Experimental transmission of bovine spongiform encephalopathy (BSE) to cynomolgus macaques, a non-human primate.

Bovine spongiform encephalopathy (BSE) was transmitted to three macaques by intracerebral inoculation of a brain homogenate from affected cattle detected in Japan. All monkeys developed abnormal behavioral signs, such as intermittent anorexia and hyperekplexia, around 24 months after inoculation. Neuronal symptoms, such as tremor, myoclonic jerking, and paralysis, appeared 27-44 months after inoculation. These symptoms worsened and total paralysis ensued within a year after onset. The disease duration was approximately 8-12 months. Both the incubation period and the duration of disease were shortened in the secondary transmission experiment to macaques. Heavy accumulation of disease-causing conformer(s) of prion protein (PrP(Sc)), with a similar glycoform profile to the PrP(Sc) contained in the inoculum, and severe spongiform changes in the histology of the brain, confirmed the successful transmission of BSE to monkeys. Florid plaques, a characteristic histological hallmark of variant Creutzfeldt-Jakob disease, were prominent in the cerebral cortex, in which a prion antigen was detected by immunohistochemistry (IHC). PrP(Sc) was mostly confined to the central nervous system, although small amounts of PrP(Sc) accumulated in the peripheral nerves of monkeys, as detected by Western blotting (WB). Neither IHC nor WB detected PrP(Sc) in the lymphatic organs/tissues, such as the tonsils, spleen, and appendix.

Atypical L-type bovine spongiform encephalopathy (L-BSE) transmission to cynomolgus macaques, a non-human primate.

A low molecular weight type of atypical bovine spongiform encephalopathy (L-BSE) was transmitted to two cynomolgus macaques by intracerebral inoculation of a brain homogenate of cattle with atypical BSE detected in Japan. They developed neurological signs and symptoms at 19 or 20 months post-inoculation and were euthanized 6 months after the onset of total paralysis. Both the incubation period and duration of the disease were shorter than those for experimental transmission of classical BSE (C-BSE) into macaques. Although the clinical manifestations, such as tremor, myoclonic jerking, and paralysis, were similar to those induced upon C-BSE transmission, no premonitory symptoms, such as hyperekplexia and depression, were evident. Most of the abnormal prion protein (PrP(Sc)) was confined to the tissues of the central nervous system, as determined by immunohistochemistry and Western blotting. The PrP(Sc) glycoform that accumulated in the monkey brain showed a similar profile to that of L-BSE and consistent with that in the cattle brain used as the inoculant. PrP(Sc) staining in the cerebral cortex showed a diffuse synaptic pattern by immunohistochemistry, whereas it accumulated as fine and coarse granules and/or small plaques in the cerebellar cortex and brain stem. Severe spongiosis spread widely in the cerebral cortex, whereas florid plaques, a hallmark of variant Creutzfeldt-Jakob disease in humans, were observed in macaques inoculated with C-BSE but not in those inoculated with L-BSE.

Monitoring of gene expression in differentiation of embryoid bodies from cynomolgus monkey embryonic stem cells in the presence of bisphenol A.

An embryonic stem (ES) cell differentiation model would facilitate analysis of developmental processes at the cellular level and the effects of embryotoxic and teratogenic factors in vitro. We explored the use of differentiation of embryoid bodies (EBs) from cynomolgus monkey ES cells for embryotoxicity testing. We determined the mRNA expression of various genes using real-time RT-PCR. Oct-3/4 expression was almost completely suppressed on day 14, suggesting that ES cells reached differentiated status in around 14 days. mRNA expression of E-cadherin, connexin 43, caveolin-1, and argininosuccinate synthetase was reproducibly suppressed during EB differentiation in 7-32% of ES cells in three separate experiments. Although these may not be "general stemness marker genes" such as Oct-3/4, they could play a role in readying stem cells for differentiation in response to deletion of signals from feeder cells. Next, we examined the effects of bisphenol A (BPA) on the mRNA expression of several differentiation marker genes for ES cells. That of PAX-6, an ectoderm marker, with 0, 0.1, and 10 microM BPA in 21-day EBs was 3,500%, 6,668%, and 8,394%, respectively, compared with ES cells. The difference between doses of 0 and 10 microM BPA in 21-day EBs was statistically significant (p=0.049). Pax-6 activation in the presence of BPA may interfere with the development of eyes, sensory organs, and certain neural and epidermal tissues usually derived from ectodermal tissues. Differentiation of EBs from cynomolgus monkey ES cells could be a useful model for detecting gene expression changes in response to chemical exposure.