Susceptibilidade das células beta-pancreáticas ao SARS-CoV-2: uma revisão integrativa

Introduction: The pandemic caused by SARS-CoV-2 has brought numerous challenges to society, generating a huge global health burden in search of understandig this fenomenon. It is known that SARS-CoV-2 has manifestations that goes beyond respiratory involvement. Over time, knowledge about the mechanisms and tropisms of the virus has changed, allowing a greater understanding of the pathophysiology of COVID-19. Regarding the potential endocrine involvement caused by SARS-CoV-2, it is possible to observe that beta-pancreatic cells are susceptible to infection by the virus, and it is valid to investigate this correlation. For this reason, we sought to establish this relationship between SARS-CoV-2 infection and its effects on pancreatic beta cells. Methodology: The searches were carried out using defined keywords, finding studies indexed in the PubMed electronic database. Results: After a complete reading of the 63 articles selected using the inclusion and exclusion criteria, it was possible to observe that 42 portrayed some degree of susceptibility of pancreatic beta cells to SARS-CoV-2 infection. This study sought to demonstrate that SARS-CoV-2 infection is closely related to deleterious effects on pancreatic beta cells. Conclusion: By reviewing the selected articles, we came to the conclusion that SARS-CoV-2 is a virus that affects the human body in several different ways and can lead to Diabetes Mellitus (DM) if it affects the functioning of β-cells. We emphasize the importance of more studies in this area, since the consequences of the COVID-19 pandemic will follow humanity for a long time, and are extremely relevant to medical practice in the coming years.Introdução: A pandemia causada pela SARS-CoV-2 trouxe inúmeros desafios à sociedade, gerando uma enorme carga global de saúde em busca de sua compreensão. Sabe-se que a SARS-CoV-2 possui manifestações que vão além do acometimento respiratório. Ao longo do tempo, o conhecimento acerca dos mecanismos e tropismos do vírus se modificou, permitindo uma maior compreensão da fisiopatologia da COVID-19. Acerca do potencial acometimento endócrino causado pelo SARS-CoV-2, é possível observar que as células beta-pancreáticas são suscetíveis à infecção pelo vírus, sendo válida a investigação acerca de tal correlação. Por tal motivo, procuramos estabelecer essa relação entre a infecção pelo SARS-CoV-2 e seus efeitos sobre as células beta pancreáticas. Metodologia: As buscas foram realizadas com palavras-chave definidas, encontrando estudos indexados no banco de dados eletrônicos PubMed. Resultado: Após a leitura completa dos 63 artigos selecionados por meio dos critérios de inclusão e exclusão, foi possível observar que 42 retratam algum grau de susceptibilidade das células beta-pancreáticas à infecção por SARS-Cov-2. O presente trabalho procurou demonstrar que a infecção pelo SARS-CoV-2 está intimamente relacionada com efeitos deletérios às células beta pancreáticas. Conclusão: Através da revisão dos artigos selecionados, chegamos à conclusão de que o SARS-CoV-2 é um vírus que acomete o corpo humano de diversas maneiras diferentes, podendo gerar Diabetes Mellitus (DM) caso afete o funcionamento das células β. Ressaltamos a importância de mais estudos na área, visto que as consequências da pandemia do COVID-19 acompanharão a humanidade por um longo tempo, sendo de extrema relevância para a prática médica dos próximos anos

Nutritionally Driven Differential Gene Expression Leads to Heterochronic Brain Development in Honeybee Castes

<div><p>The differential feeding regimes experienced by the queen and worker larvae of the honeybee <i>Apis mellifera</i> shape a complex endocrine response cascade that ultimately gives rise to differences in brain morphologies. Brain development analyzed at the morphological level from the third (L3) through fifth (L5) larval instars revealed an asynchrony between queens and workers. In the feeding phase of the last larval instar (L5F), two well-formed structures, pedunculi and calyces, are identifiable in the mushroom bodies of queens, both of which are not present in workers until a later phase (spinning phase, L5S). Genome-wide expression analyses and normalized transcript expression experiments monitoring specific genes revealed that this differential brain development starts earlier, during L3. Analyzing brains from L3 through L5S1 larvae, we identified 21 genes with caste-specific transcription patterns (e.g., <i>APC-4, GlcAT-P, fax, kr-h1</i> and <i>shot</i>), which encode proteins that are potentially involved in the development of brain tissues through controlling the cell proliferation rate (APC4, kr-h1) and fasciculation (GlcAT-P, fax, and shot). <i>Shot</i>, whose expression is known to be required for axon extension and cell proliferation, was found to be transcribed at significantly higher levels in L4 queens compared with worker larvae. Moreover, the protein encoded by this gene was immunolocalized to the cytoplasm of cells near the antennal lobe neuropiles and proximal to the Kenyon cells in the brains of L4 queens. In conclusion, during the larval period, the brains of queens are larger and develop more rapidly than workers’ brains, which represents a developmental heterochrony reflecting the effect of the differential feeding regime of the two castes on nervous system development. Furthermore, this differential development is characterized by caste-specific transcriptional profiles of a set of genes, thus pointing to a link between differential nutrition and differential neurogenesis via genes that control cell proliferation and fasciculation.</p></div

<i>In situ</i> hybridization to detect <i>shot</i> expression in the brains of <i>A.</i><i>mellifera</i> workers and queens.

<p>Confocal images of brain of 4^th instar honeybee queens show <i>shot</i> mRNA throughout the entire organ (<b>A, D, G</b>). No mRNA was detected in worker brains in the 4^th instar (<b>B, E, H</b>), and expression only appeared in the 5^th stage (<b>C, F, I</b>). Green: shot mRNA; blue: DAPI. Note the <i>shot</i> mRNA surrounding nuclei.</p

Shot immunostaining during the 4^th larval instar of <i>A.</i><i>mellifera</i> castes.

<p>Triple labeling with DAPI (A, B), phalloidin staining (<b>C, D</b>) and anti-shot (mAbRod1; <b>E, F</b>). (<b>G</b>) Shot protein was immunolocalized to the cytoplasm of cells near the antennal lobe neuropiles (arrowhead) and proximal to the Kenyon cells in the brains of L4 queens (arrow). (<b>H</b>) As observed for mRNA, Shot protein was absent in worker brains in the 4^th larval instar. Confocal plane of a queen brain (<b>I</b>) showing Shot staining in the cytoplasm of cells (arrows and arrowheads).</p

Characteristics of the primers used in the RT-qPCR assays.

<p>Characteristics of the primers used in the RT-qPCR assays.</p

Developmental stages and characteristics of the <i>A. mellifera</i> larvae used in this work.

<p>Modified from Michelette and Soares <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0064815#pone.0064815-Michelette1" target="_blank">[17]</a> and Rembold et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0064815#pone.0064815-Rembold1" target="_blank">[18]</a>. L3 =  third larval instar; L4 = fourth larval instar; L5F2 = second feeding phase of the fifth larval instar; L5S1<b> = </b>first spinning stage of the fifth larval instar. Q = queens. W = workers.</p

Characteristics of genes whose expression was analyzed by RT-qPCR.

<p>Characteristics of genes whose expression was analyzed by RT-qPCR.</p

Transcription profile of genes associated with neurogenesis in the brains of <i>A.</i><i>mellifera</i> females of different castes.

<p>The ordinates represent the relative transcript levels assessed by RT-qPCR. The data were normalized to <i>ribosomal protein-49</i>. Three biological samples were analyzed in technical triplicates. L3, L4, L5F and L5S: larval stages; *: statistically significant differences between castes (two-way ANOVA, <i>p</i><0.05); <i>fax</i>: <i>failed axon connection; GlcAT-P</i>: <i>galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase P</i>; <i>kr-h1</i>: <i>krüppel homolog –1</i>; <i>crc: cryptocephal; EphR: Ephrin Receptor</i>; <i>shot: short stop</i>; <i>APC-4</i>: <i>anaphase promoting complex 4</i>; <i>tsp5D</i>: <i>tetraspanin 5D</i>; <i>atx-2</i>: <i>ataxin</i>-<i>2</i>; <i>dac</i>: <i>dachshund</i>.</p

Frontal view of the central neuropils in the 3^rd and 4^th larval instars of <i>A. mellifera</i> castes.

<p>Queen and worker brains are highlighted with phalloidin (red) and DAPI (blue). In these stages, there are clusters of neuroblasts (N) on each side of the brain (<b>A–D</b>). Phalloidin stains axons from optic tubercles (OT), inter-tubercle tracts (iTT) and the antennal lobe (AL) (<b>E–L</b>). No morphological differences can be observed between the castes at the 3^rd stage, whereas in the 4^th stage, the peduncles (Pe) of mushroom bodies start to develop in queen brains (<b>H, L</b>).</p

Differentially represented sequences obtained via microarray hybridization of samples from the brains of L4 workers and queens of <i>A. mellifera</i>, clustered by Pfam database.

<p>W = Worker. Q = Queen. Name = Gene name.</p