Formation of new capillary blood vessels, termed angiogenesis, is essential for the growth and development of tissues and underlies a variety of diseases including tumor growth. Members of the prolactin hormonal family bind to endothelial cell receptors and have direct effects on cell proliferation, migration and tube formation. Because many angiogenic and antiangiogenic factors are produced by endothelial cells, we investigated whether endothelial cells expressed the prolactin gene. Here we show that bovine brain capillary endothelial cells (BBCEC) in culture express the full-length prolactin messenger RNA, in addition to a novel prolactin transcript, lacking the third exon of the gene. In addition cultures of BBCEC synthesize and secrete prolactin-like immunoreactive proteins with apparent molecular masses of 23, 21 and 14 kDa. The prolactin-like nature of these proteins is supported by the observation that Nb2-cells, a prolactin-responsive cell line, were stimulated to proliferate when co-cultured with endothelial cells and this stimulation was neutralized with prolactin-directed antibodies. Finally, consistent with a possible autocrine effect of endothelial-derived prolactins, polyclonal and monoclonal prolactin antibodies specifically inhibited basal and basic fibroblast growth-factorstimulated growth of endothelial cells. Taken together, the present findings support the hypothesis of the prolactin gene being expressed in endothelial cells as proteins that could act in an autocrine fashion to regulate cell proliferation.

Prolactin (PRL), originally associated with milk secretion, is now known to possess a wide variety of biological actions and diverse sites of production beyond the pituitary. Proteolytic cleavage is a common post-translational modification that can either activate precursor proteins or confer upon the peptide fragment unique biological actions not exerted by the parent molecule. Recent studies have demonstrated that the 16-kDa Nterminal proteolytic cleavage product of PRL (16K-PRL) acts as a potent inhibitor of angiogenesis. Despite previous demonstrations of 16K-PRL production in vivo, biological functions beyond its antiangiogenic actions remain unknown. Here we show that 16K-PRL, but not full-length PRL, acts to promote the expression of the inducible isoform of nitric oxide synthase (iNOS) and nitric oxide ( ⅐ NO) production by pulmonary fibroblasts and alveolar type II cells with potency comparable with the proinflammatory cytokines interleukin-1␤, interferon ␥, and tumor necrosis factor ␣. The differential effect of 16K-PRL versus PRL occurs through a receptor distinct from known PRL receptors. Additionally, pulmonary fibroblasts express the PRL gene and endogenously produce 16K-PRL, suggesting that this pathway may serve both autocrine and paracrine roles in the regulation of ⅐ NO production. These results reveal that proteolytic cleavage of PRL confers upon this classical hormone potent iNOS inducing activity, suggesting its role in inflammatory/immune processes. Although PRL1 was originally identified as a lactotrophic hormone secreted by the pituitary gland, accumulating evidence has implicated PRL in a strikingly diverse array of physiological functions, including osmoregulation, reproduction, and behavioral modifications (1, 2). PRL synthesis has been demonstrated in numerous extra-pituitary tissues, including endothelial (3), neuronal, and immune cells (i.e. lymphocytes, mononuclear cells, and thymocytes) (1). Moreover, the emerging role of PRL in immunoregulation has led to the concept of a dual function for PRL as both a circulating hormone and a cytokine (1). The tenet of PRL as a cytokine is further established by studies demonstrating its structural similarity to members of the cytokine/hematopoietin family (4) and that PRL receptors belong to the cytokine/hematopoietin receptor superfamily (5). Perturbation of PRL physiology appears to have significant immunologic effects in humans, where hyperprolactinemia is associated with autoimmune diseases, including systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, and uveitis (6). All these conditions are also associated with elevated tissue iNOS expression and ⅐ NO production (7). Consistent with these observations, hyperprolactinemia has been associated with elevated ⅐ NO levels in a rat model of acute inflammation (8).PRL can be post-translationally processed by proteolytic cleavage, giving rise to 16K-PRL, a fragment that has unique antiangiogenic actions not shared with the full-length molecule (9 -11). 16K-PRL has been detec...

Members of the prolactin (PRL) hormonal family have direct effects on endothelial cell proliferation, migration and tube formation. Moreover, isoforms of PRL may function as autocrine regulators of endothelial cells. Bovine brain capillary endothelial cells (BBCEC) express the PRL gene, while anti-PRL antibodies inhibit BBCEC proliferation. Here, we show the expression of the PRL gene into various PRL isoforms in endothelial cells from the human umbilical vein. Reverse transcription-polymerase chain reaction of total RNA from human umbilical vein endothelial cells (HUVEC) detected the full-length PRL mRNA as well as a 100 bp smaller PRL transcript similar to the one previously reported in BBCEC. HUVEC were positive to PRL immunocytochemistry. In addition, various PRL immunoreactive proteins were detected in HUVEC extracts and HUVEC conditioned media by metabolic labelling immunoprecipitation analysis. These PRL immunorelated proteins had apparent molecular masses of 60, 23, 21, 16 and 14 kDa. In contrast to previous findings in BBCEC, HUVEC conditioned media contained very little PRL bioactivity as determined by the selective bioassay of Nb2 cell proliferation. Moreover, some polyclonal or monoclonal antibodies directed against PRL stimulated HUVEC proliferation, in contrast to the inhibitory effect seen in BBCEC. The present findings extend the previous observations about the expression of PRL gene in endothelial cells from bovine brain capillaries to human cells of the umbilical vein, implicating that endothelium from different types of vessels and species share the expression of PRL gene but may differ in the putative autocrine role of the PRL isoforms expressed.

Membrane receptors for the Fc portion of immunoglobulin G (IgG) antibodies (Fc(gamma)Rs) are expressed on almost every type of hematopoietic cells, where they mediate a wide variety of effector functions. A high degree of structural heterogeneity exists among Fc(gamma)Rs. The biological significance of such heterogeneity is unknown, since the structural diversity does not appear to be reflected in the binding specificity nor in the effector functions that each distinct receptor is able to mediate. Recent work has emphasized the essential role of protein tyrosine phosphorylation in the initiation of transmembrane signaling by these receptors. In this article we review the role of protein tyrosine phosphorylation in signal transduction by the different types of Fc(gamma)Rs in order to assess to what extent the structural heterogeneity of this receptor family is related to different activation pathways utilized by each of its members.

This study aims to portray the complex diversity of the Mexican Mestizo population, which represents 98.8% of the entire population of Mexico. We compiled extended haplotype data of the Y chromosome from populations in the Central Valley of Mexico (CVM), which were compared to other Mestizo and parental (Amerindian, European and African) populations. A complex ancestral relationship was found in the CVM population, suggesting cosmopolitan origins.Nevertheless, the most preeminent lineages point towards a European ancestry, where the R1b was the most frequent. In addition, important frequencies of Amerindian linages were also found in the Mestizo sample studied. Interestingly, the Amerindian ancestry showed a remarkable substructure, which was represented by the two main founding lineages: QL54 (x M3) and M3. However, even within each lineage a high diversity was found despite the small number of samples bearers of these lineages. Further, we detected important genetic differences between the CVM populations and the Mexican Mestizo populations from the north and south. This result points to the fact that Mestizo populations present different ancestral proportions, which are related to the demographic events that gave origin to each population. Finally, we provide additional forensic statistical parameters that are useful in the interpretation of genetic analysis where autosomal loci are limited. Our findings illustrate the complex genetic background 3 of the Mexican Mestizo population and reinforce the need to encompass more geographic regions to generate more robust data for forensic applications. Materials and Methods Population of studyBlood samples were collected from 231 unrelated men belonging to the Mexican Mestizo population having at least three generations of ancestors born in Mexico.The studied population was recruited from Mestizos living in the Central Valley of the country (North-Central and East-Central regions) (Figure 1). This population included 121 men from Querétaro and 63 men from Guanajuato (North-Central region), as well as 47 men from Puebla (East-Central region). 7Each individual signed an informed consent validated by the Ethics Committee of the Bimodi's Research Unit. In addition, genealogical data were also obtained from each person to ensure that the individuals were unrelated through at least three generations. Molecular Analysis Y-chromosome haplotypingGenomic DNA was extracted from peripheral blood leukocytes using Qiamp Statistical and phylogenetic analysis8 Population genetics parametersAllele and haplotype frequencies, number of alleles (k), haplotype diversity (HD), genetic diversity over loci (h), and mean pairwise differences were estimated using Arlequin v. 3.5 software (Excoffie et al. 2010). Number of unique haplotypes (nuh) was estimated by direct counting. The following forensic parameters were determined: discrimination capacity (DC) was calculated by the expression: DC=h/n, where "h" is the total number of different haplotypes and "n"is the total number of i...