Editorial: Recent Advances in "Omics" of Tropical Diseases

MARCELO A. SOARES ^1* Gustavo Kijak ^2*

• ¹ National Cancer Institute (INCA), Rio de Janeiro, Brazil
• ² AstraZeneca (United States), Wilmington, Delaware, United States

Over the past two decades, technological and computational advances in big biological data have enabled a revolution in our understanding of diverse diseases. Starting with genomics, where whole genome sequences are determined for infectious agents and their hosts, now all types of biological sources can generate global data. Transcriptomes, methylomes, immunomes, metabolomes, lipidomes and microbiomes are commonly generated and assessed for establishing correlates of disease states, both for non-communicable and communicable conditions. Infectious diseases have been intensively studied in this regard, and systems biology has allowed us to understand the molecular mechanisms driving disease in greater detail (1). Direct application of this knowledge has also led to the real-time identification of new pathogens and the rapid design of new vaccines.Infectious diseases of great impact such as HIV/AIDS, influenza and more recently COVID-19 have drawn great attention of the research community due mainly to their established or potential pandemic impact (2). Research groups have assessed those diseases by "omics" techniques, and substantial advances to their mitigation have been achieved. On the other hand, infectious diseases that disproportionately affect low-income countries and parts of the world have been somewhat neglected in those kinds of studies until recently (3), because "omic"-wide studies were expensive and did not occur in developed countries that possess most of the research infrastructure and resources. That is the case of tropical diseases. Recently, with the decreasing costs of the "omics" experimental approaches, and the dissemination of tropical diseases to temperate regions due to the global warming phenomenon, both middle and high-income countries have invested into the research of those diseases.In this Special Issue of Frontiers in Tropical Diseases, we have assembled four different studies (and a corrigendum for one of them) that applied distinct "omics" techniques to diverse diseases, advancing the knowledge on understanding and fighting them. The studies also came from different parts of the world, and included bacteria, viruses, and parasites, thus corroborating the disseminated interest on the subject.In the study "Microbial RNA: The new PAMP of many faces (4), Milillo, Velásquez & Barrionuevo have addressed and reviewed the many different aspects of bacterial RNA, not only limited to triggering pro-inflammatory immune responses, but also capable of inducing down-modulatory responses, which are used by pathogens as an immune evasion mechanism. Bacterial RNAs are part of what the authors call vita-PAMPs, i.e. pathogen-associated molecular patterns linked to the viability of the pathogen. Bacteria like Escherichia coli, Streptococcus pyogenes and Klebsiella pneumonia, and viruses such as HIV and HCV, can all produce RNAs in the cytosol of infected cells which induce down-modulation of MHC-I and II, as well as TLR-7/8 from the cell surface to protect them from recognition and killing.In the second study, "From helping to regulating -A transcriptomic profile of Ifng + Il10 + Il21 + Cd4 + Th1 cells indicates their role in regulating inflammation during experimental trypanosomosis" (5), Nguyen and colleagues discuss the role of CD4+ Th1 cells during experimental Trypanosoma evansi infection in mouse model. Through the use of a modern transcriptomic technique of single cells (scRNA-seq), the author found that this cell subset, highly found during infection, rather than "helping" the immune inflammatory response, provides an anti-inflammatory response by producing high levels of IL-10, an anti-inflammatory cytokine. This regulatory response is likely to dampening inflammation during T.evansi infection. The corrigendum to this study (6) has not changed any of the results or conclusions found, but it was rather related to data availability.The third study, "Challenges and opportunities of molecular epidemiology: usingomics to address complex One Health issues in tropical settings" (7), provides a comprehensive review on the different "omics" techniques and how they can be used for molecular epidemiology studies in One Health approaches. Through a collaboration among authors from three distinct countries (U.S.A., Brazil and Ethiopia), the review uses the two developing countries as models to identify gaps and opportunities for such approaches. The authors highlight capacity building in tropical areas as a need of utmost importance to establish global health.Finally, in the fourth study ("Beyond surveillance: leveraging the potential of next generation sequencing in clinical virology") (8), Aulicino and Kimata provide a perspective on the use of the infrastructure and capacity building in NGS and bioinformatics that took place during the COVID-19 pandemics for future applications in molecular virology. The authors highlight a scale back of those efforts after the end of the pandemics, and despite the use of the structure for other health problems worldwide, they call for the importance of keeping viral surveillance conducted in this setting for managing diagnosis of viral infections and devising treatment options.The field of tropical diseases is provided expanding opportunities to develop in view of current lower-cost experimental procedures and equipment platforms, a growth in bioinformatics hardware, software and human resources, and the expanding geographic dissemination of tropical infectious agents worldwide. Such opportunities should not be neglected so the field is brought back to the spotlight of quality hardcore science.