Arboviral diseases in the Western Brazilian Amazon: a perspective and analysis from a tertiary health & research center in Manaus, State of Amazonas

The Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), located in Manaus, the capital of the State of Amazonas (Western Brazilian Amazon), is a pioneering institution in this region regarding the syndromic surveillance of acute febrile illness, including arboviral infections. Based on the data from patients at the FMT-HVD, we have detected recurrent outbreaks in Manaus by the four dengue serotypes in the past 15 years, with increasing severity of the disease. This endemicity has culminated in the simultaneous circulation of all four serotypes in 2011, the first time this has been reported in Brazil. Between 1996 and 2009, 42 cases of yellow fever (YF) were registered in the State of Amazonas, and 71.4% (30/42) were fatal. Since 2010, no cases have been reported. Because the introduction of the yellow fever virus into a large city such as Manaus, which is widely infested by Aedes mosquitoes, may pose a real risk of a yellow fever outbreak, efforts to maintain an appropriate immunization policy for the populace are critical. Manaus has also suffered silent outbreaks of Mayaro and Oropouche fevers lately, most of which were misdiagnosed as dengue fever. The tropical conditions of the State of Amazonas favor the existence of other arboviruses capable of producing human disease. Under this real threat, represented by at least 4 arboviruses producing human infections in Manaus and in other neighboring countries, it is important to develop an efficient public health surveillance strategy, including laboratories that are able to make proper diagnoses of arboviruses.

Gene Expression Regulation by Agonist-Independent Constitutive Signaling of Melanocortin-1 Receptor

BACKGROUND: Melanocortin-1 receptor (Mc1r), a key signaling receptor for melanogenesis, has been reported to mediate migration of B16F10 melanoma cells. Interestingly, this activity appears to be a part of the constitutive signaling of Mc1r. METHODS: We carried out small interfering RNA-mediated knock-down of Mc1r on murine melanoma B16F10 cells and performed microarray analysis to characterize changes in the gene expression profile. RESULTS: We isolated 22 and four genes whose expression decreased and increased, respectively, by 2.5-fold or higher as the result of Mc1r knock-down. Several down-regulated genes have been proposed to be involved in cell migration. Among these genes are several members of the chemokine gene family. CONCLUSION: We provide a gene set for further functional analyses of Mc1r. The Mc1r target genes we present may be particularly relevant for understanding the ligand-independent activity of Mc1r. Further examination of the mode of action may lead to novel strategies in regulating the migration and metastasis of melanoma cells.

Mechanisms regulating melanogenesis* / Mecanismos reguladores da melanogênese

Skin pigmentation is an important human phenotypic trait whose regulation, in spite of recent advances, has not yet been fully understood. The pigment melanin is produced in melanosomes by melanocytes in a complex process called melanogenesis. The melanocyte interacts with endocrine, immune, inflammatory and central nervous systems, and its activity is also regulated by extrinsic factors such as ultraviolet radiation and drugs. We have carried out a review of the current understanding of intrinsic and extrinsic factors regulating skin pigmentation, the melanogenesis stages and related gene defects. We focused on melanocyte-keratinocyte interaction, activation of melanocortin type 1 receptor (MC1-R) by peptides (melanocyte-stimulating hormone and adrenocorticotropic hormone) resulting from proopiomelanocortin (POMC) cleavage, and mechanisms of ultraviolet-induced skin pigmentation. The identification and comprehension of the melanogenesis mechanism facilitate the understanding of the pathogenesis of pigmentation disorders and the development of potential therapeutic options.

A pigmentação da pele é um importante traço fenotípico do ser humano mas apesar dos recentes avanços a sua regulação não está ainda totalmente esclarecida. O pigmento melanina é produzido nos melanossomas pelos melanócitos, num processo complexo designado por melanogénese. O melanócito interatua com os sistemas endócrino, imunitário, inflamatório e nervoso central e a sua atividade é também regulada por fatores extrínsecos como a radiação ultravioleta e fármacos. Fizemos uma revisão do conhecimento atual sobre os fatores intrínsecos e extrínsecos reguladores da pigmentação cutânea, etapas da melanogénese e defeitos genéticos relacionados. Fizemos enfoque na interação melanócito-keratinócito, na ativação do receptor da melanocortina tipo 1 (MC1-R) pelos péptidos (hormona estimuladora do melanócito e hormona adrenocorticotrófica) resultantes da clivagem da proopiomelanocortina (POMC) e mecanismos da pigmentação induzida pela radiação ultravioleta. A identificação e compreensão dos mecanismos reguladores da pigmentação cutânea facilitam o conhecimento dos mecanismos patogénicos dos distúrbios da pigmentação e o desenvolvimento de potenciais opções terapêuticas.

Association study of MC1R gene polymorphisms with freckles in Chinese Han population from Chengdu / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the association between single nucleotide polymorphisms (SNPs) of melanocortin-1 receptor gene (MC1R) and freckles in Chinese Han population from Chengdu.</p><p><b>METHODS</b>Twenty randomly selected samples were used to select SNPs of the MC1R gene through DNA sequencing. Pyrosequencing in combination with DNA pooling technique was used to assess allelic frequencies of the selected SNPs in 111 individuals with freckles and 124 normal controls. Representative SNPs were selected based on their functional implications and minimum allele frequency (MAF> 0.05). Genotype of the SNPs were determined with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) or pyrosequencing.</p><p><b>RESULTS</b>Based on results of DNA sequencing and pyrosequencing, 4 SNPs (rs2228479, rs885479, rs33932559 and rs2228478) were selected to determine the genotype for each sample. Comparison of genotypic and allelic frequencies of the 4 SNPs with χ (2) test has found no significant difference between the two groups (P> 0.05). For rs33932559, the frequencies of T allele were respectively 90.09% and 91.94% for individuals with freckles and normal controls. For rs2228479 and rs2228478, the frequencies of G and A allele were both about 77%. For rs885479, the frequency of T allele was about 60%. None of the above 3 SNPs showed a significant difference between the two groups in terms of allelic or genotypic frequencies.</p><p><b>CONCLUSION</b>No association between the selected SNPs of MC1R gene has been found with development of freckles for the selected Chinese Han population from Chengdu.</p>

Sequence variation in the melanocortin-1 receptor (MC1R) pigmentation gene and its role in the cryptic coloration of two South American sand lizards

In reptiles, dorsal body darkness often varies with substrate color or temperature environment, and is generally presumed to be an adaptation for crypsis or thermoregulation. However, the genetic basis of pigmentation is poorly known in this group. In this study we analyzed the coding region of the melanocortin-1-receptor (MC1R) gene, and therefore its role underlying the dorsal color variation in two sympatric species of sand lizards (Liolaemus) that inhabit the southeastern coast of South America: L. occipitalis and L. arambarensis. The first is light-colored and occupies aeolic pale sand dunes, while the second is brownish and lives in a darker sandy habitat. We sequenced 630 base pairs of MC1R in both species. In total, 12 nucleotide polymorphisms were observed, and four amino acid replacement sites, but none of them could be associated with a color pattern. Comparative analysis indicated that these taxa are monomorphic for amino acid sites that were previously identified as functionally important in other reptiles. Thus, our results indicate that MC1R is not involved in the pigmentation pattern observed in Liolaemus lizards. Therefore, structural differences in other genes, such as ASIP, or variation in regulatory regions of MC1R may be responsible for this variation. Alternatively, the phenotypic differences observed might be a consequence of non-genetic factors, such as thermoregulatory mechanisms.

Detection of binding activity and biologic effect of a novel alpha-melanocyte-stimulating hormone analogue / 药学学报

Binding activity and biologic effect of a novel alpha-melanocyte-stimulating hormone analogue were tested on cells transiently expressing the human melanocortin-1 (MC1), MC3, MC4, and MC5 receptors. The human MC1 and MC5 receptor genes were cloned into the expression vector pcDNA3. 1/ myc-his(-) B. The vectors were transferred to HEK-293 cells by the calcium phosphate method. Stable receptor populations were generated using G418 selection (900 microg x mL(-1)) for subsequent bioassay analysis. K(i) values of the novel alpha-MSH analogue for MC1, MC3, MC4, and MC5 receptors were obtained in competition with [125I]-NDP-MSH for binding studies. The cyclic AMP level was tested by using [3H]-cyclic AMP kit. It is showed that K(i) values of the novel alpha-MSH analogue for MC1, MC3, MC4, and MC5 receptors were (0.159 +/- 0.040), (35.430 +/- 6.743), (19.293 +/- 2.780) and (2.230 +/- 0.670) nmol L(-1), respectively. Its EC50 values for MC1, MC3, MC4, and MC5 receptors were (0.45 +/- 0.07), (7.80 +/- 0.65), (2.55 +/- 0.23) and (0.33 +/- 0.09) nmol L(-1), respectively. In these tests, the novel alpha-MSH analogue is a MC1R and MC5R selective agonist.

cDNA Microarray Analysis of Differential Gene Expression in Gastric Cancer Cells Sensitive and Resistant to 5-Fluorouracil and Cisplatin / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Gastric cancer is one of the most prevalent cancers worldwide. 5-fluorouracil (5-FU) and cisplatin are the most commonly used drugs for the treatment of gastric cancer. However, a significant number of tumors often fail to respond to chemotherapy. MATERIALS AND METHODS: To better understand the molecular mechanisms underlying drug resistance in gastric cancer the gene expression in gastric cancer cells, which were either sensitive or resistant to 5-FU and cisplatin, were examined using cDNA microarray analysis. To confirm the differential gene expression, as determined using the microarray, semiquantitative RT-PCR was performed on a subset of differentially expressed cDNAs. RESULTS: 69 and 45 genes, which were either up-regulated (9 and 22 genes) or down-regulated (60 and 25 genes), were identified in 5-FU- and cisplatin-resistant cells, respectively. Several genes, such as adaptor-related protein complex 1 and baculoviral IAP repeat-containing 3, were up-regulated in both drug-resistant cell types. Several genes, such as the ras homolog gene family, tropomyosin, tumor rejection antigen, protein disulfide isomerase-related protein, melanocortin 1 receptor, defensin, cyclophilin B, dual specificity phosphatase 8 and hepatocyte nuclear factor 3, were down-regulated in both drug-resistant cell types. CONCLUSION: These findings show that cDNA microarray analysis can be used to obtain gene expression profiles that reflect the effect of anticancer drugs on gastric cancer cells. Such data may lead to the assigning of signature expression profiles of drug-resistant tumors, which may help predict responses to drugs and assist in the design of tailored therapeutic regimens to overcome drug resistance.

The Expression of the alpha-Melanocyte Stimulating Hormone (alpha-MSH) and Melanocortin-1 Receptor (MC1R) in the Epidermis of the Vitiligo / 대한피부과학회지

BACKGROUND: Vitiligo is a skin disease that is characterized by the loss of cutaneous pigmentation. alpha-Melanocyte stimulating hormone (alpha-MSH) is a neuroimmunomodulating peptide derived from proopiomelanocortin, and melanocortin-1 receptor (MC1R) is a surface receptor which is expressed by several other cutaneous cells including melanocyte and keratinocyte. Both of them have been known to be the main physiologic regulator for integumental pigmentation. OBJECTIVE: To evaluate the expression pattern of alpha-MSH and MC1R in the epidermis of vitiligo patients. METHODS: Specimens were obtained in lesional, perilesional and non-lesional skin in 10 patients with vitiligo and from 3 normal persons by the punch biopsy. And then, indirect immunofluorescence was done to show the pattern of expression of alpha-MSH and MC1R. RESULTS: Pattern of expression between alpha-MSH and MC1R was nearly the same. In vitiligo patients with stable disease state (7 of 10), the expression of alpha-MSH and MC1R in the non-lesional skin was more prominent than that in lesional area. In vitiligo patients with active disease state (3 of 10), the expression of alpha-MSH and MC1R in the lesional skin was more prominent than that in non-lesional area. CONCLUSION: Between the stable and active vitiligo patients, there was a different pattern of expression of alpha-MSH and MC1R in the lesional skin.