RESUMO
BACKGROUND: Carbonic anhydrase VI (CA-VI) is produced by the salivary gland and is secreted into the saliva. Although CA-VI is found in the epithelial cells of distal straight tubule of swine kidneys, the exact function of CA-VI in the kidneys remains unclear. RESULTS: CA-VI was located in the epithelial cells of distal straight tubule of swine kidneys.A full-length cDNA clone of CA-VI was generated from the swine parotid gland by reverse transcription polymerase chain reaction, using degenerate primers designed based on conserved regions of the same locus in human and bovine tissues. The cDNA sequence was 1348 base pairs long and was predicted to encode a 317 amino acid polypeptide with a putative signal peptide of 17 amino acids. The deduced amino acid sequence of mature CA-VI was most similar (77.4%) to that of human CA-VI. CA-VI expression was confirmed in both normal and nephritic kidneys, as well as parotid. As the primers used in this study spanned two exons, the influence of genomic DNA was not detected. The expression of CA-VI was demonstrated in both normal and nephritic kidneys, and mRNA of CA-VI in the normal kidneys which was the normalised to an endogenous ß-actin was 0.098 ± 0.047, while it was significantly lower in the diseased kidneys (0.012 ± 0.007). The level of CA-VI mRNA in normal kidneys was 19-fold lower than that of the parotid gland (1.887). CONCLUSIONS: The localisation of CA-VI indicates that it may play a specialised role in the kidney.
Assuntos
Anidrases Carbônicas/genética , Células Epiteliais/metabolismo , Regulação Enzimológica da Expressão Gênica , Túbulos Renais Distais/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Anidrases Carbônicas/isolamento & purificação , Anidrases Carbônicas/metabolismo , Clonagem Molecular , DNA Complementar/química , DNA Complementar/genética , Células Epiteliais/enzimologia , Imuno-Histoquímica , Túbulos Renais Distais/citologia , Túbulos Renais Distais/enzimologia , Dados de Sequência Molecular , Nefrite/enzimologia , Nefrite/genética , Glândula Parótida/enzimologia , Glândula Parótida/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , SuínosRESUMO
This study investigated whether carbonic anhydrase (CA)-VI has utility as a biomarker in swine kidney disease. Serum chemistry, histopathology, immunohistochemical staining and enzyme-linked immunosorbent assay (ELISA) analyses were performed. In the kidney of normal healthy pigs, CA-VI was localized in the epithelial cells of the renal distal straight tubules. CA-VI levels were 16 ± 35 ng/g wet tissue and 50 ± 66 ng/mL in normal pig kidney and urine, respectively, and 136 ± 173 ng/mL in the urine of pigs with kidney disease. CA-VI urinary concentration was not correlated with urinary urea nitrogen (UUN), urinary creatinine (Cre), or urinary albumin levels in pigs with kidney disease. However, UUN and Cre levels were positively correlated in the urine of pigs with kidney disease. These data suggest that urinary CA-VI may represent a biomarker for kidney disease in pigs, particularly for disorders affecting distal straight tubules.