Send Orders for Reprints to reprints@benthamscience.net MicroRNA, 2020, 9, 1-8 1 REVIEW ARTICLE 2211-5366/20 $58.00+.00 © 2020 Bentham Science Publishers Neglected Tropical Diseases: The Potential Application of microRNAs for Monitoring NTDs in the Real World Supat Chamnanchanunt 1,* , Saovaros Svasti 2 , Suthat Fucharoen 2 and Tsukuru Umemura 3,4 1 Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; 2 Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand; 3 Department of Medical Technology and Sciences, International University of Health and Welfare, Ohkawa, Japan; 4 Department of Clinical Laboratory, Kouhoukai Takagi Hospital, Fukuoka, Japan Abstract: Neglected tropical diseases (NTDs) are a common health problem and require an efficient campaign to be eradicated from tropical countries. Almost a million people die of NTDs every year in the world, and almost forty percent of the patients are under 20 years. Mass drug administration (MDA) is an effective tool for eradication of this health condition. However, a monitoring system is required to evaluate treatment-response and early detection of the re-emerging NTD. The relevance of current tests depends on good quality of the specimen. Thus, new molecular methods with high sensitivity and specificity are required. In this review, we focus on microRNAs (miRNAs) as biomarkers of NTDs through a narrative review on human research. We searched for reliable search engines using a systematical literature review algorithm and included studies that fit the criterion. Five NTDs (lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted helminthiases, and trachoma) were set as our target diseases. Later on, the data were extracted and classified as monitoring response and early detection. Four miRNAs were studied in filariasis as a monitoring response. There were 12 miRNAs related to onchocerciasis infection, and 6 miRNAs with schistosomiasis infection. Six miRNAs showed a link to soil-transmitted helminths. Only 3 miRNAs correlated with trachoma infection. In conclusion, circulating miR is a less invasive and promising approach to evaluate NTDs. Further field study may translate those candidate miRs to clinical application of the prevention and control of NTDs. A R T I C L E H I S T O R Y Received: December 25, 2018 Revised: March 11, 2019 Accepted: May 20, 2019 DOI: 10.2174/2211536608666190620104308 Keywords: Clinical application, lymphatic filariasis, microRNAs, neglected tropical diseases, onchocerciasis, schistosomiasis, soil-transmitted helminthiases, trachoma. 1. NEGLECTED PARASITIC DISEASES The concept of NTDs describes a group of tropical parasitic infections presenting the following characteristics: they predominantly affect poverty-stricken class and manifest in tropical or subtropical regions of countries lacking political attention at national and international levels [1, 2]. NTDs are considered a stigma due to social and economic burden. Among the NTDs, the diseases which do not receive a cure from any advancements in treatment in the field of biotechnology and pharmaceutical, are subjected to elimination protocols through control and prevention. NTDs include the three common diseases of poverty (DOP) (malaria, tuberculosis, and HIV/AIDS) and the five preventive-chemotherapy NTDs (that include, lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted *Address correspondence to this author at the Department of Clinical Tropi- cal Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Tel: +6681-863-9151; Fax: +662-643-5599; E-mail: supat.cha@mahidol.edu helminthiases, and trachoma) [3]. New interventions (both mass drug administration (MDA) and laboratory interven- tions) are required to eliminate and control NTDs. This ap- proach might have a significant benefit, but it needs long- term evaluation of the drugs for their possible curable effects and side-effects [4]. Early laboratory detection is key to monitoring re-emergence and drug-resistance of preventive chemotherapy of NTDs. Thus, the fight against NTDs needs to new investigations, especially on molecular laboratory techniques. 2. MICRORNAS IN TROPICAL DISEASES The microRNAs (miRNAs) gene belongs to the non- coding region, and it consists of small nucleotides (length of 18-25 single-strand RNA). The miRNAs gene is first transcribed to primary miRNAs (pri-miRNAs). The enzyme, Drosha digests pri-miRNAs to produce precursor miRNAs (pre-miRNAs) with lengths between 45 and 140 nt. Pre- miRNAs are made to move from the nucleus to the cytosol