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Abstract Background The lipocalin (LCN) family of structurally conserved hydrophobic ligand binding proteins is represented in all major taxonomic groups from prokaryotes to primates. The importance of lipocalins in reproduction and the similarity to known epididymal lipocalins prompted us to characterize the novel human epididymal LCN6. Methods and Results LCN6 cDNA was identified by database analysis in a comprehensive human library sequencing program. Macaca mulatta (rhesus monkey) cDNA was obtained from an epididymis cDNA library and is 93% homologous to the human. The gene is located on chromosome 9q34 adjacent LCN8 and LCN5. LCN6 amino acid sequence is most closely related to LCN5, but the LCN6 beta-barrel structure is best modeled on mouse major urinary protein 1, a pheromone binding protein. Northern blot analysis of RNAs isolated from 25 human tissues revealed predominant expression of a 1.0 kb mRNA in the epididymis. No other transcript was detected except for weak expression of a larger hybridizing mRNA in urinary bladder. Northern hybridization analysis of LCN6 mRNA expression in sham-operated, castrated and testosterone replaced rhesus monkeys suggests mRNA levels are little affected 6 days after castration. Immunohistochemical staining revealed that LCN6 protein is abundant in the caput epithelium and lumen. Immunofluorescent staining of human spermatozoa shows LCN6 located on the head and tail of spermatozoa with the highest concentration of LCN6 on the post-acrosomal region of the head, where it appeared aggregated into large patches. Conclusions LCN6 is a novel lipocalin closely related to Lcn5 and Lcn8 and these three genes are likely products of gene duplication events that predate rodent-primate divergence. Predominant expression in the epididymis and location on sperm surface are consistent with a role for LCN6 in male fertility.

Background: The lipocalin (LCN) family of structurally conserved hydrophobic ligand binding proteins is represented in all major taxonomic groups from prokaryotes to primates. The importance of lipocalins in reproduction and the similarity to known epididymal lipocalins prompted us to characterize the novel human epididymal LCN6. Methods and Results: LCN6 cDNA was identified by database analysis in a comprehensive human library sequencing program. Macaca mulatta (rhesus monkey) cDNA was obtained from an epididymis cDNA library and is 93% homologous to the human. The gene is located on chromosome 9q34 adjacent LCN8 and LCN5. LCN6 amino acid sequence is most closely related to LCN5, but the LCN6 beta-barrel structure is best modeled on mouse major urinary protein 1, a pheromone binding protein. Northern blot analysis of RNAs isolated from 25 human tissues revealed predominant expression of a 1.0 kb mRNA in the epididymis. No other transcript was detected except for weak expression of a larger hybridizing mRNA in urinary bladder. Northern hybridization analysis of LCN6 mRNA expression in sham-operated, castrated and testosterone replaced rhesus monkeys suggests mRNA levels are little affected 6 days after castration. Immunohistochemical staining revealed that LCN6 protein is abundant in the caput epithelium and lumen. Immunofluorescent staining of human spermatozoa shows LCN6 located on the head and tail of spermatozoa with the highest concentration of LCN6 on the post-acrosomal region of the head, where it appeared aggregated into large patches. Conclusions: LCN6 is a novel lipocalin closely related to Lcn5 and Lcn8 and these three genes are likely products of gene duplication events that predate rodent-primate divergence. Predominant expression in the epididymis and location on sperm surface are consistent with a role for LCN6 in male fertility. [ABSTRACT FROM AUTHOR]

Obesity is a major risk factor for a number of disorders ranging from type II diabetes to cardiovascular disease, however, the molecular basis for these associations has not been be fully clarified. A number of adipokines, cytokines expressed exclusively or at an elevated level in adipose tissue, have been identified that play key roles in regulating energy homeostasis by affecting insulin sensitivity, glucose and lipid metabolism and satiety. Dysregulated expression of adipokines may link obesity with its related metabolic disorders. We have developed a proteomics platform that enables the direct identification and functional characterization of adipokines from cells derived from human subcutaneous and visceral adipose depots. Adipocytes isolated from different fat depots (subcutaneous and visceral) from subjects with a spectrum of BMI (19-42) and diabetic progression, were subjected to Mass Spectrometric (MS) analyses. Preadipocytes isolated from adipose tissue were differentiated for 2 weeks, before being incubated in conditioned medium. Secreted and shed proteins released into the medium were labeled with ICAT and digested with trypsin. The cysteine-containing peptides were subjected to Liquid Chromatography (LC) / MS analysis. Peptide maps representing different adipocyte populations were compared and candidates that were differentially expressed were selected. Sequence-composition was resolved through tandem MS and database search. The functionality of a number of these adipokines was evaluated in a series of RNAi-based assays, established in human adipocytes, to determine the possible involvement of these secreted proteins in key metabolic transitions including: lipolysis and glucose uptake. Our systematic proteomic analysis has resulted in the identification of > 20 adipokines. A number of previously characterized secreted proteins, including visfatin and complement C1r were identified. In addition, a number of novel candidates that included: a protease inhibitor, a hydrolase and a molecule involved in cell-adhesion, were also resolved. Interestingly, subsequent comparison of the MS maps within the adipocyte samples revealed significant differences in expression of secreted / shed proteins isolated from: (i) subcutaneous and visceral depots, (ii) lean and obese subjects and (iii) normal and diabetic patients. [ABSTRACT FROM AUTHOR]

Objectives: Early detection of disease enables prompt treatment that can prevent disease progression and costly health outcomes. We report incidence of previously unrecognized disease and investigate the expected effect of early detection and care on health outcomes., Study Design: Population health study based on laboratory evidence., Methods: Laboratory evidence of prediabetes, diabetes, chronic kidney disease, and colorectal cancer was evaluated in an employee and spouse population (65% women; mean [SD] age = 46 [12] years). Expected disease progression was assessed., Results: Annual screening found laboratory evidence for 1185 previously unrecognized cases of prediabetes, 287 cases of diabetes, 73 cases of chronic kidney disease, and 669 positive colorectal screens per 10,000 people., Conclusions: Early identification and appropriate medical care may delay 34 cases of end-stage kidney disease and prevent diabetes-related complications, 210 cases of diabetes, and 3 cases of late-stage colorectal cancer over 5 years per 1000 cases identified.