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Connective Tissue Growth Factor belongs to the CCN family of proteins. The CCN family presently consists of six members in human also known as: Cyr61 (Cystein rich 61), CTGF (Connective Tissue Growth Factor), Nov (Nephroblastoma Overexpressed gene), WISP-1, 2 and 3 (Wnt-1 Induced Secreted Proteins). The CCN genes encode secreted proteins associated with the Extracellular Matrix (ECM) and cell membrane. CCN proteins are matricellular proteins which are involved in the regulation of various cellular functions including: proliferation, differentiation, survival, adhesion and migration. They are expressed in derivatives of the three embryonic sheets and are implicated in the development of kidney, nervous system, muscle, bone marrow, cartilage and bone. During adulthood, they are implicated in wound healing, bone fracture repair, and pathologies such as: fibrosis, vascular ailments and tumorigenesis.
Full length secreted CCN proteins can show an antiproliferative activity, whereas truncated isoforms are likely to stimulate proliferation and behave as oncogenes. The full length protein consists of four modulesModule I shares partial identity with the N-terminal part of the Insulin-like Growth Factor Binding Proteins (IGFBPs).
Module II includes a stretch of 70amino acid residues – which shares sequence identity with the Von Willebrand Factor Type C repeat (VWC).
Module III contains sequences sharing identity with the Thrombospondin type 1 repeat (TSP1) (WSXCSXXCG), which is thought to be implicated in the binding of sulfated glycoconjugates and to be important for cell adhesion. Module IV, also designated CT, is encoded by exon5. It is the leasts conserved one of the four domains at the level of nucleotide sequence, but it appears to be critical for several of the biological functions attributed to the CCN proteins. Module IV resembles the CT domain of several extracellular protein including, Von Willebrand's factor and mucins. Sequence similarities to heparin-binding motifs are also found within this domain.
Proteolysis of the secreted full-length CCN proteins that has been reported in the case of CCN2 and CCN3 might result in the production of CCN-derived peptides with high affinity for ligands that full-length CNN proteins bind only poorly. Amino-truncated CCN2 isoforms were biologically active whereas no specific biological activity has been attributed to the truncated CCN3. Although the molecular processes underlying the production of these secreted isoforms is presently unknown, it is important to note that proteolysis occur at the same amino acid residues in both CCN2 and CCN3. An elevated expression of CCN2 has also been detected by Northern blotting in human invasive mammary ductal carcinomas, dermatofibromas, pyogenic granuloma, endothelial cells of angiolipomas and angioleiomyomas, and in pancreatic tumors. A study performed with chondrosarcomas representative of various histological grades established that CCN2 expression was closely correlated with increasing levels of malignancy. In agreement with CCN2 playing a role in brain tumor angiogenesis, immunocytochemistry studies indicated that both glioblastoma tumor cells and proliferating endothelial cells stained positive for CCN2. In astrocytomas, CCN2 expression was particularly elevated in high grade tumors, with a marked effect of CCN2 on cell proliferation. Downregulation of CCN2 expression in these cells was associated with a growth arrest at the G1/S transition while over-expression of CCN2 induced a two-fold increase of the number of cells in the G1 phase. Gene profiling analysis allowed to identify a set of about 50 genes whose expression might account for the proliferative activity of CCN2 in these cells. CCN2 was seen in a higher proportion of mononuclear cells of patients with acute lymphoblastic leukemia.

The protein encoded by this gene is a cytokine that acts as a growth and differentiation factor for both B cells and eosinophils. This cytokine is a main regulator of eosinopoiesis, eosinophil maturation and activation. The elevated production of this cytokine is reported to be related to asthma or hypereosinophilic syndromes. The receptor of this cytokine is a heterodimer, whose beta subunit is shared with the receptors for interleukine 3 (IL3) and colony stimulating factor 2 (CSF2/GM-CSF). This gene, together with those for interleukin 4 (IL4), interleukin 13 (IL13), and CSF2, form a cytokine gene cluster on chromosome 5. This cytokine, IL4, and IL13 are found to be regulated coordinately by long-range regulatory elements spread over 120 kilobases on chromosome 5q31.

PLGF is a growth factor active in angiogenesis, and endothelial cell growth, stimulating their proliferation and migration. It binds to receptor vegfr-1/flt1.

A 88-kDa progranulin, also called proepithelin and PC cell-derived growth factor, is a single precursor protein of granulins which are a family of secreted, glycosylated peptides that are cleaved from a single precursor protein with 7.5 repeats of a highly conserved 12-cysteine granulin/epithelin motif. Granulins are a variety of active, 6 kDa peptides and named granulin A (epithelin 1), granulin B (epithelin 2), granulin C, etc. Both the peptides and intact progranulin protein regulate cell growth. However, different members of the granulin protein family may act as inhibitors, stimulators, or have dual actions on cell growth. Granulin family members are important in normal development, wound healing, and tumorigenesis.

GMFB is part of the GMF subfamily of the larger actin-binding protein ADF family. GMFB is phosphorylated after phorbol ester stimulation, and is crucial for the nervous system. GMFB causes brain cell differentiation, stimulates neural regeneration and inhibits tumor cell proliferation. GMFB overexpression in astrocytes results in the increase of BDNF production. GMFB expression is increased by exercise, thus BDNF is important for exercise-induction of BDNF.

BDNF is crucial for the signal survival eukaryotes. BDNF is responsible for the development, repair, adaptation and proper functionality of the nervous system.
BDNF major roles include Neuron survival and development, synaptic flexibility, stress adaptation, Repair and recovery post injury/disease and Pain signaling.

Fibroblast Growth Factor-19 (FGF-19) is a member of the FGF family. FGF-19 interacts with FGFR1, FGFR2, FGFR3 and FGFR4. T FGF-19 takes part in the suppression of bile acid biosynthesis through downregulation of CYP7A1 expression, following positive regulation of the JNK and EPK1/2 cascades. FGF-19 stimulates glucose uptake in adiposytes and is a high affinity, heparin dependent ligand for FGFR4.

Thymic Stromal Lymphopoietin Receptor (TSLPR) is a member of the type I cytokine receptor family. TSLPR alongside the interleukin 7 receptor (IL7R) activate STAT3, STAT5, and JAK2 pathways, which is regulated processes such as cell proliferation and development of the hematopoietic system. Two transcript variants encoding dissimilar isoforms have been found for this gene. TSLPR is expressed in heart, skeletal muscle, kidney and adult and fetal liver.

EIF1 is important for scanning and plays a role in initiation site selection. EIF1 promotes the assembly of 48S ribosomal at the authentic initiation codon of a conventional capped mRNA.

Nephroblastoma Overexpressed (NOV) which is encoded by the NOV gene is a part of the CCN (CTGF/CYR61/NOV) family. NOV takes part in reducing tumorgenicity and proliferation of certain cancer cell lines. NOV interacts with numerous proteins and is involved in both internal and external cell signaling. NOV is expressed in particular tumors, including Wilm’s tumor and most nephroblastomas and is also exerts proangiogenic activities.

GDF-5 is a member of the bone morphogenetic protein (BMP) family and the TGF-beta superfamily. This group of proteins is characterized by a polybasic proteolytic processing site which is cleaved to produce a mature protein containing seven conserved cysteine residues. The members of this family are regulators of cell growth and differentiation in both embryonic and adult tissues. Mutations in this gene are associated with acromesomelic dysplasia, Hunter-Thompson type; brachydactyly, type C; and chondrodysplasia, Grebe type. These associations confirm that the gene product plays a role in skeletal development.

Vascular endothelial growth factoris an important signaling proteininvolved in both vasculogenesisand angiogenesis. As its name implies, VEGF activity has been mostly studied on cells of the vascular endothelium, although it does have effects on a number of other cell types (e.g. stimulation monocyte/macrophagemigration, neurons, cancer cells, kidney epithelial cells ).VEGF mediates increased vascular permeability, induces angiogenesis, vasculogenesis and endothelial cell growth, promotes cell migration, and inhibits apoptosis. In vitro, VEGF has been shown to stimulate endothelial cell mitogenesisand cell migration. VEGF is also a vasodilator and increases microvascular permeability and was originally referred to as vascular permeability factor.
Elevated levels of this protein is linked to POEMS syndrome, also known as Crow-Fukase syndrome. Mutations in this gene have been associated with proliferative and nonproliferative diabetic retinopathy.

FGF-basic is a member of the fibroblast growth factor (FGF) family. FGF family members bind heparin and possess broad mitogenic and angiogenic activities. This protein has been implicated in diverse biological processes, such as limb and nervous system development, wound healing, and tumor growth. The mRNA for this gene contains multiple polyadenylation sites, and is alternatively translated from AUG and non-AUG (CUG) initiation codons resulting in 5 different isoforms with distinct properties. The CUG-initiated isoforms are localized in the nucleus and are responsible for the intracrine effect, whereas, the AUG-initiated form is mostly cytosolic and is responsible for the paracrine and autocrine effects of this FGF.
The heparin-binding growth factors are angiogenic agents in vivo and are potent mitogens for a variety of cell types in vitro. there are differences in the tissue distribution and concentration of these 2 growth factors.

YY1 Transcription Factor, also known as YY1, is a part of the GLI-Kruppel class of zinc finger proteins. YY1 has a positive and negative effect on a various cellular and viral genes by binding to sites overlapping the transcription start site. YY1 leads histone deacetylases and histone acetyltransferases to a promoter in order to activate or repress the promoter.

TNFRSF14, a member of the TNF receptor superfamily, is a type I transmembrane protein. TNFRSF14 is expressed in peripheral blood T cells, B cells, monocytes and in various tissues enriched in lymphoid cells. TNFRSF14 operates as a co-stimulatory factor for the activation of lymphoid cells and as a deterrent to infection by herpesvirus. Additionally, TNFRSF14 encourages the proliferation of T cells, and triggers apoptosis of various tumor cells.

GDNF family receptor alpha-1 (GFRA1) belongs to the GDNF receptor family. GFRA1 is a glycosyl-phosphatidylinositol(GPI)-linked cell surface receptor for both Glial cell line-derived growth factor (GDNF), neurturin (NTN), and mediates activation of the RET tyrosine kinase receptor. The GFRA1 protein is a potent survival factor for central and peripheral neurons, and is vital for the development of kidneys and the enteric nervous system.

Epidermal growth factor has a profound effect on the differentiation of specific cells in vivo and is a potent mitogenic factor for a variety of cultured cells of both ectodermal and mesodermal origin. The EGF precursor is believed to exist as a membrane-bound molecule which is proteolytically cleaved to generate the 53-amino acid peptide hormone that stimulates cells to divide.
EGF stimulates the growth of various epidermal and epithelial tissues in vivo and in vitro and of some fibroblasts in cell culture.

TNFR2 belongs to the TNF-receptor superfamily. TNFR2 is receptor with high affinity for TNFSF2/TNF-alpha and approximately 5-fold lower affinity for homotrimeric TNFSF1/lymphotoxin-alpha. TNFR2 mediates the majority of the metabolic effects of TNF-alpha. In addition, knockout studies in mice propose a role for TNFR2 in protecting neurons from apoptosis by stimulating antioxidative pathways. TNFR2 expression might have a significant role in the angiogenesis, tumor cell proliferation and metastasis of Invasive micropapillary carcinoma of the breast.
There are 2 types of soluble TNF receptors: sTNFR-I and sTNFR-II, which act to neutralize the biological activities of TNF alpha and TNF beta. The levels of these soluble receptors seem to increase as a result of shedding of the extracellular domains of the membrane bound receptors. High levels of soluble TNF receptors are found in the amniotic fluid of pregnant women. TNFR2 and TNFR1 form a heterocomplex which mediates the recruitment of 2 anti-apoptotic proteins, c-IAP1 and c-IAP2, which possess E3 ubiquitin ligase activity. IAPs’ function in TNF-receptor signaling is unknown; nevertheless, c-IAP1 is believed to potentiate TNF-induced apoptosis by the ubiquitination and degradation of TNF-receptor-associated factor 2, which mediates anti-apoptotic signals. Oxidative stress promotes TNFR1 and TNFR2 self-interaction, ligand-independent and enhanced ligand-dependent TNF signaling. TNF-a, TNFR1 and TNFR2 have roles in cellular differentiation. TNFR1 and TNFR2 function in cell type-specific renal injury.

STAT1 is a member of the Signal Transducers and Activators of Transcriptionfamily of transcription factors. STAT1 is involved in upregulating genes due to a signal by either type Ior type IIinterferons. In response to IFN-?stimulation, STAT1 forms homodimers or heterodimers with STAT3that bind to the GAS (Interferon-Gamma Activated Sequence) promoter element; in response to either IFN-? or IFN-?stimulation, STAT1 forms a heterodimer with STAT2that can bind the ISRE (Interferon Stimulated Response Element) promoter element. In either case, binding of the promoter element leads to an increased expression of ISG (Interferon Stimulated Genes).

Hypoxia-inducible factor-1 (HIF-1), identified as one of the transcription factors, has been found to play an essential role in cellular and systemic oxygen homeostasis. HIF-1 is a heterodimer composed of HIF-1b subunit and one of three subunits (Hif-1a, Hif-2 (or Hif-3)). The activation of Hif-1 (is closely associated with a variety of tumors and oncogenic pathways. Hif-1 (consists of DNA binding domain (DBD domain), Dimerization domain and C-terminal regulatory domains, including two transactivation domains (TAD), an oxygen-dependent degradation (ODD) domain, and inhibitory domains. Under hypoxic conditions HIF1A activates the transcription of more than 40 genes, including, erythropoietin, glucose transporters, glycolytic enzymes, VEGF, and other genes whose protein products increase oxygen delivery or facilitate metabolic adaptation to hypoxia. HIF-1A also plays a crucial role in embryonic vascularization, tumor angiogenesis and pathophysiology of ischemic disease. It binds to core DNA sequence 5'-[AG]CGTG-3' within the hypoxia response element (HRE) of target gene promoters. Activation involves recruitment of transcriptional coactivators such as CREBPB and EP300. Its activity is improved by interaction with both, NCOA1 or NCOA2. Interaction with redox regulatory protein APEX appears to activate CTAD and potentiates activation by NCOA1 and CREBBP. The induction is under reduced oxygen tension. HIF1A is also induced by a variety of receptor-mediated factors such as growth factors, cytokines, and circulatory factors for example PDGF, EGF, FGF-2, IGF-2, TGF-1 beta, HGF, TNF alpha, IL-1 beta, angiotensin-2 and thrombin. Nevertheless, this induction is less intense than that stimulated by hypoxia.

Interleukin 10 or IL-10 or human cytokine synthesis inhibitory factor, is a cytokine (anti-inflammatory). IL10 gene is coding for il-10 In humans. Interleukin 10 has a receptor complex that is built from a couple of IL-10 receptor-1 and a couple of IL-10 receptor-2 proteins. therfore, the whole receptor unit consists of four IL-10 receptor molecules. IL-10 binds the receptor and causes STAT3 signalling through the phosphorylation of the cytoplasmic ends of IL-10 receptor 1 and IL-10 receptor 2 through JAK1 and Tyk2.

POU2AF1 is a lymphocyte specific transcription coactivator protein. POU2AF1 cooperates only with the Oct1/2 proteins using sub domains in the POU domain of the Oct1/2 proteins, increasing their transcriptional efficiency. Even though POU2AF1 have no basic ability to bind DNA, it links firmly with the octomer motif in the presence of Oct1 and Oct2. POU2AF1 is expressed at maximum levels in spleen and peripheral blood leukocytes.

ASF1A is part of the H3/H4 family of histone chaperone proteins corresponding to the anti-silencing function-1 gene in yeast. ASF1A is an important element of the histone donor complex that functions in nucleosome assembly. ASF1A interacts with histones H3 and H4, and functions together with a chromatin assembly factor during DNA replication and repair. Deletion of ASF1A in yeast and Drosophila confers sensitivity to various DNA damaging agents and inhibitors of DNA replication, increases genomic instability and sister chromatid exchange, and activates the DNA damage checkpoint.

TNFRSF14, a member of the TNF receptor superfamily, is a type I transmembrane protein. TNFRSF14 is expressed in peripheral blood T cells, B cells, monocytes and in various tissues enriched in lymphoid cells. TNFRSF14 operates as a co-stimulatory factor for the activation of lymphoid cells and as a deterrent to infection by herpesvirus. Additionally, TNFRSF14 encourages the proliferation of T cells, and triggers apoptosis of various tumor cells.