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    Lari Häkkinen

    Tissue and cell type-specific cell-free extracellular matrices generated by various decellularization protocols can be important tools to study cell interactions with their distinct extracellular niche. Our recent findings have shown that... more
    Tissue and cell type-specific cell-free extracellular matrices generated by various decellularization protocols can be important tools to study cell interactions with their distinct extracellular niche. Our recent findings have shown that the widely used NH4OH/Triton X-100/DNase decellularization method is not able to completely remove cytoskeletal proteins from long-term three-dimensional human gingival fibroblast cultures. Therefore, we developed a novel decellularization protocol that involves sequential incubation of the cultures with latrunculin B, an actin destabilizing agent, deoxycholate, a mild detergent, and DNase. This protocol efficiently removes cytoskeletal proteins, including actin and beta-tubulin, and DNA from the cultures, which could interfere with the cell-matrix interactions of cells seeded on the decellularized matrices.
    Standard cell cultures are performed in aqueous media with a low macromolecule concentration compared to tissue microenvironment. In macromolecular crowding (MMC) experiments, synthetic polymeric crowders are added into cell culture media... more
    Standard cell cultures are performed in aqueous media with a low macromolecule concentration compared to tissue microenvironment. In macromolecular crowding (MMC) experiments, synthetic polymeric crowders are added into cell culture media to better mimic macromolecule concentrations found in vivo. However, their effect on cultured cells is incompletely understood and appears context-dependent. Here we show using human gingival fibroblasts, a cell type associated with fast and scarless wound healing, that MMC (standard medium supplemented with Ficoll 70/400) potently modulates fibroblast phenotype and extracellular matrix (ECM) composition compared to standard culture media (nMMC) over time. MMC significantly reduced cell numbers, but increased accumulation of collagen I, cellular fibronectin, and tenascin C, while suppressing level of SPARC (Secreted Protein Acidic and Cysteine Rich). Out of the 75 wound healing and ECM related genes studied, MMC significantly modulated expression o...
    <p>Confluent cultures of gingival fibroblasts (GFBL-DC) were treated with Gap27 or control peptide (150 μM) for 1, 2, 6, and 24 h. Cell lysates were analyzed for protein levels of total SMAD3 and phosphorylated SMAD3 (p-SMAD3) (A),... more
    <p>Confluent cultures of gingival fibroblasts (GFBL-DC) were treated with Gap27 or control peptide (150 μM) for 1, 2, 6, and 24 h. Cell lysates were analyzed for protein levels of total SMAD3 and phosphorylated SMAD3 (p-SMAD3) (A), total p38 and phosphorylated p38 (p-p38) (C), total ERK1/2 and phosphorylated ERK1/2 (p-ERK1/2) (E), total GSK3α/β and phosphorylated GSK3α/β (p-GSK3α/β) (G), and total β-Catenin, phosphorylated β-Catenin (p-β-Catenin) and non-p-β-Catenin (I). (B, D, F, H and J) Quantitation of the phosphorylated or non-phosphorylated signaling molecules relative to their total levels at time 0 (control samples), and at 1, 2, 6 and 24 h after Gap27 treatment. Sample loading was normalized for β-Tubulin levels. Results from one experiment are shown.</p
    In periodontal disease (PD), bacterial biofilms cause gingival inflammation, leading to bone loss. In healthy individuals, αvβ6 integrin in junctional epithelium maintains anti-inflammatory transforming growth factor-β1 (TGF-β1)... more
    In periodontal disease (PD), bacterial biofilms cause gingival inflammation, leading to bone loss. In healthy individuals, αvβ6 integrin in junctional epithelium maintains anti-inflammatory transforming growth factor-β1 (TGF-β1) signaling, whereas its expression is lost in individuals with PD. Bacterial biofilms suppress β6 integrin expression in cultured gingival epithelial cells (GECs) by attenuating TGF-β1 signaling, leading to an enhanced pro-inflammatory response. In the present study, we show that GEC exposure to biofilms induced activation of mitogen-activated protein kinases and epidermal growth factor receptor (EGFR). Inhibition of EGFR and ERK stunted both the biofilm-induced ITGB6 suppression and IL1B stimulation. Furthermore, biofilm induced the expression of endogenous EGFR ligands that suppressed ITGB6 and stimulated IL1B expression, indicating that the effects of the biofilm were mediated by autocrine EGFR signaling. Biofilm and EGFR ligands induced inhibitory phospho...
    Compared to skin, wound healing in oral mucosa is faster and produces less scarring, but the mechanisms involved are incompletely understood. Studies in mice have linked high expression of CD26 to a profibrotic fibroblast phenotype, but... more
    Compared to skin, wound healing in oral mucosa is faster and produces less scarring, but the mechanisms involved are incompletely understood. Studies in mice have linked high expression of CD26 to a profibrotic fibroblast phenotype, but this has not been tested in models more relevant for humans. We hypothesized that CD26 is highly expressed by human skin fibroblasts (SFBLs), and this associates with a profibrotic phenotype distinct from gingival fibroblasts (GFBLs). We compared CD26 expression in human gingiva and skin and in gingival and hypertrophic-like scar-forming skin wound healing in a pig model, and used three-dimensional cultures of human GFBLs and SFBLs. In both humans and pigs, nonwounded skin contained abundantly CD26-positive fibroblasts, whereas in gingiva they were rare. During skin wound healing, CD26-positive cells accumulated over time and persisted in forming hypertrophic-like scars, whereas few CD26-positive cells were present in the regenerated gingival wounds....
    Microvesicles (MVs) are extracellular vesicles secreted by various cell types that are involved in intercellular communication. We hypothesized that in human periodontal disease, the pocket epithelium releases MVs, which then modulate... more
    Microvesicles (MVs) are extracellular vesicles secreted by various cell types that are involved in intercellular communication. We hypothesized that in human periodontal disease, the pocket epithelium releases MVs, which then modulate gene expression in the underlying fibroblasts to control periodontal inflammation. MVs were isolated from culture medium of gingival epithelial cells (GECs) treated with oral bacterial biofilm extract or left untreated. Biofilm treatment significantly increased MV release from the GECs. Mass spectrometry of GEC-MVs identified a total of 2,173 proteins, of which about 80% were detected in MVs from both control and biofilm-treated GECs. Among 80 signature genes of human gingival fibroblasts, 20 were significantly regulated (P < 0.05) by MVs from control and biofilm-treated GECs in a similar manner. Matrix metalloproteinase 1 and 3 and interleukin 6 and 8 showed the strongest regulation at the mRNA and protein levels. Several cellular signaling pathway...
    Extracellular vesicles released from cells regulate many normal and pathological conditions. Little is known about the role of epidermal keratinocyte microvesicles (KC-MVs) in epithelial-stromal interaction that is essential for wound... more
    Extracellular vesicles released from cells regulate many normal and pathological conditions. Little is known about the role of epidermal keratinocyte microvesicles (KC-MVs) in epithelial-stromal interaction that is essential for wound healing. We investigated, therefore, whether MV-like structures are present in human wounds and whether they affect wound healing-associated gene expression in dermal fibroblasts. In human wounds, MV-like vesicles were observed during active epithelial migration and early granulation tissue formation. When KC-MVs derived from keratinocyte-like cells (HaCaT) were added to fibroblast cultures, expression of 21 genes was significantly regulated (P<0.05) out of 80 genes investigated, including matrix metalloproteinase-1 and -3, interleukin-6 and -8, and genes associated with transforming growth factor-β signaling. Similar changes were observed at the protein level. MVs from normal epidermal keratinocytes showed similar response to HaCaT cells. KC-MVs ac...
    We examined the expression of laminin-5 and its integrin receptors during reepithelialization of human wounds. We used suction blisters of skin as a model of keratinocyte migration on a basement membrane matrix and mucosal full-thickness... more
    We examined the expression of laminin-5 and its integrin receptors during reepithelialization of human wounds. We used suction blisters of skin as a model of keratinocyte migration on a basement membrane matrix and mucosal full-thickness wounds as a model in which keratinocytes migrate in a provisional matrix. An animal model, in which human epidermal keratinocytes were injected into the back of athymic mice, was used to follow the deposition of the basement membrane components. In 4-day-old blisters, about 20–50 cells at the leading edge of the migrating tongue showed cytoplasmic laminin-5 immunostaining. Laminin-5 mRNA was detected in 15–30 cells at the leading edge of the migrating epidermis. α3β1and α6β4integrins were found in membrane projections of the migrating basal cells and also in suprabasal cell layers, suggesting their combined role in binding laminin-5. In mucosal wounds, laminin-5 was the only basement membrane zone component that was deposited between the clot and th...
    Tenascin-C (TN-C) and its isoforms are multidomain extracellular matrix (ECM) proteins that are believed to be involved in the regulation of stromal–epithelial interactions. Some of the interactions between TN-C and cells are mediated by... more
    Tenascin-C (TN-C) and its isoforms are multidomain extracellular matrix (ECM) proteins that are believed to be involved in the regulation of stromal–epithelial interactions. Some of the interactions between TN-C and cells are mediated by integrins. In this study we analyzed the expression of TN-C and its large molecular weight splice isoform (TN-CL) and the putative TN-C-binding α9 and αvβ6 integrins during human wound repair. In 3-day-old oral mucosal wounds, immunoreactivity for α9 integrin localized abundantly at the migrating basal wound epithelial cells. TN-C and TN-CL were localized in the matrix between and underneath α9-expressing epithelial cells. In parallel with gradual downregulation of α9 integrin immunoreactivity in 7-day and older wounds, the expression of αvβ6 integrin was temporarily induced. Integrin αvβ6 co-localized in the same area as TN-C and TN-CL immunoreactivity at the cell–cell contacts of the basal and suprabasal cell layers of the wound epithelium. During...
    Tooth enamel has the highest degree of biomineralization of all vertebrate hard tissues. During the secretory stage of enamel formation, ameloblasts deposit an extracellular matrix that is in direct contact with ameloblast plasma... more
    Tooth enamel has the highest degree of biomineralization of all vertebrate hard tissues. During the secretory stage of enamel formation, ameloblasts deposit an extracellular matrix that is in direct contact with ameloblast plasma membrane. Although it is known that integrins mediate cell-matrix adhesion and regulate cell signaling in most cell types, the receptors that regulate ameloblast adhesion and matrix production are not well characterized. Thus, we hypothesized that αvβ6 integrin is expressed in ameloblasts where it regulates biomineralization of enamel. Human and mouse ameloblasts were found to express both β6 integrin mRNA and protein. The maxillary incisors of Itgb6−/− mice lacked yellow pigment and their mandibular incisors appeared chalky and rounded. Molars of Itgb6−/− mice showed signs of reduced mineralization and severe attrition. The mineral-to-protein ratio in the incisors was significantly reduced in Itgb6−/− enamel, mimicking hypomineralized amelogenesis imperfec...
    Soft tissue calcification occurs in many parts of the body, including the gingival tissue. Epithelial cell-derived MVs can control many functions in fibroblasts but their role in regulating mineralization has not been explored. We... more
    Soft tissue calcification occurs in many parts of the body, including the gingival tissue. Epithelial cell-derived MVs can control many functions in fibroblasts but their role in regulating mineralization has not been explored. We hypothesized that microvesicles (MVs) derived from gingival epithelial cells could regulate calcification of gingival fibroblast cultures in osteogenic environment. Human gingival fibroblasts (HGFs) were cultured in osteogenic differentiation medium with or without human gingival epithelial cell-derived MV stimulation. Mineralization of the cultures, localization of the MVs and mineral deposits in the HGF cultures were assessed. Gene expression changes associated with MV exposure were analyzed using gene expression profiling and real-time qPCR. Within a week of exposure, epithelial MVs stimulated robust mineralization of HGF cultures that was further enhanced by four weeks. The MVs taken up by the HGF's did not calcify themselves but induced intracellu...
    BACKGROUND Decontamination of biofilm-infected rough implant surfaces is challenging. Platelet rich blood products have been shown to have anti-microbial properties against periodontal pathogens. Our aim was to investigate the effect of a... more
    BACKGROUND Decontamination of biofilm-infected rough implant surfaces is challenging. Platelet rich blood products have been shown to have anti-microbial properties against periodontal pathogens. Our aim was to investigate the effect of a potential biological implant surface disinfectant, leukocyte-platelet rich fibrin (L-PRF), on a mature oral multispecies biofilm on a rough titanium surface. METHODS SLA titanium disks were inoculated with subgingival dental plaque and cultured anaerobically for 21 days. The L-PRF membranes were collected from 12 donors in three trials (four donors in each trial). The disks were rinsed with 0.9% NaCl and exposed to the cell-rich portion of the L-PRF membranes for 48 hours followed by scanning electron microscope (SEM) analysis immediately or after rinsing with 0.9% NaCl prior to fixation. The presence of platelet factor-4 in the rinse samples was analyzed by Western blotting. Remaining bacteria were quantified from SEM images of the implant surfaces and their numbers statistically compared. RESULTS The L-PRF-treated samples without rinsing displayed numerous cells with multiple pseudopodia in immediate contact with bacteria that appeared perforated and increased in size. The cells were identified as platelets based on morphological criteria and by positive reaction for platelet factor-4 by Western blotting. After post-treatment rinsing, the L-PRF-treated disks displayed a significant reduction in bacterial counts (in average 92% reduction). CONCLUSION Application of L-PRF significantly reduced bacterial counts on contaminated SLA titanium surface, most likely through anti-microbial action by platelets. This article is protected by copyright. All rights reserved.
    BACKGROUND Leukocyte- and platelet-rich fibrin (L-PRF) is a blood-derived biomaterial rich in leukocytes and platelets embedded in a high-density fibrin network that can be compressed into a membrane and used in surgical applications to... more
    BACKGROUND Leukocyte- and platelet-rich fibrin (L-PRF) is a blood-derived biomaterial rich in leukocytes and platelets embedded in a high-density fibrin network that can be compressed into a membrane and used in surgical applications to stimulate tissue regeneration and wound healing, especially in oral cavity. This study aimed to determine the combined effects of the growth factors and cells present in L-PRF on fibroblasts that directly face the L-PRF membranes placed during surgical procedures. METHODS The effect of L-PRF from six donors on the expression of 84 key wound healing genes in normal human gingival fibroblasts was tested by RT-qPCR. RESULTS L-PRF significantly regulated the expression of 33 fibroblast genes (39%), including interleukins, myofibroblast-, extracellular matrix- and angiogenesis-associated genes, and matrix metalloproteinase-1 and -3. L-PRF regulated fibroblast gene expression both time- and dose-dependently, and the effects were mediated by mitogen-activated protein kinases ERK1/2, JNK and p38. L-PRF also stimulated fibroblast wound closure and promoted the ability of fibroblasts to induce endothelial tube formation. L-PRF induced gene expression changes in fibroblast were similar to those observed in early human and pig wounds. CONCLUSIONS This study provides new insights into the biological mechanism by which L-PRF regulates key gingival fibroblast functions important in wound healing.
    Fibroblasts are the most abundant connective tissue cells and play an important role in wound healing. It is possible that faster and scarless wound healing in oral mucosal gingiva relative to skin may relate to the distinct phenotype of... more
    Fibroblasts are the most abundant connective tissue cells and play an important role in wound healing. It is possible that faster and scarless wound healing in oral mucosal gingiva relative to skin may relate to the distinct phenotype of the fibroblasts residing in these tissues. Connexin 43 (Cx43) is the most ubiquitous Cx in skin (SFBLs) and gingival fibroblasts (GFBLs), and assembles into hemichannels (HCs) and gap junctions (GJs) on the cell membrane. We hypothesized that SFBLs and GFBLs display distinct expression or function of Cx43, and that this may partly underlie the different wound healing outcomes in skin and gingiva. Here we show that Cx43 distinctly formed Cx43 GJs and HCs in human skin and gingiva in vivo. However, in SFBLs, in contrast to GFBLs, only a small proportion of total Cx43 assembled into HC plaques. Using an in vivo-like 3D culture model, we further show that the GJ, HC, and channel-independent functions of Cx43 distinctly regulated wound healing-related ge...
    Periodontal diseases manifest by the formation of deep pockets between the gingiva and teeth where multispecies bacterial biofilms flourish, causing inflammation and bone loss. Epithelial cell receptor αvβ6 integrin that regulates... more
    Periodontal diseases manifest by the formation of deep pockets between the gingiva and teeth where multispecies bacterial biofilms flourish, causing inflammation and bone loss. Epithelial cell receptor αvβ6 integrin that regulates inflammation by activating the anti-inflammatory cytokine transforming growth factor-β1, is highly expressed in healthy junctional epithelium that connects the gingiva to the tooth enamel. However, its expression is attenuated in human periodontal disease. Moreover, Itgb6 (-/-) mice display increased periodontal inflammation compared to wild-type mice. We hypothesized that bacterial biofilms present in the periodontal pockets suppress αvβ6 integrin levels in periodontal disease and that this change aggravates inflammation. To this end, we generated three-week-old multi-species oral biofilms in vitro and treated cultured gingival epithelial cells (GECs) with their extracts. The biofilm extracts caused suppression of β6 integrin expression and upregulation o...
    Connective tissues are known to be composed of heterogeneous fibroblast subpopulations. The significance of this heterogeneity in different physiological and pathological conditions is poorly understood. Granulation tissue is formed in... more
    Connective tissues are known to be composed of heterogeneous fibroblast subpopulations. The significance of this heterogeneity in different physiological and pathological conditions is poorly understood. Granulation tissue is formed in connective tissue during wound healing, chronic inflammation, and certain pathological conditions. In this study, heterogeneity of fibroblasts from granulation tissue was investigated by cell-cloning techniques. Granulation-tissue fibroblasts (GTFs) from both chronically inflamed periodontal lesions and healing wound granulation tissue behaved similarly. GTFs showed a more pronounced decrease in proliferative capacity with increasing cumulative population doubling levels (CPDLs) and 30-40% lower cloning efficiency compared with normal gingival fibroblasts (HGFs). Morphologically, cells in GTF cultures were mainly large, whereas HGFs were mainly small in size. Both cell-line types showed heterogeneity in cell morphology. Clones composed of large stellate-like cells predominated in GTF cultures, whereas clones composed of small spindle-shaped or epithelioid cells predominated in HGF cultures. In both cell-line type the proportion of clones composed of large cells increased without increasing CPDL. These findings show that the properties of the fibroblasts changed during their in vitro life spans. The finding that normal connective tissue and granulation tissues contain morphologically distinct fibroblast clones in different proportions suggests that local factors could stimulate local fibroblasts to differentiate into GTFs. Alternatively, local factors could select some fibroblast subpopulations to overgrow the others to form granulation tissue.
    Connexins (C×s) are a family of transmembrane proteins that form hemichannels and gap junctions (GJs) on the cell membranes, and transfer small signaling molecules between the cytoplasm and extracellular space and between connecting... more
    Connexins (C×s) are a family of transmembrane proteins that form hemichannels and gap junctions (GJs) on the cell membranes, and transfer small signaling molecules between the cytoplasm and extracellular space and between connecting cells, respectively. Among C×s, suppressing C×43 expression or function promotes skin wound closure and granulation tissue formation, and may alleviate scarring, but the mechanisms are not well understood. Oral mucosal gingiva is characterized by faster wound closure and scarless wound healing outcome as compared to skin wounds. Therefore, we hypothesized that C×43 function is down regulated during human gingival wound healing, which in fibroblasts promotes expression of genes conducive for fast and scarless wound healing. Cultured gingival fibroblasts expressed C×43 as their major connexin. Immunostaining of unwounded human gingiva showed that C×43 was abundantly present in the epithelium, and in connective tissue formed large C×43 plaques in fibroblast...
    Significance: Regulation of cell adhesions during tissue repair is fundamentally important for cell migration, proliferation, and protein production. All cells interact with extracellular matrix proteins with cell surface integrin... more
    Significance: Regulation of cell adhesions during tissue repair is fundamentally important for cell migration, proliferation, and protein production. All cells interact with extracellular matrix proteins with cell surface integrin receptors that convey signals from the environment into the nucleus, regulating gene expression and cell behavior. Integrins also interact with a variety of other proteins, such as growth factors, their receptors, and proteolytic enzymes. Re-epithelialization and granulation tissue formation are crucially dependent on the temporospatial function of multiple integrins. This review explains how integrins function in wound repair. Recent Advances: Certain integrins can activate latent transforming growth factor beta-1 (TGF-β1) that modulates wound inflammation and granulation tissue formation. Dysregulation of TGF-β1 function is associated with scarring and fibrotic disorders. Therefore, these integrins represent targets for therapeutic intervention in fibros...
    Organotypic cultures have been used to study epithelial cell behavior for many years. The aim of this study was to develop an organotypic culture method that better mimics the three-dimensional morphology of interdigitating rete ridges... more
    Organotypic cultures have been used to study epithelial cell behavior for many years. The aim of this study was to develop an organotypic culture method that better mimics the three-dimensional morphology of interdigitating rete ridges and connective tissue papillae and that also conserves the basement membrane zone (BMZ). Bovine tongue mucosa connective tissue, separated from epithelium after 1 M NaCl incubation, was used as organotypic culture substratum for different human keratinocyte cell lines. Organotypic cultures were characterized by electron and immunofluorescence microscopy for expression of integrin subunits and extracellular matrix components. While spontaneously immortalized mucosal keratinocytes produced highly irregular stratified organotypic cultures, the normal human epidermal keratinocytes (NHEK) demonstrated culture morphology that resembled in vivo epidermis. However, in this model, the histomorphology, expression of differentiation markers involucrin, keratin 1...
    Collagenase-3 (matrix metalloproteinase 13; MMP-13) is a novel matrix metalloproteinase, the expression of which to date has only been detected in human breast carcinoma tissue and osteoarthritic cartilage. Here, we show that MMP-13... more
    Collagenase-3 (matrix metalloproteinase 13; MMP-13) is a novel matrix metalloproteinase, the expression of which to date has only been detected in human breast carcinoma tissue and osteoarthritic cartilage. Here, we show that MMP-13 transcripts are expressed by human HaCaT keratinocytes but not by primary human epidermal keratinocytes. The levels of MMP-13 mRNAs in HaCaT cells were enhanced up to 130- and 45-fold by tumor necrosis factor alpha (TNF-alpha) and transforming growth factor beta (TGF-beta), respectively. The maximal induction of MMP-13 mRNAs by TNF-alpha was noted after a 6-h incubation, whereas with TGF-beta, the maximal stimulation was observed after 24 h. The up-regulation of MMP-13 mRNA abundance by TNF-alpha and TGF-beta was dependent on protein synthesis and was prevented partially by dexamethasone and retinoic acid. Nuclear run-on assays demonstrated activation of MMP-13 gene transcription by TNF-alpha maximally at the 2-h time point and by TGF-beta after 12 h of ...
    A large pool of precursor beta 1-integrin subunits is frequently found intracellularly. During malignant transformation this pool often disappears. Concomitantly, integrin-mediated cell-adhesion functions are disturbed, even though no... more
    A large pool of precursor beta 1-integrin subunits is frequently found intracellularly. During malignant transformation this pool often disappears. Concomitantly, integrin-mediated cell-adhesion functions are disturbed, even though no change in the number of beta 1-integrin receptors on the cell surface can be observed. Here, we have studied the role of an intracellular pre-beta 1-integrin pool by transfecting human MG-63 osteosarcoma cells with plasmid construction producing an antisense RNA for the beta 1-integrin subunit. Stable cell clones expressing beta 1-integrin antisense RNA were shown to have a reduced intracellular pool of pre-beta 1-integrin subunits. In the antisense-transfected cells, the synthesis of the beta 1-integrin chain was reduced by 65% compared with non-transfected or vector-transfected MG-63 cells. The decreased synthesis of the beta 1-integrin chain was associated with accelerated maturation of the beta 1-integrin chain (half-maturation time about 5 h in an...
    The alphavbeta6 integrin is an exclusively epithelial integrin that is highly expressed during fetal development. In adult tissue, alphavbeta6 integrin is expressed during inflammation, carcinogenesis, and in wound healing. We previously... more
    The alphavbeta6 integrin is an exclusively epithelial integrin that is highly expressed during fetal development. In adult tissue, alphavbeta6 integrin is expressed during inflammation, carcinogenesis, and in wound healing. We previously reported that alphavbeta6 integrin is highly expressed in poorly healing human wounds and its over-expression is associated with chronic wounds in a mouse model. The objective of this study was to investigate the role of alphavbeta6 integrin in compromised wound healing induced by hydrocortisone treatment or aging by using young and old mice deficient in or overexpressing the beta6 integrin subunit in the epidermis. Untreated aged beta6 integrin-deficient (beta6-/-) animals showed a significant delay in wound healing when compared to their age-matched controls or younger beta6-/- mice. The most significant delay was observed at the stages where granulation tissue deposition was occurring. Hydrocortisone treatment significantly delayed wound healing ...
    ... J Biol Chem. 1988; 263: 4586-92; Tomakidi P, Fusenig NE, Kohl A, Komposch G : Histomorphological and biochemical differentiation capacity in organotypic co-cultures of primary gingival cells. ... This Poster was submitted on 24.07.99... more
    ... J Biol Chem. 1988; 263: 4586-92; Tomakidi P, Fusenig NE, Kohl A, Komposch G : Histomorphological and biochemical differentiation capacity in organotypic co-cultures of primary gingival cells. ... This Poster was submitted on 24.07.99 by Dr. Christopher Hildebrand. ...
    Transforming growth factor beta (TGF-beta) is a biologically multipotent regulatory protein implicated in functions that include the regulation of cellular growth, differentiation, extracellular matrix formation, and wound healing. It... more
    Transforming growth factor beta (TGF-beta) is a biologically multipotent regulatory protein implicated in functions that include the regulation of cellular growth, differentiation, extracellular matrix formation, and wound healing. It also plays a role in the pathologies of Alzheimer's disease, cancer and autoimmune disorders. TGF-beta modulates gene expression by affecting transcriptional activation and mRNA turnover rate. Steady-state mRNA levels depend on both the transcriptional activity and mRNA half-life. The stability of mRNA can be modified by the binding of trans-acting factors to cis-elements on the message. These can protect the mRNA from cleavage by RNAses, or they may promote mRNA cleavage. Changes in mRNA stability can lead to changes in the proteome and subsequently in cellular metabolism. The SMAD family of proteins has been implicated in the transduction of the TGF-beta signal, where they regulate transcriptional activity. This review attempts to provide new insights into the role played by TGF-beta in the regulation of mRNA turnover.
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