Analysis of prostate-specific antigen transcripts in chimpanzees, cynomolgus monkeys, baboons, and African green monkeys.

The function of prostate-specific antigen (PSA) is to liquefy the semen coagulum so that the released sperm can fuse with the ovum. Fifteen spliced variants of the PSA gene have been reported in humans, but little is known about alternative splicing in nonhuman primates. Positive selection has been reported in sex- and reproductive-related genes from sea urchins to Drosophila to humans; however, there are few studies of adaptive evolution of the PSA gene. Here, using polymerase chain reaction (PCR) product cloning and sequencing, we study PSA transcript variant heterogeneity in the prostates of chimpanzees (Pan troglodytes), cynomolgus monkeys (Macaca fascicularis), baboons (Papio hamadryas anubis), and African green monkeys (Chlorocebus aethiops). Six PSA variants were identified in the chimpanzee prostate, but only two variants were found in cynomolgus monkeys, baboons, and African green monkeys. In the chimpanzee the full-length transcript is expressed at the same magnitude as the transcripts that retain intron 3. We have found previously unidentified splice variants of the PSA gene, some of which might be linked to disease conditions. Selection on the PSA gene was studied in 11 primate species by computational methods using the sequences reported here for African green monkey, cynomolgus monkey, baboon, and chimpanzee and other sequences available in public databases. A codon-based analysis (dN/dS) of the PSA gene identified potential adaptive evolution at five residue sites (Arg45, Lys70, Gln144, Pro189, and Thr203).

Correlation between presence of Trypanosoma cruzi DNA in heart tissue of baboons and cynomolgus monkeys, and lymphocytic myocarditis.

Trypanosoma cruzi, the causative agent of Chagas' disease, preferentially infects cardiac and digestive tissues. Baboons living in Texas (Papio hamadryas) and cynomolgus monkeys (Macaca fascicularis) have been reported to be infected naturally with T. cruzi. In this study, we retrospectively reviewed cases of animals that were diagnosed with lymphocytic myocarditis and used a polymerase chain reaction (PCR)-based method (S36/S35 primer set) to amplify T. cruzi DNA from archived frozen and formalin-fixed paraffin-embedded (FFPE) cardiac tissues. We show that the PCR method is applicable in archived frozen and FFPE tissues and the sensitivity is in the femtogram range. A positive correlation between PCR positivity and lymphocytic myocarditis in both baboons and cynomolgus monkeys is shown. We also show epicarditis as a common finding in animals infected with T. cruzi.

Androgen receptor CAG repeat polymorphism in males of six non-human primate species.

BACKGROUND: Androgen receptor [CAG](n) microsatellite has been linked to human diseases. METHODS: Six non-human primates were genotyped for the [CAG](n) microsatellite. RESULTS: Marmosets and macaques are monomorphic, while mangabeys, baboons, and chimpanzees are polymorphic. CONCLUSIONS: Non-human primates that are polymorphic for the microsatellite are candidate animal models for CAG-related diseases.

Serum prostate specific antigen changes in cynomolgus monkeys (Macaca fascicularis) on a high sugar high fat diet.

BACKGROUND: An inverse relationship between serum prostate specific antigen (PSA) levels and body mass index (BMI) has been reported in men but not in any animal model. METHODS: Serum PSA in a colony of cynomolgus monkeys was assayed and correlated to body weight, prostate weight, and age. In addition, 15 animals were selected and fed a high sugar high fat (HSHF) diet for 49 weeks to increase their BMI and correlate it to PSA RESULTS: Serum PSA levels were positively correlated to prostate weight (r = 0.515, P = 0.025) and age (r = 0.548, P = 0.00072) but was not significantly correlated to body weight (r = -0.032, P = 0.419). For the animals on the HSHF diet, body weight, lean mass, fat mass, and BMI were significantly higher at 49 weeks than at baseline (P < 0.01). PSA was not significantly correlated to body weight and insulin at both baseline and 49 weeks. PSA was negatively correlated to BMI and insulin resistance (HOMA-IR) at 49 weeks but not at baseline. In addition, we observed hepatic steatosis and increases in serum liver enzymes. CONCLUSIONS: Increases in BMI in cynomolgus monkeys as a result of consuming a HSHF diet resulted in PSA changes similar to those in humans with increased BMI. Cynomolgus monkeys are a useful model for investigating the relationship between obesity, diabetes, and PSA changes resulting from prostate gland pathology.

A preliminary report on the feeding of cynomolgus monkeys (Macaca fascicularis) with a high-sugar high-fat diet for 33 weeks.

BACKGROUND: The metabolic syndrome is common in populations exposed to a typical Western diet. There is a lack of an animal model that mimics this condition. METHODS: We fed 15 cynomolgus monkeys ad libitum a high-sugar high-fat (HSHF) diet for 33 weeks. Body weight, body composition, serum lipids, and insulin were measured at baseline and at 33 weeks. RESULTS: The animals tolerated the HSHF diet very well. In the intervention group, total serum cholesterol and low-density lipoprotein cholesterol were 3- and 5-fold higher, respectively, at 33 weeks as compared with their baseline levels. Serum high-density lipoprotein cholesterol and triglycerides were not significantly affected. Dual-energy X-ray absorptiometry (DXA) analysis of the intervention group indicated that the trunk fat mass increased by 187% during this period. CONCLUSIONS: Cynomolgus monkeys should be a useful model for investigating the interactions of diet and other factors such as genetics in the development of the metabolic syndrome.

Polymerase chain reaction detection of Trypanosoma cruzi in Macaca fascicularis using archived tissues.

This study describes conventional and real-time polymerase chain reaction (PCR) methods developed to detect and quantify Trypanosoma cruzi DNA in cynomolgus monkeys (Macaca fascicularis) using formalin-fixed paraffin-embedded blocks archived for periods of up to 6 years. The highest concentration of T. cruzi DNA was found in the myocardium, urinary bladder, stomach, lymph node, adrenal gland, and colon. The concentration of T. cruzi DNA detected in cardiac tissues was 10-100-fold greater than found elsewhere; the mean concentrations of T. cruzi DNA in non-cardiac tissues were otherwise comparable. Trypanosoma cruzi DNA was amplified from cerebrum but not cerebellum or kidney. Successful use of DNA from formalin-fixed, paraffin-embedded blocks is important because most pathology laboratories routinely archive wax blocks. This archived resource can be used for further studies on the prevalence of this disease.

Spontaneous heart disease in the adult chimpanzee (Pan troglodytes).

BACKGROUND: A high incidence of heart disease, especially idiopathic cardiomyopathy (IC), is seen in chimpanzees (Pan troglodytes). METHODS: We reviewed clinical records and necropsy reports of 87 adult chimpanzees for possible causes of heart disease/IC. We examined age, sex, cause of death, weight, diet, environment, infectious diseases, experimental uses and clinical pathology. RESULTS: The overall prevalence of heart disease in chimpanzees was 67.81%; the prevalence of IC was 51.72%. The prevalence of IC was significantly higher in males (60.32%) than that in females (29.17%, P = 0.009). The prevalence of other heart disease was higher in females (25%) than that in males (12.70%, P = 0.165). Heart failure occurred in 47.13% of chimpanzees. Heart disease was the primary cause of death in 34.49% of chimpanzees; 29.88% died of unknown causes. CONCLUSIONS: We found no evidence that diet, environment, viral agents, experimental use or disease exposure contributed to the deaths resulting from IC in chimpanzees.

Nonhuman primates as models for studies of prostate specific antigen and prostatic diseases.

BACKGROUND: Because prostate specific antigen (PSA) is released at increased levels into the blood early in the development of prostate cancer, benign prostatic hyperplasia (BPH) and prostatitis, it is widely used as a marker for these diseases. However, PSA has clinical limitations as a screen for prostatic diseases due to its low sensitivity and specificity. There is a strong need to better understand the biology of PSA and factors affecting its serum levels. METHODS: We evaluated cynomolgus macaques, rhesus macaques, baboons, and marmosets for their suitability as models for the study of PSA biology and prostatic diseases. RESULTS: Prostates of several nonhuman primates are anatomically similar to the human counterpart. Anti-human PSA antibody detected PSA antigens in all the Old World monkeys (cynomolgus macaques, rhesus macaques, and baboons) but not in marmosets. Of the Old World monkeys, cynomolgus macaques have the highest serum PSA levels; baboons have the lowest. Serum PSA levels from macaques includes a number of outlier samples with unusually high values. We also report two cases of abnormal pathologies in macaques accompanied by high serum PSA levels. One case consisted of prostatic hyperplasia involving both glandular and basal cells in a cynomolgus macaque and another of glandular hyperplasia and atrophy in a rhesus macaque. The finding that pathological changes in the prostate of macaques may lead to increases in serum PSA is worthy of further exploration. CONCLUSION: Cynomolgus macaques and rhesus macaques are promising animal models for PSA biology studies.

A preliminary study of the baboon prostate pathophysiology.

BACKGROUND: Prostate cancer, benign prostatic hyperplasia, and prostatitis frequently affect men worldwide. At present there are no suitable animal models for these diseases. This study explores the potential use of the baboon as a model for prostatic diseases. METHODS: Prostates of 48 baboons of different ages were studied. Prostate specific antigen (PSA) and alpha-methyl-acyl-CoA racemase (AMACR) were localized in the different lobes of the prostate by Western blotting and immunohistochemistry. PSA in baboon serum was demonstrated by radioimmunoassay and western blotting. Baboon AMACR cDNA was cloned and its expression assayed in baboon tissues. RESULTS: The baboon prostate is anatomically and histologically similar to its human counterpart, with cranial and caudal lobes corresponding to central and peripheral zones of the human prostate. We found lymphocytic infiltration (91%), and sclerosing/atrophic lesions (34%). PSA tissue immunostaining intensity and alpha-methyl-acyl-CoA racemase (AMACR) gene expression levels differed between the cranial and caudal lobes of the prostate. The cloned baboon AMACR cDNA showed 96% homology with its human counterpart. Anti-human AMACR, PSA and basal keratin antibodies stained intracellular and basement membrane structures in the baboon prostate. The sclerosing/atrophic lesions were comparable to their human counterparts. CONCLUSIONS: The similarity of baboon prostate to its human counterpart and the fact that human antibodies (AMACR, PSA, basal keratin) are reactive to baboon prostatic proteins indicates that the baboon is a promising model for human prostatic diseases.

A variant of the alpha-methyl-acyl-CoA racemase gene created by a deletion in exon 5 and its expression in prostate cancer.

BACKGROUND: Alpha-methylacyl-CoA racemase (AMACR) is a mitochondrial and peroxisomal enzyme that is overexpressed in prostate cancer. Alternatively spliced variants of AMACR have recently been reported, however, their role in prostate cancer pathogenesis is unclear. METHODS: Using PCR techniques we have identified a novel variant of AMACR. RESULTS: This transcript arises by an alternative splicing event in the 5th exon of the gene whereby a 749 base sequence is deleted causing a shift in the reading frame. The protein encoded by this transcript has a predicted molecular weight of 43,833 kDa and a pI of 7.01 and therefore differs in size and physical characteristics from the main form of AMACR. The carboxyl terminus of this variant does not contain the peroxisomal targeting signal found in the main form of AMACR. Using real time PCR it was demonstrated that this transcript also occurs in normal prostate tissue and is elevated in prostate cancer. Coordinate expression of this transcript with the other forms of AMACR was shown. This transcript was expressed as a FLAG fusion protein in Cos-7 cells and probed with relevant antibodies. CONCLUSION: A deletion event in exon 5 of the AMACR gene creates a novel transcript that is coordinately expressed with the other forms of AMACR but with different biochemical characteristics. (c) 2005 Wiley-Liss, Inc.

Alternative spliced variants of the alpha-methylacyl-CoA racemase gene and their expression in prostate cancer.

Alpha-methyacyl-CoA racemase (AMACR), a mitochondrial and peroxisomal enzyme essential in lipid metabolism, is overexpressed in prostate cancer. Two different AMACR transcripts (designated IA and IIA), each derived from five exons, have been reported. AMACR IA, the most abundant form, encodes a 382-amino acid protein (Mw 42 kDa, pI 6.07). AMACR IIA contains an alternative fifth exon that has extensive homology to the human fumarate hydratase (FH) and encodes a 288-amino acid protein (Mw 32 kDa, pI 9.6). Here we report additional variants of IA and IIA whereby the transcripts lack exon 3 and are designated as IB (Mw 22 kDa, pI 10.31) and IIB (Mw 31 kDa, pI 9.44). Due to a frameshift, the alternative fifth exon in the IIA transcript encodes a polypeptide that differs from FH. In contrast, the IIB transcript, generated as a result of the dual alternative splicing events, encodes a polypeptide homologous with a highly conserved region of FH. We also identified a shorter variant form of IIA (IIAs, Mw 28 kDa, pI 9.65), which lacks the 5' half of the alternative fifth exon. The carboxy termini of all five gene products differ as a result of the alternative splicing events. In prostate tumor tissues that overexpressed AMACR, both the A and B forms were overexpressed, suggesting coregulation. Only the predominant AMACR IA has an acidic pI and contains the previously identified peroxisomal targeting signal (PTS1) peptide, while the other four variants are basic proteins that lack the peroxisomal targeting signal peptide. These observations have implications for the cellular localization and function of these AMACR variants.