract collagen that has beenpepsinized and acid-solubilized collagen (ASC) (PSC). The extracts' proximate composition (moisture,protein, fat, and ash) was measured, and dry weight was used to compute the yield of ASC and PSC. Themolecular weight of experimental collagen ranged from 97 to 200 KD, according to the SDS-PAGEpattern. In order to identify bone collagen, the Fourier Transform Infrared (FTIR) spectra analysis for theacquired ASC and PSC, as well as the standard collagen (type I, II), was used. Using a scanning electronmicroscope (SEM, the morphological structure of ASC and PSC was revealed), and the diffraction angles(2 θ) of ASC and PSC were determined using X-ray analysis. For quality control, the HPLC techniquewas used to determine the collagen.Rustles: The proximate composition of ASC and PSC bone of catfish. The ASC bone of catfish containedmoisture (75.22%), good amount of protein (16.65%) , fat (2.40%) and ash content (0.28 %), While thePSC bone had slightly lower moisture (68.50%) than ASC, it had higher protein (19.93%), fat (1.825%),and ash (0.58%) levels ,HPLC SEM ,FTIR ,Electrophoresis, X-ray.Conclusion: Fish bone was promising sources for preparing collagen, acid soluble collagen (ASC),pepsin soluble collagen (PSC) were successfully extracted by two methods. The collagen extracted frombone catfish, was of type I collagen, which are composed two α1, one α2 chains, and β chains as shownby SDS-PAGE patterns.

Knockout of Purinergic P2Y6 Receptor Fails to Improve Liver Injury and Inflammation in Non-Alcoholic Steatohepatitis.

Nonalcoholic steatohepatitis (NASH) is a disease that progresses from nonalcoholic fatty liver (NAFL) and which is characterized by inflammation and fibrosis. The purinergic P2Y6 receptor (P2Y6R) is a pro-inflammatory Gq/G12 family protein-coupled receptor and reportedly contributes to intestinal inflammation and cardiovascular fibrosis, but its role in liver pathogenesis is unknown. Human genomics data analysis revealed that the liver P2Y6R mRNA expression level is increased during the progression from NAFL to NASH, which positively correlates with inductions of C-C motif chemokine 2 (CCL2) and collagen type I α1 chain (Col1a1) mRNAs. Therefore, we examined the impact of P2Y6R functional deficiency in mice crossed with a NASH model using a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD). Feeding CDAHFD for 6 weeks markedly increased P2Y6R expression level in mouse liver, which was positively correlated with CCL2 mRNA induction. Unexpectedly, the CDAHFD treatment for 6 weeks increased liver weights with severe steatosis in both wild-type (WT) and P2Y6R knockout (KO) mice, while the disease marker levels such as serum AST and liver CCL2 mRNA in CDAHFD-treated P2Y6R KO mice were rather aggravated compared with those of CDAHFD-treated WT mice. Thus, P2Y6R may not contribute to the progression of liver injury, despite increased expression in NASH liver.

Identification and functional characterization of a novel truncating splicing variant in COL4A5 gene causes X-linked Alport syndrome with astigmatism.

Identification and functional characterization of a novel truncating splicing variant in COL4A5 gene causes X-linked Alport syndrome with astigmatism.

Calcipotriol Attenuates Form Deprivation Myopia Through a Signaling Pathway Parallel to TGF-β2–Induced Increases in Collagen Expression

To determine the role of calcipotriol, a vitamin D3 analogue, in myopia development and altering the expression of scleral α1 chain of type I collagen (Col1α1) in mice. We also aimed to identify if the signaling pathway mediating the above changes is different from the one involved in transforming growth factor β2 (TGF-β2)-mediated increases of COL1A1 in cultured human scleral fibroblasts (HSFs). C57BL/6J mice were either intraperitoneally injected with calcipotriol and subjected to form deprivation (FD) or exposed to normal refractive development for 4weeks. Scleral vitamin D receptor (Vdr) expression was knocked down using a Sub-Tenon's capsule injection of an adeno-associated virus-packaged short hairpin RNA (AAV8-shRNA). Refraction and biometric measurements evaluated myopia development. A combination of knockdown and induction strategies determined the relative contributions of the vitamin D3 and the TGF-β2 signaling pathways in modulating COL1A1 expression in HSFs. Calcipotriol injections suppressed FD-induced myopia (FDM), but it had no significant effect on normal refractive development. AAV8-shRNA injection reduced Vdr mRNA expression by 42% and shifted the refraction toward myopia (-3.15 ± 0.99D, means ± SEM) in normal eyes. In HSFs, VDR knockdown reduced calcipotriol-induced rises in COL1A1 expression, but it did not alter TGF-β2-induced increases in COL1A1 expression. Additionally, TGF-β2 augmented calcipotriol-induced rises in COL1A1 expression. TGF-β receptor (TGFBRI/II) knockdown blunted TGF-β2-induced increases in COL1A1 expression, whereas calcipotriol-induced increases in VDR and COL1A1 expression levels were unaltered. Scleral vitamin D3 inhibits myopia development in mice, potentially by activating a VDR-dependent signaling pathway and increasing scleral COL1A1 expression levels.

Stiff substrates inhibit collagen accumulation via integrin α2β1, FAK and Src kinases in human atrial fibroblast and myofibroblast cultures derived from patients with aortal stenosis

The aim of the study was to confirm whether cell substrate stiffness may participate in the regulation of fibrosis. The involvement of integrin α2β1, focal adhesion kinase (FAK) and Src kinase in signal transmission was investigated. Human atrial fibroblasts and myofibroblasts were cultured in both soft (2.23 ± 0.8 kPa) and stiff (8.28 ± 1.06 kPa) polyacrylamide gels. The cells were derived from the right atrium of patients with aortal stenosis undergoing surgery. The isolated cells, identified as fibroblasts or myofibroblasts, were stained positively with α smooth muscle actin, vimentin and desmin. The cultures settled on stiff gel demonstrated lower intracellular collagen and collagen type I telopeptide (PICP) levels; however, no changes in α1 chain of procollagen type I and III expression were noted. Inhibition of α2β1 integrin by TC-I 15 (10−7 and 10−8 M) or α2 integrin subunit silencing augmented intracellular collagen level. Moreover, FAK or Src kinase inhibitors increased collagen content within the culture. Lower TIMP4 secretion was reported within the stiff gel cultures but neither MMP 2 nor TIMP-1, 2 or 3 release was altered. The stiff substrate cultures also demonstrated lower interleukin-6 release. Substrate stiffness modified collagen deposition within the atrial fibroblast and myofibroblast cultures. The elasticity of the cellular environment exerts a regulatory influence on both synthesis and breakdown of collagen. Integrin α2β1, FAK and Src kinase activity participates in signal transmission, which may influence fibrosis in the atria of the human heart.

A deep intronic splice variant of the COL4A5 gene in a Chinese family with X-linked Alport syndrome.

X-linked Alport syndrome (XLAS) is caused by pathogenic variants in COL4A5 and is characterized by progressive kidney disease, hearing loss, and ocular abnormalities.The aim of this study was to identify gene mutations in a Chinese family with XLAS, confirm a diagnosis, and provide an accurate genetic counseling. The proband was a 5-year-old male with microscopic hematuria and a family history of renal disease in 5 relatives.His relatives had microhematuria with or without proteinuria. His maternal uncle developed renal failure at the age of 35 years. He was evaluated by renal biopsy,whole-exome sequencing (WES) and whole-genome sequencing (WGS) for Alport syndrome. RT-PCR and cDNA Sanger sequencing were performed on RNA extracted from the skin of the proband. Then, a splicing reporter minigene assay was used to examine the effect of the variation on the splicing of the primary transcript in transfected cells. Pathological examination of the kidney of the proband revealed diffuse thinning of the glomerular basement membrane, and immunofluorescence analysis indicated normal expression of the α5 chain in the basement membrane. No phenotype-associated candidate variant was detected in the proband via WES. A novel deep intronic COL4A5 variant (c.385-716G > A), which is segregated with disease in this family, was identified using WGS. In-vitro minigene assay and in-vivo RT-PCR analysis demonstrated that the variant could produce both normal and abnormal transcripts. The abnormal transcripts showed that the variant activated a cryptic splice site, introducing a 147 bp pseudoexon into the mRNA sequence and consequently generating a premature termination codon (p.G129Afs*38) and leading to frameshifting and truncation of the α5 (collagen IV) protein. This is the first report of the novel c.385-716G > A splicing mutation in the COL4A5 gene, which illustrates the importance of performing WGS to find additional mutations in WES-negative patients with highly suspected forms of genetic diseases. The same results obtained from the in-vitro and in-vivo splicing experiments confirm the consistency between the minigene assay and RT-PCR analysis. In addition, this study highlights the importance of functional analysis in diagnosis and genetic counseling in AS.

Potential implications of the glycosylation patterns in collagen α1(I) and α2(I) chains for fibril assembly and growth

O-Glycosylation of hydroxylysine (Hyl) in collagen occurs at an early stage of biosynthesis before the triple-helix has formed. This simple post-translational modification (PTM) of lysine by either a galactosyl or glucosylgalactosyl moiety is highly conserved in collagens and depends on the species, type of tissue and the collagen amino acid sequence. The structural/functional reason why only specific lysines are modified is poorly understood, and has led to increased efforts to map the sites of PTMs on collagen sequences from different species and to ascertain their potential role in vivo. To investigate this, we purified collagen type I (Col1) from the skins of four animals, then used mass spectrometry and proteomic techniques to identify lysines that were oxidised, galactosylated, glucosylgalactosylated, or glycated in its mature sequence. We found 18 out of the 38 lysines in collagen type Iα1, (Col1A1) and 7 of the 30 lysines in collagen type Iα2 (Col1A2) were glycosylated. Six of these modifications had not been reported before, and included a lysine involved in crosslinking collagen molecules. A Fourier transform analysis of the positions of the glycosylated hydroxylysines showed they display a regular axial distribution with the same d-period observed in collagen fibrils. The significance of this finding in terms of the assembly of collagen molecules into fibrils and of potential restrictions on the growth of the collagen fibrils is discussed.

Collagen type VII α1 chain: A promising prognostic and immune infiltration biomarker of pancreatic cancer.

Pancreatic cancer (PC) is a stubborn malignancy with high lethality and a low 5-year overall survival (OS) rate. Collagen type VII α1 chain (COL7A1), a major component of the extracellular matrix, serves important roles in numerous physiological processes and various illnesses. COL7A1 protein acts as an anchoring fibril between the external epithelial cells and the underlying stroma, and mutation of COL7A1 could cause recessive dystrophic epidermolysis bullosa. Raw data for PC were acquired from The Cancer Genome Atlas and the Gene Expression Omnibus database, and raw data for the normal pancreas were obtained from the Genotype-Tissue Expression database. COL7A1 mRNA expression in PC tissues was compared with that in either paired (GSE15471 dataset) or unpaired (all other data) normal pancreas tissues. The association between COL7A1 mRNA expression and clinicopathological factors was assessed using logistic regression analysis. Cox analysis and Kaplan-Meier analysis were used to evaluate the role of COL7A1 mRNA expression in prognosis and nomograms were constructed. Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes analysis, Gene Set Enrichment Analysis (GSEA) and single-sample GSEA (ssGSEA) were performed to evaluate the relevant functions of COL7A1 and correlation with immune cell infiltration. Furthermore, reverse transcription-quantitative PCR was used to assess the mRNA expression levels of COL7A1 in PC. The present study demonstrated that COL7A1 mRNA expression was higher in PC tissues compared with in normal pancreas tissues. The Kaplan-Meier survival analysis indicated that patients with PC with high COL7A1 mRNA expression had shorter overall survival (OS), disease-specific survival (DSS) and progression-free interval (PFI) times compared with patients with PC with low COL7A1 mRNA expression. Multivariate analysis demonstrated that COL7A1 mRNA expression was an independent risk factor for OS, DSS and PFI. Nomogram and calibration plots were constructed to predict the prognosis of patients with PC. GSEA demonstrated that high mRNA expression levels of COL7A1 were associated with multiple cancer-related pathways. ssGSEA analysis indicated that COL7A1 expression was positively associated with natural killer CD56bright cells and T helper (Th)2 cells, and negatively associated with Th17 cells and eosinophils. The results of the present study suggested that COL7A1 could be an independent biomarker and an influential moderator of immune infiltration in PC.

Valorization of emperor fish (Lethrinus lentjan) skin for collagen isolation: effect of acetic acid ratio and extraction time

About 30% of all the proteins in an animal’s body are found in the extracellular matrix, the major consisting of collagen. Industries that process emperor fish (Lethrinus lentjan) produce fish skin that can be utilized to produce collagen sustainably. The objective of this research is to determine the effect of various ratios acetic acid to fish skin and extraction times on the characteristics of collagen. Collagen from the skin of emperor fish was extracted and treated first. For the pretreatment, the skin was immersed in 0.1 M NaOH tenfold (w/v) and replaced after 2 hours for 24 hours at 4 °C. The soaking solution’s proteins, amino acids, and lipid content were all examined. A pre-treated sample was extracted in 0.5 M acetic acid for 24, 36, and 48 hours at 4°C in ratios of 1:10, 1:20, and 1:30. (w:v). The optimum treatment involved extracting for 48 hours at 1:30 (w/v) in acetic acid. The extracted collagen has a yield of 7.70±35% and a whiteness value of 66.76±0.2. The primary amino acids were glycine, proline, and alanine, according to the peptide patterns of the collagen from the skin of emperor fish, which showed α1 and α2 chains with molecular weights of 150-177 kDa. Additionally, this collagen was type 1, and its FTIR spectra and protein pattern were comparable.

Extraction And Characterization Of Pig Skin Gelatin Compared To Commercial Porcine Gelatin

A study was conducted to extract gelatin from pig skin and to evaluate and compare its physicochemical properties with those of commercial porcine gelatin. Whitish yellow-colored gelatin powder was extracted from pig skin through acetic acid pre-treatment, heating, filltration and drying steps. The average yield of pig skin gelatin (PSG) was 5.98 % (w/w). The protein, moisture, fat and ash content of PSG were 90.24, 8.13, 0.60 and 0. 56 %, respectively. The gel (6.67%) prepared from PSG showed a transmittance of 24.71 % and a pH of 6.45. The electrophoretic pattern of the gelatin samples showed the presence of both α1 and α2 chains with the highest molecular weight band observed at around ~ 200 kDa. The L*, a*, and b* values of PSG were recorded as 79.28, 0.58 and 5.79, respectively. Compared to commercial porcine gelatin, PSG had lower hydroxyproline content but a higher pH (p < 0.05) value. Our findings suggest that good quality gelatin with optimal properties can be extracted from low-value pig skin which can provide a suitable alternative to traditional gelatin derived from pork bones or beef bones and skin.

The Study of Type I Collagen by Immunoblotting in Samples of Bone-Plastic Biomaterials

The type I collagen was studied in samples of two types of osteoplastic materials produced in the Biotech Research Institute of the Samara State Medical University using immunoblotting. The demineralized samples used in the work were compact bone powder and crushed material of human cancellous bone tissue. Collagen and its polypeptides were separated in a 5% polyacrylamide gel with 3.6 M urea according to the method of Hayashi and Nagai (1979). The advantage of the method is the separation under these conditions of type I and III collagen, as well as the α1(I) and α2(I) chains of type I collagen. Immunoblotting was carried out by diffusion method according to the method of Towbin et al. (1979) using nitrocellulose membranes (Santa Cruz, USA). Primary goat polyclonal antibodies to denatured collagen, 1:500 dilution (Millipore) were used. Peroxidase-conjugated secondary antibodies (mouse vs. goat), 1:80000 dilution (Sigma) were used also. It has been established that the bulk of the compact bone protein is localized between the α1- and α2-fractions of collagen. In samples of cancellous bone tissue, a molecular reduction of the protein is noted. Protein macromolecules with a gradually decreasing molecular weight and low molecular weight polypeptides migrating in the gel with a wide front up to the indicator line are detected. Due to the low specificity of osteoblast integrins in regenerating bone tissue, collagen polypeptides, as well as protein molecules retained in implants, can act as inducers of synthetic processes occurring in osteoblast nuclei. Protein fragmentation products in the implant can act as signaling molecules that trigger cascades of enzymatic reactions and intracellular signaling pathways.

Type IV collagen α5 chain promotes luminal breast cancer progression through c-Myc-driven glycolysis.

Cancer cell metabolism reprogramming is one of the hallmarks of cancer. Cancer cells preferentially utilize aerobic glycolysis, which is regulated by activated oncogenes and the tumor microenvironment. Extracellular matrix (ECM) in the tumor microenvironment, including the basement membranes (BMs), is dynamically remodeled. However, whether and how ECM regulates tumor glycolysis is largely unknown. We show that type IV collagens, components of BMs essential for the tissue integrity and proper function, are differentially expressed in breast cancer subtypes that α5 chain (α5(IV)) is preferentially expressed in the luminal-type breast cancer and is regulated by estrogen receptor-α. α5(IV) is indispensable for luminal breast cancer development. Ablation of α5(IV) significantly reduces the growth of luminal-type breast cancer cells and impedes the development of luminal-type breast cancer. Impaired cell growth and tumor development capability of α5(IV)-ablated luminal breast cancer cells is attributed to the reduced expression of glucose transporter and glycolytic enzymes and impaired glycolysis in luminal breast cancer cells. Non-integrin collagen receptor discoidin domain receptor-1 (DDR1) expression and p38 mitogen-activated protein kinase activation are attenuated in α5(IV)-ablated luminal breast cancer cells, resulting in reduced c-Myc oncogene expression and phosphorylation. Ectopic expression of constitutively active DDR1 or c-Myc restores the expression of glucose transporter and glycolytic enzymes, and thereafter restores aerobic glycolysis, cell proliferation, and tumor growth of luminal breast cancer. Thus, type IV collagen α5 chain is a luminal-type breast cancer-specific microenvironmental regulator modulating cancer cell metabolism.

Proteomic Analysis of Hepatic Fibrosis in Human Immunodeficiency Virus-Associated Nonalcoholic Fatty Liver Disease Demonstrates Up-regulation of Immune Response and Tissue Repair Pathways.

Human immunodeficiency virus (HIV)-associated nonalcoholic fatty liver disease (NAFLD) is characterized by a high prevalence of hepatic fibrosis as a strong clinical predictor of all-cause and liver-specific mortality risk. We leveraged data from an earlier clinical trial to define the circulating proteomic signature of hepatic fibrosis in HIV-associated NAFLD. A total of 183 plasma proteins within 2 high-multiplex panels were quantified at baseline and at 12 months (Olink Cardiovascular III; Immuno-Oncology). Twenty proteins were up-regulated at baseline among participants with fibrosis stages 2-3 versus 0-1. Proteins most differentially expressed included matrix metalloproteinase 2 (P < .001), insulin-like growth factor-binding protein 7 (P = .001), and collagen α1(I) chain (P = .001). Proteins were enriched within pathways including response to tumor necrosis factor and aminopeptidase activity. Key proteins correlated directly with visceral adiposity and glucose intolerance and inversely with CD4+ T-cell count. Within the placebo-treated arm, 11 proteins differentially increased among individuals with hepatic fibrosis progression over a 12-month period (P < .05). Among individuals with HIV-associated NAFLD, hepatic fibrosis was associated with a distinct proteomic signature involving up-regulation of tissue repair and immune response pathways. These findings enhance our understanding of potential mechanisms and biomarkers of hepatic fibrosis in HIV.

PPAR δ Agonism Ameliorates Renal Fibrosis in an Alport Syndrome Mouse Model.

Alport syndrome is a genetic kidney disease caused by mutation in any of the COL4A3, COL4A4 or COL4A5 genes encoding the type IV collagen α3, α4, and α5 chains. Defects of type IV collagen α3α4α5 cause glomerular basement membrane abnormalities and lead to defects in glomerular filtration and end stage kidney disease. Treatment with angiotensin converting enzyme inhibitors (ACEi) dramatically slows disease progression but does not stop progression to renal failure. Therefore, novel therapeutic options with different modes of action from ACEi are needed. Peroxisome proliferator-activated receptor (PPAR) δ agonists have shown renoprotective effects in several acute kidney injury mouse models. In the present study, we investigated the effects of a potent and selective PPARδ agonist, REN001 (formerly HPP593), in a mouse model of Alport syndrome. We administered REN001 from the early stages to the late stages of disease via once daily intraperitoneal injections. REN001 treatment halved proteinuria at the late stages of disease in Col4a3-/- mice. Blood urea nitrogen levels were also decreased, and histological and molecular analyses showed that REN001 ameliorated renal inflammation and fibrosis. These results indicate that REN001 slows kidney disease progression in Alport mice. REN001 has a different mechanism of action from ACEi, so we therefore hypothesize that combining the two treatments may show additive effects to attenuate renal injury and slow progression to renal failure.

Aging Fibroblasts Adversely Affect Extracellular Matrix Formation via the Senescent Humoral Factor Ependymin-Related Protein 1

Skin senescence is characterized by a decrease in extracellular matrix and the accumulation of senescent fibroblasts in the dermis, and their secretion of humoral factors. Ependymin-related protein 1 (EPDR1) is involved in abnormal fibroblast metabolism and collagen deposition, however, its relation to skin aging is unclear. We investigated whether and how EPDR1 is involved in age-related dermal deterioration. When young dermal fibroblasts and senescent cells were co-cultured in a semipermeable membrane separation system, the young fibroblasts showed decreased gene expression of collagen type I α1 chain (COL1A1) and elastin, and increased expression of matrix metalloproteinase (MMP)1 and MMP3. Senescence marker expression and EPDR1 production were increased in the culture medium of senescent cells. Treatment of young fibroblasts with recombinant EPDR1, enhanced matrix-related gene expression and suppressed COL1A1 expression, whereas EPDR1 knockdown had the opposite effects. EPDR1 gene and protein expression were increased in aged skin, compared to young skin. These results suggest that senescent cells affect nearby fibroblasts, in part through EPDR1 secretion, and exert negative effects on matrix production in the dermis. These results may lead to the discovery of potential candidate targets in the development of skin anti-aging therapies.

Identification of allergenic epitopes destroyed by two processing technologies of glycinin A2 from soybean.

Glycinin is one of the most highly allergenic proteins in soybeans, and G2 is one of the five allergenic subunits of glycinin. Compared with the alkaline chain, the acidic chain A2 of the G2 subunit has strong allergenicity. However, the precise epitopes of A2 and the epitopes destroyed during processing are still unknown. In the present study, preparation of two specific antibodies damaged by processing and phage display techniques were applied to locate the antigenic epitopes of glycinin A2 polypeptide chains disrupted by two processing techniques (thermal processing and ultra-high pressure combined thermal processing). Bioinformatics methods were used to predict the possible epitopes of the A2 chain. The A2 chain and its overlapping segments were introduced into T7 phages and expressed on phage shell by phage display. An indirect enzyme-linked immunosorbent assay was used to screen for antigenic epitopes that had been disrupted by the two processing technologies. The results showed that the dominant antigenic region disrupted by processing was located mainly in the A2-3-B fragment. The reacting experiment with the serum of allergic patients showed that the A2-3-B fragment protein was not only an antigenic region, but also an allergenic region. The two processing technologies destroyed the allergenic epitopes of A2 chain, thereby reducing the allergenicity of protein. The amino acids where the dominant allergenic region disrupted by processing was located were: 233 AIVTVKGGLRVTAPAMRKPQQEEDDDDEEEQPQCVE268 . Precise epitopes of the acidic chain A2 in glycinin were identified and epitopes destroyed in two common processing methods were also obtained. The application products of rapid detection of de-allergenicity effect of processed food can be developed according to the location of processed destruction allergenic region, which is of great significance with respect to preventing the occurrence of soybean allergenic diseases. © 2022 Society of Chemical Industry.

The synergistic effect of physicochemical in vitro microenvironment modulators in human bone marrow stem cell cultures

Modern bioengineering utilises biomimetic cell culture approaches to control cell fate during in vitro expansion. In this spirit, herein we assessed the influence of bidirectional surface topography, substrate rigidity, collagen type I coating and macromolecular crowding (MMC) in human bone marrow stem cell cultures. In the absence of MMC, surface topography was a strong modulator of cell morphology. MMC significantly increased extracellular matrix deposition, albeit in a globular manner, independently of the surface topography, substrate rigidity and collagen type I coating. Collagen type I coating significantly increased cell metabolic activity and none of the assessed parameters affected cell viability. At day 14, in the absence of MMC, none of the assessed genes was affected by surface topography, substrate rigidity and collagen type I coating, whilst in the presence of MMC, in general, collagen type I α1 chain, tenascin C, osteonectin, bone sialoprotein, aggrecan, cartilage oligomeric protein and runt-related transcription factor were downregulated. Interestingly, in the presence of the MMC, the 1000 kPa grooved substrate without collagen type I coating upregulated aggrecan, cartilage oligomeric protein, scleraxis homolog A, tenomodulin and thrombospondin 4, indicative of tenogenic differentiation. This study further supports the notion for multifactorial bioengineering to control cell fate in culture.

High-efficiency secretory expression and characterization of the recombinant type III human-like collagen in Pichia pastoris

Collagen, the highest content protein in the body, has irreplaceable biological functions, and it is widespread concerned in food, beauty, and medicine with great market demand. The gene encoding the recombinant type III human-like collagen α1 chain fragment was integrated into P. pastoris genome after partial amino acids were substituted. Combined with promoter engineering and high-density fermentation technology, soluble secretory expression with the highest yield of 1.05 g L−1 was achieved using two-stage feeding method, and the purity could reach 96% after affinity purification. The determination of N/C-terminal protein sequence were consistent with the theoretical expectation and showed the characteristics of Gly-X-Y repeated short peptide sequence. In amino acid analysis, glycine shared 27.02% and proline 23.92%, which were in accordance with the characteristics of collagen. Ultraviolet spectrum combined with Fourier transform infrared spectroscopy as well as mass spectrometry demonstrated that the target product conformed to the characteristics of collagen spectrums and existed as homologous dimer and trimer in the broth. This work provided a sustainable and economically viable source of the recombinant type III human-like collagen.Graphical

Anti-laminin 332 antibody detection using biochip immunofluorescence microscopy in a real-life cohort of Italian patients with mucous membrane pemphigoid.

Mucous membrane pemphigoid (MMP) with anti-laminin 332 autoantibodies may be associated with malignancies, however, current serological assays have considerable limitations. At present, no commercial test for anti-laminin 332 antibodies is available, restricting the diagnosis to specialized laboratories worldwide. Biochip immunofluorescence microscopy has shown promising results in selected cohorts of laminin 332-MMP patients. Objectives: To detect anti-laminin 332 antibodies by biochip immunofluorescence microscopy in a real-life cohort of MMP patients and compare the results with those from traditional immunoblotting. Sera were obtained from 31 patients with MMP, 28 with bullous pemphigoid, five with pemphigus vulgaris, five with paraneoplastic pemphigus, five with linear IgA bullous dermatosis, and 10 controls, and analysed by biochip immunofluorescence using human cells expressing laminin 332. Immunoblotting was performed using purified laminin 332. MMP involved the oral mucosa in 65%, ocular mucosa in 9%, oral and ocular mucosae extensively in 13% as well as other mucosae in 13% of patients. Concomitant cutaneous involvement was reported in 35% of patients. Three MMP patients had an underlying malignancy. Anti-laminin 332 antibodies were detected in 2/31 (6%) cases by both methods. Based on immunoblotting, both laminin 332-positive sera reacted with α3 chain (in one case also with β3 chain). Both patients with anti-laminin 332 antibodies had extensive mucosal involvement and only one had cancer. Anti-laminin 332 antibodies were not detected in control groups. Biochip immunofluorescence is an appropriate technique to detect anti-laminin 332 antibodies which should be tested in patients with MMP.

Molecular Characteristics and Promoter Analysis of Porcine COL1A1.

COL1A1 encodes the type I collagen α1 chain, which shows the highest abundance among members of the collagen family and is widely expressed in different mammalian cells and tissues. However, its molecular characteristics are not completely elucidated. In this study, the molecular profiles of COL1A1 and characteristics of the COL1A1 protein were investigated using a promoter activity assay and multiple bioinformatics tools. The results showed that the 5' flanking region of porcine COL1A1 contained two CpG islands, five core promoter sequences, and twenty-six transcription factor-binding sites. In the luciferase assay, the upstream 294 bp region of the initiation codon of COL1A1 showed the highest activity, confirming that this section is the core region of the porcine COL1A1 promoter. Bioinformatic analysis revealed that COL1A1 is a negatively charged, hydrophilic secreted protein. It does not contain a transmembrane domain and is highly conserved in humans, mice, sheep, and pigs. Protein interaction analysis demonstrated that the interaction coefficient of COL1A1 with COL1A2, COL3A1, ITGB1, and ITGA2 was greater than 0.9, suggesting that this protein plays a crucial role in collagen structure formation and cell adhesion. These results provide a theoretical basis for further investigation of the functions of porcine COL1A1.