Effects of SET7 on angiotensin II-mediated proliferation and collagen synthesis of myocardial fibroblasts and its mechanisms / 中南大学学报(医学版)

OBJECTIVES@#Silence of SET domain containing lysine methyltransferase 7 (SET7) alleviates myocardial tissue injury caused by ischemia-reperfusion. But the effects of SET7 on angiotensin II (Ang II)-induced myocardial fibroblast proliferation and the collagen synthesis are not clear. The purpose of this study was to explore the effect of SET7 on the proliferation and collagen synthesis of myocardial fibroblasts and its mechanisms.@*METHODS@#Myocardial fibroblasts were isolated and identified by immunofluorescence. Myocardial fibroblasts were randomly divided into 4 groups: a control group (cells were normally cultured), an Ang II group (cells were treated with 100 nmol/L Ang II for 24 h), a siCtrl group (cells were transfected with siRNA control and were then treated with 100 nmol/L Ang II for 24 h), and a siSET7 group (cells were transfected with siRNA SET7 and were then treated with 100 nmol/L Ang II for 24 h). Cell counting kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) assay were used to evaluate cell proliferation. Real-time PCR was used to detect the mRNA levels of SET7, collagen I, collagen III, and α-smooth muscle actin (α-SMA). Western blotting was used to detect the protein expression of SET7, collagen I, collagen III, α-SMA, sonic hedgehog (Shh), ptched1 (Ptch1), and glioma-associated oncogene homolog 1 (Gli1).@*RESULTS@#Fluorescence microscopy showed positive vimentin staining, and myocardial fibroblasts were in good condition. As compared to the control group, the mRNA and protein levels of SET7 in the Ang II group were significantly upregulated; cell proliferation rate and EdU fluorescence intensity in the Ang II group were significantly increased; the mRNA and protein levels of collagen I, collagen III, and α-SMA were significantly upregulated (all @*CONCLUSIONS@#Silence of SET7 gene inhibits Ang II-induced proliferation and collagen synthesis of myocardial fibroblasts. Shh signaling pathway may be involved in this process.

Optimization of unnatural amino acid incorporation in collagen and the cross-linking through thioether bond / 生物工程学报

The source of recombinant collagen is clean, and it has the advantages of flexible sequence design, high yield and high purity, so it has a wide application prospect as biomaterials in tissue engineering and other fields. However, how to promote the cross-linking of recombinant collagen molecules and make them form a more stable spatial structure is the difficulty to be overcome in the design of recombinant collagen nanomaterials. Unnatural amino acid O-(2-bromoethyl)-tyrosine was incorporated into collagen by two-plasmid expression system. The results showed that high-purity collagen incorporated with unnatural amino acid could be obtained by induction with final concentration of 0.5 mmol/L IPTG and 0.06% arabinose at 25 °C for 24 hours. The intermolecular cross-linking through thioether bond was formed between collagen molecule incorporated with unnatural amino acid and collagen molecule with cysteine mutation in pH 9.0 NH4HCO3 buffer, which formed aggregates with the largest molecular size up to 1 micrometre. The results pave the way for the design of recombinant collagen biomaterials.

MLO-Y4 osteocytic cell clones express distinct gene expression patterns characteristic of different stages of osteocyte differentiation / Clones de las células osteocíticas MLO-Y4 tienen diferentes patrones de expresión génica característicos de diferentes estadíos de diferenciación osteocítica

Osteocytes are the most abundant bone cell and are formed when osteoblasts become embedded in the bone matrix. Through changes in gene expression and paracrine effects, osteocytes regulate the number of osteoblasts, bone forming cells, and osteoclasts, bone resorbing cells, which are needed to maintain bone mass. MLO-Y4 is the better characterized osteocytic cell line; however, lacks expression of sclerostin, the product of the SOST gene, which is fundamental for osteocyte function and blocks bone formation. With the objective to isolate MLO-Y4 clones with different gene expression profiles, we performed cultures at very low density of MLO-Y4 cells stably transfected with nuclear green fluorescent protein (MLOnGFP). Cell morphology was visualized under a fluorescence microscope. Once the cells reached 80% confluency, RNA was extracted and quantitative real time PCR was performed. Clones exhibit different sizes and morphology, with some cells showing a spindle-like shape and others with abundant projections and a star-like shape. Gene expression also differed among clones. However, none of the clones examined expressed SOST. We conclude that the MLO-nGFP clones constitute a useful tool to study osteocyte differentiation and the role of osteocytes in the control of bone formation and resorption in vitro. (AU)

Los osteocitos son las células más abundantes del hueso y se forman cuando los osteoblastos se encuentran rodeados de matriz ósea. A través de cambios en la expresión génica y efectos paracrinos, los osteocitos controlan el número de osteoblastos que forman el hueso, y osteoclastos que resorben el hueso, células necesarias para mantener la masa ósea. Las células MLO-Y4 son la línea celular osteocítica más investigada; sin embargo, no expresan esclerostina, el pro esclerostina, el producto del gen SOST que bloquea la formación ósea y es indispensable para la función de los osteocitos. Con el objetivo de aislar clones de las células MLO-Y4 con diferentes perfiles de expresión génica, realizamos cultivos a muy baja densidad de las células transfectadas en forma estable con proteína verde fluorescente nuclear (MLO-nGFP). La morfología celular fue evaluada utilizando un microscopio de fluorescencia. Una vez que las células alcanzaron el 80% de confluencia, el ARN fue extraído y analizado por PCR cuantitativa en tiempo real. Las células de los diferentes clones tienen diferentes tamaños y morfología, algunas células son fusiformes y otras con proyecciones citoplasmáticas abundantes y en forma de estrella. La expresión de los genes también varió en los distintos clones. Sin embargo, ninguno de ellos expresó SOST. En conclusión, los clones de las células MLO-nGFP constituyen una herramienta útil para estudiar la diferenciación de los osteocitos y el rol de estas células en el control de la formación y resorción ósea in vitro. (AU)

Selective intra-dinucleotide interactions and periodicities of bases separated by K sites: a new vision and tool for phylogeny analyses

Direct tests of the random or non-random distribution of nucleotides on genomes have been devised to test the hypothesis of neutral, nearly-neutral or selective evolution. These tests are based on the direct base distribution and are independent of the functional (coding or non-coding) or structural (repeated or unique sequences) properties of the DNA. The first approach described the longitudinal distribution of bases in tandem repeats under the Bose-Einstein statistics. A huge deviation from randomness was found. A second approach was the study of the base distribution within dinucleotides whose bases were separated by 0, 1, 2... K nucleotides. Again an enormous difference from the random distribution was found with significances out of tables and programs. These test values were periodical and included the 16 dinucleotides. For example a high ¨positive¨ (more observed than expected dinucleotides) value, found in dinucleotides whose bases were separated by (3K + 2) sites, was preceded by two smaller ¨negative¨ (less observed than expected dinucleotides) values, whose bases were separated by (3K) or (3K + 1) sites. We examined mtDNAs, prokaryote genomes and some eukaryote chromosomes and found that the significant non-random interactions and periodicities were present up to 1000 or more sites of base separation and in human chromosome 21 until separations of more than 10 millions sites. Each nucleotide has its own significant value of its distance to neutrality; this yields 16 hierarchical significances. A three dimensional table with the number of sites of separation between the bases and the 16 significances (the third dimension is the dinucleotide, individual or taxon involved) gives directly an evolutionary state of the analyzed genome that can be used to obtain phylogenies. An example is provided.

Genes responsible for vaginal extracellular matrix metabolism are modulated by women's reproductive cycle and menopause

Objectives To analyze the expression of genes involved in extracellular matrix (ECM) biogenesis and remodeling in vaginal tissue of women with clinically normal pelvic floor support (defined as controls) according to the phase of menstrual cycle and postmenopausal women with and without pelvic organ prolapse (POP). Materials and Methods This study examined the expression of matrix metalloproteinases (MMPs), their tissue inhibitors (TIMPs), and the Lysyl oxidase (LOX) family genes in the anterior vaginal wall of Caucasian women by real-time RT-PCR. Initially, mRNA expression was assessed in premenopausal controls in the secretory (group 1, n = 10) vs. proliferative (group 2, n = 8) phase of menstrual cycle. In addition, we compared premenopausal controls in the proliferative phase (group 2) vs. postmenopausal controls (group 3, n = 5). Finally, we analyzed postmenopausal controls (group 3) vs. postmenopausal women with advanced POP (group 4, n = 13). Results According to the phase of menstrual cycle, MMP1 was significantly reduced (p = 0.003), whereas the expression of TIMP1 and LOXL4 was significantly up-regulated during proliferative phase (both p < 0.01) when compared to the secretory phase in premenopausal control women. Regarding menopausal status/ageing, all MMPs were down-regulated, while TIMP3, TIMP4 and LOXL2 were significantly up-regulated in postmenopausal control women when compared to premenopausal controls (p = 0.005, p = 0.01 and p < 0.001, correspondingly). TIMP4 and LOXL2 mRNA levels were significantly decreased in postmenopausal POP patients compared to asymptomatic postmenopausal controls (p < 0.01 for both). Conclusions Our results indicate that ovarian cycle and age-related changes influence the expression of genes encoding proteins responsible for ECM metabolism in human vagina. Moreover, POP is associated with alteration in vaginal ECM components after menopause. .

Characterization of human adipose-derived stem cells and expression of chondrogenic genes during induction of cartilage differentiation

OBJECTIVES: Understanding the changes in chondrogenic gene expression that are involved in the differentiation of human adipose-derived stem cells to chondrogenic cells is important prior to using this approach for cartilage repair. The aims of the study were to characterize human adipose-derived stem cells and to examine chondrogenic gene expression after one, two, and three weeks of induction. MATERIALS AND METHODS: Human adipose-derived stem cells at passage 4 were evaluated by flow cytometry to examine the expression of surface markers. These adipose-derived stem cells were tested for adipogenic and osteogenic differentiation capacity. Ribonucleic acid was extracted from the cells for quantitative polymerase chain reaction analysis to determine the expression levels of chondrogenic genes after chondrogenic induction. RESULTS: Human adipose-derived stem cells were strongly positive for the mesenchymal markers CD90, CD73, CD44, CD9, and histocompatibility antigen and successfully differentiated into adipogenic and osteogenic lineages. The human adipose-derived stem cells aggregated and formed a dense matrix after chondrogenic induction. The expression of chondrogenic genes (collagen type II, aggrecan core protein, collagen type XI, COMP, and ELASTIN) was significantly higher after the first week of induction. However, a significantly elevated expression of collagen type X was observed after three weeks of chondrogenic induction. CONCLUSION: Human adipose-derived stem cells retain stem cell characteristics after expansion in culture to passage 4 and serve as a feasible source of cells for cartilage regeneration. Chondrogenesis in human adiposederived stem cells was most prominent after one week of chondrogenic induction.

Displasia espóndilo-epifisiaria asociada a cráneo-sinostosis, cataratas, paladar hendido y retardo mental: Reporte de un caso / Spondylo-epiphyseal dysplasia associated with craniosynostosis, cleft palate and mental retardation: A case report

Las displasias esqueléticas son un grupo muy heterogéneo de trastornos que se caracterizan por una alteración en la organización del tejido óseo, lo que causa una distorsión en su patrón de crecimiento y desarrollo. En 1998, se descibió el caso de cuatro hermanos japoneses, tres varones y una hembra que presentaban una displasia espóndilo-epifisiaria, no descrita anteriormente, asociada con cráneo-sinostosis, cataratas, paladar hendido y retardo mental de diferente grado. Se planteó una probable herencia autosómica recesiva, debido a que las alteraciones afectaban a ambos sexos y los padres eran fenotípicamente sanos, aunque con discreto retardo mental; sin embargo, no fue posible descartar un mosaicismo germinal. El caso que se presenta, trata de un paciente con signos clínicos y radiológicos que coinciden con los previamente descritos. Es producto de padres consanguíneos en la segunda generación, lo cual se sumaría a la presunción ya postulada, de una probable mutación de herencia autosómica recesiva. La presente comunicación, representa el segundo reporte en la literatura, del quinto caso descrito y el segundo grupo familiar con la afección mencionada.

Skeletal dysplasias are a heterogeneous group of disorders characterized by an alteration of the organization of osseous tissue causing a distortion on the growth and development pattern of bones. In 1998, four Japanese sibs were described by the first time, three males and one female who presented a previously undescribed spondylo-epiphyseal dysplasia associated with craniosynostosis, cataracts, cleft palate and different grades of mental retardation. A probable autosomic recessive inheritance was suggested, but a germinal mosaicism could not be discarded. This is a case report of a patient with clinical and radiological findings similar to the ones previously described, born to second degree consanguineous parents. This supports the postulated presumption of a mutation with an autosomic recesive inheritance. The present comunication represents the fifth case reported in the literature and the second familiar group affected.

Estado actual del tratamiento de la hernia inguinal / Study of the treatment of inguinal hernias

The author describes the present status of the treatment of inguinal hernias. The Lichtenstein open tension-free polipropilene mesh repair for inguinal hernias is the procedure of choice for general surgeons, for the treatment of primary or recurrent inguinal hernias, simple or complicated. The laparoscopic repair should be preserved for centers with a great experience in laparoscopic surgery, being the most accurate indications on bilateral hernias, especially if one is recidivated from the anterior route, or if here exists a previous testicular atrophy in one of the sides. The open anterior route con be used by young surgeons with the same results as those obtained by experienced surgeons.

Hipermobilidade articular em pacientes com prolapso da valva mitral: [revisão] / Hipermovilidad articular en pacientes con prolapso de la válvula mitral: [revisión] / Joint hypermobility in patients with mitral valve prolapse: [review]

Estudos sobre hipermobilidade têm despertado grande interesse, nas últimas décadas, por estarem associados a disfunções músculo-esqueléticas, bem como a anormalidades em vários sistemas orgânicos - como, por exemplo, o prolapso da valva mitral. Neste contexto, buscou-se agrupar e atualizar os conhecimentos da relação entre a hipermobilidade articular e o prolapso da valva mitral. Segundo a literatura, estudos mostram que alterações genéticas na composição do colágeno parecem ser a principal causa desta relação.

Estudios sobre hipermovilidad han despertado gran interés en las últimas décadas por su relación con disfunciones musculoesqueléticas, así como con anormalidades en varios sistemas orgánicos - por ejemplo, el prolapso de la válvula mitral. Se buscó agrupar y actualizar, en ese contexto, los conocimientos de la relación entre la hipermovilidad articular y el prolapso de la válvula mitral. De acuerdo con la literatura, estudios indican que alteraciones genéticas en la composición del colágeno parecen ser la principal causa de esta relación.

Studies on hypermobility have aroused great interest in the last decades, as they are associated to musculoskeletal disorders, as well as abnormalities in several organic systems, such as the mitral valve prolapse. Therefore, in this study, data on the association between joint hypermobility and the mitral valve prolapse were investigated and reviewed. Studies in the literature have shown that genetic alterations in the collagen composition seem to be the main cause of this association.

Comparison of Phenotypic Characterization between "Alginate Bead" and "Pellet" Culture Systems as Chondrogenic Differentiation Models for Human Mesenchymal Stem Cells

Chondrogenesis involves the recruitment of mesenchymal cells to differentiate into chondroblasts, and also the cells must synthesize a cartilage-specific extracellular matrix. There were two representative culture systems that promoted the chondrogenic differentiation of human mesenchymal stem cells. These systems were adaptations of the "pellet" culture system, which was originally described as a method for preventing the phenotypic modulation of chondrocytes, and the "alginate bead" culture system, which was used to maintain encapsulated cells at their differentiated phenotype over time, and also it was used to maintain the cells' proteoglycan synthesis at a rate similar to that of primary chondrocytes. We performed test on the differences of phenotypic characterization with the two methods of differentiating human mesenchymal stem cells into chondrocytes. The typical gene for articular cartilage, collagen type II, was more strongly expressed in the "alginate bead" system than in the "pellet" culture system, in addition, specific gene for hypertrophic cartilage, collagen type X, was more rapidly expressed in the "pellet" system than in "alginate bead" culture system. Therefore, the "alginate bead" culture system is a more phenotypical, practical and appropriate system to differentiate human mesenchymal stem cells into articular chondrocytes than the "pellet" culture system.

Utilidad de la cintigrafía en el estudio de las alteraciones hereditarias de la fibra colágena (AHFC) / Utility of bone cintigraphy in the study of hereditary disorders of the connective tissues (HDCT)

Introducción: Las alteraciones genéticas de la Fibra Colagena predisponen a inestabilidad, dolor y osteoartritis de las articulaciones. Ellas producen también fragilidad de otros tejidos.Objetivo: El de demostrar que la Cintigrafía Osea es útil en el diagnóstico de las Alteraciones Hereditarias de la Fibra Colagena (AHFC).Material y Método: Se estudiaron las alteraciones cintigráficas de muñecas, carpos y manos de 22 pacientes adultos con AHFC que fueron diagnosticados clínicamente, usando el criterio de Brighton1 y un criterio elaborado por nosotros. Los comparamos con 22 controles, de edad y sexo similares a los pacientes, que se hicieron un cintigrama oseo por otros motivos.Resultados: Se encontró una diferencia estadísticamente significativa de la positividad de la cintigrafía en las áreas estudiadas en los pacientes, al compararla con los controles (p < 0,05), con una sensibilidad de 95 por ciento y especificidad de 73 por ciento. No había correlación del grado de positividad, con la edad, sexo ni el tipo de AHFC estudiada. Se vio que había positividad cintigráfica tanto en los enfermos con articulaciones laxas como en los con menor grado de laxitud.Conclusiones: Se concluye que la Cintigrafía Ósea es útil en el diagnóstico de las AHFC en el adulto (incluyendo el Síndrome de Hiperlaxitud Articular Benigno (SHAB) y otras formas de Ehlers-Danlos). Se sugiere que tanto la hipermovilidad de las articulaciones, como la fragilidad de los cartílagos articulares, son factores patogénicos importantes en la génesis de dichas alteraciones. Se formula una nueva hipótesis de la importancia de la carencia de ácido fólico durante el embarazo como causa de mutaciones que darían origen a AHFC.

Purification and characterization of recombinant murine endostatin in E. coli

Endostatin, a carboxyl-terminal fragment of collagen XVIII is known as an anti-angiogenic agent, that specifically inhibits the proliferation of endothelial cell and the growth of several primary tumor. We report here the purification and characterization of the recombinant murine endostatin (rmEndostatin) which was expressed in a prokaryotic expression system. This rmEndostatin has similar physiochemical properties of yeast-produced recombinant endostatin, and it also specifically inhibits the proliferation and migration of bovine capillary endothelial cells stimulated by basic fibroblast growth factor. The biological activity of rmEndostatin was also shown by its anti-angiogenic ability on the chorioallantoic membrane of chick embryo in vivo. In this article, we demonstrate the refolding and purification of rmEndostatin, expressed using E. coli system, to a biologically active and soluble form. In addition, these results confirm the activity of endostatin as a potent anti-angiogenic agent. Copyright 2000 Academic Press.

Regulation of type I collagen and interstitial collagenase mRNA expression in human dermal fibroblasts by colchicine and D-penicillamine

Sclerosis is a disease process in which idiopathic hardening occurs in the skin and/or internal organs as a result of the accumulation of type I collagen, induced mainly by transforming growth factor-beta. Colchicine and D-penicillamine are widely used for its treatment. Their effects are known to be due to post-translational down-regulation of type I collagen synthesis, with colchicine also up-regulating interstitial collagenase. To determine whether or not they have any pre-translational effect on type I collagen and MMP-1, and also to observe their effects on the action of TGF-beta, cultured neonatal foreskin fibroblasts were treated with colchicine and D-penicillamine, singly and together. The amount of type I collagen and MMP-1 mRNA were quantitated by Northern blot hybridization. Colchicine suppresses the basal level of type I collagen mRNA but minimally stimulates the mRNA expression of MMP-1, whereas D-penicillamine does not have any significant effects on either. Colchicine was also able to significantly suppress the TGF-beta-induced up-regulation of type I collagen mRNA expression.

Estudio de la asociación alélica entre los polimorfismos de los genes de colágena tipo I (COLIA1 y COLIA2) y daño hepatico de tipo alcohólico / Allelic association study between collagen type I (COLIA1 and COLIA2) polymorphisms and alcohol liver disease

Se desconoce la cantidad de duración del consumo excesivo de alcohol que lleva a la generación del daño hepático. Mientras que en la mayoría de los individuos que abusan del alcohol se desarrolla hígado graso, sólo en una pequeña proporción se genera inexorablemente un daño grave (cirrosis o hepatitis alcohólica). En numerosos estudios se indica la existencia de factores genéticos asociados a la susceptibilidad de desarrollar daño hepático inducido por el alcohol. La producción de la colágena tipo I es particularmente abundante en la cirrosis hepática: por esta razón, los genes que codifican para esta proteína se consideran como "candidatos" importantes en el estudio de la predisposición genética a esta enfermedad. El objetivo de este trabajo es el de analizar los polimorfismos para los genes humanos de colágena tipo I (COLIA1 y COLIA2) en muestras de alcohólicos que presentan o no cirrosis, para probar la hipótesis de que estas variantes pudieran estar asociadas (y probablemente contribuir) a la predisposición a desarrollar el daño hepatico inducido por el consumo excesivo de etanol. Se estudiaron 74 pacientes mexicanos que reconocieron beber 80 g o más de etanol al día durante un lapso de por lo menos 10 años. El diagnóstico o, en su caso, la exclusión de cirrosis, fue establecido por medio de su historia clínica, pruebas de laboratorio, ultrasonido y, en algunos casos, biopsia hepática. Se analizaron los genotipos de 3 diferentes polimorfismos (dos en el gene COLIA1 y uno en el COLIA2), mediante la amplificación de las regiones correspondientes por PCR. No se observaron diferencias en las frecuencias de los alelos y los genotipos entre ambos grupos. Sin embargo, la frecuencia del alelo A2 del sistema polimórfico Rsal/COLIA1 fue mayor en los alcohólicos que en un grupo de sujetos sanos. En conclusión, los polimorfismos analizados no parecen estar asociados a un mayor riesgo o susceptibilidad de desarrollar daño hepático inducido por el alcohol. No se puede descartar que otras variantes no analizadas en este trabajo pudieran estar relacionadas con mutaciones cercanas, las cuales pudieran modificar la biosíntesis o estructura de la colágena tipo I, por medio de la interacción directa o indirecta del alcohol

Hydrocortisone regulates types I and III collagen gene expression and collagen synthesis in human marrow stromal cells

Hematopoiesis is the resultant of the orderly molecular and cellular interactions between progenitor cells and stroma. In vitro studies (Dexter-type cultures) have shown that initiation of hematopoiesis only occurs after establishment of a hydrocortisone-dependent layer of stromal cells. Although the molecular basis for the requirement of hydrocortisone are not well understood, data have shown that synthesis/assembly of extracellular matrix molecules (proteoglycans and fibronectin) is regulated by hydrocortisone. Since interstitial collagens are abundantly expressed in the marrow stroma, we investigated whether hydrocortisone may also modulate the expression of collagen types I and III. For these studies, human bone marrow fibroblast cultures were grown in standard culture medium either in the absence or presence of 10(-7) M hydrocortisone. Under both conditions, bone marrow fibroblasts synthesized collagen types I and III, and expressed the respective genes. However, hydrocortisone produced a decrease in the synthesis of interstitial collagens and also in the relative abundance of pro-alpha 1(I) and pro-alpha 1(III) mRNAs. The results of this study are consistent with the assumption that glucocorticoids regulate the expression of several extracellular matrix molecules in the marrow stroma and thus permit in vitro hematopoiesis to occur

Conceptos actuales sobre colágenas de cartílago y su asociación con enfermedades / Current concepts in cartilage collagens and their association with disease

La principal función de las fibras colágenas del cartílago es la de formar una red estable para contrarrestar la presión por el aumento de volumen generada por los agregados hidratados de proteoglicanos. La mayor parte de la colágena presente en el cartílago es la tipo II aunque tambien hay cantidades pequeñas de los tipos IV, VI, IX, X, XI, y XIV. Para estudiar la patogenia de las mutaciones de las colágenas presentes en el cartílago, se han desarrollado ratones transgénicos. Igualmente, el estudio molecular de estas proteínas han dado un fuerte impulso al conocimiento de la patogenia de algunas enfermedades hereditarias y adquiridas del cartílago. La terapia génica de las enfermedades de la colágena, especialmente las hereditarias del cartílago, ayudará a corregir estas anormalidades. Aquí revisamos todos estos aspectos

Novedades moleculares y clínicas de las colágenas / New molecular and clinical aspects of collagens

La colágena es una de las proteínas más abundantes del organismo. Junto con los otros componentes de la matriz extracelular (glucoproteínas no colagenosas, proteoglicanos, lamininas, fibronectinas, tromboespondinas, enectina y tenascina) promueve la adhesión celular, activa vías de señales intracelulares, y regula las actividades de varios factores de crecimiento y de otas proteínas. Durante los últimos 20 años se han identificado por lo menos 19 tipos de colágenas genéticamente diferentes, codificadas por más de 30 genes. En esta primera parte revisamos algunos aspectos novedosos sobre colágenas fibrilares, las formadoras de láminas, las que forman estructuras tipo abalorio, y las multiplexinas. Cuando fue posible correlacionamos las anormalidades de estas proteínas colagenosas con la enfermedad resultante