Estudo da distribuição das proteínas relacionadas às teneurinas no sistema nervoso central de primatas não-humanos (Sapajus spp) e ratos (Rattus norvegicus)
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Data
2016-06-06
Autores
Silva, Kelly Regina Torres da [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
As teneurinas (TENs) representam uma família de proteínas transmembrana preservada entre as espécies, presente principalmente no sistema nervoso central (SNC). Nos vertebrados essa família é composta por quatro homólogos, denominados de teneurina-1 a -4 (Ten-1, Ten-2, Ten-3 e Ten-4). Estudos mostraram a presença das TENs em vias motoras, olfatórias e visuais, especialmente durante a neurogênese em aves e roedores. A análise da distribuição neuroanatômica das TENs em primatas poderia ampliar o conhecimento destas proteínas, contribuindo com achados funcionais recentes. Portanto, os propósitos deste estudo foram: 1) avaliar a distribuição dos neurônios que exibem imunorreatividade relacionada às TENs-“like immunoreactivity” (TENs-LI), em particular Ten-2-LI, Ten-3-LI e Ten-4-LI no SNC do primata não-humano (Sapajus spp); 2) realizar análise comparativa dos sítios de distribuição da proteína Ten-3 entre o SNC de primatas (Sapajus spp) e roedores (Rattus norvegicus), uma vez que a Ten-3 apresentou distribuição significante no SNC de primatas; 3) correlacionar a distribuição das TENs com seus ligantes endógenos denominados de latrofilinas (LPHNs-1, 2 e 3) em áreas do SNC de primatas. Para isso, cortes coronais do SNC de macacos (n=3) e de ratos (n=4) foram submetidos à técnica de imuno-histoquímica e analisados em microscopia de luz ou confocal. Os resultados demonstraram a distribuição de neurônios e fibras nervosas exibindo TENs-LI em todo o neuroeixo de primatas. Neurônios exibindo Ten-2-LI estiveram principalmente no tronco encefálico, como notado nos núcleos facial, oculomotor e coclear. Neurônios exibindo Ten-4-LI foram evidentes no tronco encefálico como núcleo de Edinger-Westphal, núcleo oculomotor e núcleos vestibulares; entretanto, a distribuição de fibras Ten-4-LI foi significante em alguns tratos do tronco encefálico, tais como no trato solitário e trato espinal do nervo trigêmeo. A distribuição dos neurônios e fibras nervosas Ten-3-LI foram difusamente distribuídas ao longo do SNC, sendo que esta imunomarcação se assemelhou a neuropeptídios secretores nos neurônios e fibras nervosas presentes nos núcleos hipotalâmicos, tais como no núcleo paraventricular e supra-óptico. Os resultados para Ten-3-LI em ratos foram em sua maioria correspondentes aos verificados em primata embora sendo neste último mais abrangente. A correlação da distribuição entre LPHNs e TENs em territórios do SNC de primatas evidenciou que a LPHN-1 e Ten-3-LI estiveram em áreas e neurônios correspondentes como núcleo paraventricular, supra-óptico e medula espinal. Estes resultados demonstraram que as TENs estão conservadas no SNC de primatas, apresentando imunomarcações associadas a membrana plasmática, assim como similar a neuropeptídios secretores, sugerindo que esta família de proteínas seja capaz de exercer outras funções, além da interação intercelular. As áreas que apresentaram correlação entre TENs e LPHNs no SNC de primatas reforçam a possível interação destas proteínas como tem sido sugerido na literatura e contribui para futuras perspectivas funcionais.
Teneurins (TENs) represent a transmembrane protein family preserved along animal species, mainly in the central nervous system (CNS). This protein family is constituted by four homologues, named as teneurin 1 to 4 (Ten-1, Ten-2, Ten-3 and Ten-4). Previous studies pointed out presence of TENs in motor, olfactory and visual systems in chicken and rodents, especially during neurogenesis. The neuroanatomic distribution analysis of TENs in the primate brain could provide additional information on this protein system, as well as support functional data from recent studies. Therefore, the purposes of the present study were: 1) to evaluate the distribution of neurons exhibiting TENs-like immunoreactivity (TENs-LI), in particular, Ten- 2-LI, Ten-3-LI and Ten-4-LI in the CNS of non-human primates (Sapajus spp); 2) to comparatively analyze the main brain regions exhibiting Ten-3-LI between primates (Sapajus spp) and rodents (Rattus norvegicus), since Ten-3-LI showed significant distribution in the CNS of primates; 3) To correlate TENsLI neurons with latrophilins (LPHNs-1, 2 and 3), an endogenous TENs ligand, in the CNS of primates. For this purpose, coronal histological sections of the CNS of non-human primates (n=3) and rats (n=4) were submitted to immunohistochemistry techniques and analyzed under light or confocal microscopes. Neurons and nerve fibers exhibiting TENs-LI were observed in all parts of the CNS in primates. Neurons showing Ten-2-LI were present mainly in the brainstem, such as facial, oculomotor and cochlear nuclei. Neurons exhibiting Ten-4-LI were evident in the brainstem such Edinger-Westphal nucleus, oculomotor and vestibular nuclei; whereas immunoreactive nerve fibers were significant in the brainstem tracts, such as solitary and trigeminal nerve tracts. The distribution of neurons and nerve fibers exhibiting Ten-3-LI were widely distributed in the CNS and a particular immunolabeling pattern similar to a secretory neuropeptide was present in hypothalamic nuclei, especially in paraventricular and supraoptic nuclei. Ten-3-LI distribution in the rat CNS was quite similar to that in primates; however, the latter showed a more pronounced and exuberant immunolabeling . In relation to LPHNs and TENs collocalization in the CNS of primates, the main data showed LPHN-1 and Ten-3-LI colocalization in neurons from paraventricular and supraoptic nuclei as well as in the spinal cord. These data demonstrated that TENs are preserved in the CNS of non-human primates, showing immunolabeling associated with the plasmatic membrane or similar to secretory neuropeptides, suggesting that the TENs system can exert other functions besides cellular interaction among neurons. The colocalization between TENs and LPHNs in the CNS of primates reinforces the possible interaction of these proteins, as suggested in recent studies.
Teneurins (TENs) represent a transmembrane protein family preserved along animal species, mainly in the central nervous system (CNS). This protein family is constituted by four homologues, named as teneurin 1 to 4 (Ten-1, Ten-2, Ten-3 and Ten-4). Previous studies pointed out presence of TENs in motor, olfactory and visual systems in chicken and rodents, especially during neurogenesis. The neuroanatomic distribution analysis of TENs in the primate brain could provide additional information on this protein system, as well as support functional data from recent studies. Therefore, the purposes of the present study were: 1) to evaluate the distribution of neurons exhibiting TENs-like immunoreactivity (TENs-LI), in particular, Ten- 2-LI, Ten-3-LI and Ten-4-LI in the CNS of non-human primates (Sapajus spp); 2) to comparatively analyze the main brain regions exhibiting Ten-3-LI between primates (Sapajus spp) and rodents (Rattus norvegicus), since Ten-3-LI showed significant distribution in the CNS of primates; 3) To correlate TENsLI neurons with latrophilins (LPHNs-1, 2 and 3), an endogenous TENs ligand, in the CNS of primates. For this purpose, coronal histological sections of the CNS of non-human primates (n=3) and rats (n=4) were submitted to immunohistochemistry techniques and analyzed under light or confocal microscopes. Neurons and nerve fibers exhibiting TENs-LI were observed in all parts of the CNS in primates. Neurons showing Ten-2-LI were present mainly in the brainstem, such as facial, oculomotor and cochlear nuclei. Neurons exhibiting Ten-4-LI were evident in the brainstem such Edinger-Westphal nucleus, oculomotor and vestibular nuclei; whereas immunoreactive nerve fibers were significant in the brainstem tracts, such as solitary and trigeminal nerve tracts. The distribution of neurons and nerve fibers exhibiting Ten-3-LI were widely distributed in the CNS and a particular immunolabeling pattern similar to a secretory neuropeptide was present in hypothalamic nuclei, especially in paraventricular and supraoptic nuclei. Ten-3-LI distribution in the rat CNS was quite similar to that in primates; however, the latter showed a more pronounced and exuberant immunolabeling . In relation to LPHNs and TENs collocalization in the CNS of primates, the main data showed LPHN-1 and Ten-3-LI colocalization in neurons from paraventricular and supraoptic nuclei as well as in the spinal cord. These data demonstrated that TENs are preserved in the CNS of non-human primates, showing immunolabeling associated with the plasmatic membrane or similar to secretory neuropeptides, suggesting that the TENs system can exert other functions besides cellular interaction among neurons. The colocalization between TENs and LPHNs in the CNS of primates reinforces the possible interaction of these proteins, as suggested in recent studies.
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Palavras-chave
Sistema nervoso central, Macaco, Ratos, Teneurinas, Central nervous system, Monkeys, Rats, Teneurins