Identification of microRNAs in the Lyme Disease Vector Ixodes scapularis

Abstract

MicroRNAs (miRNAs) are a class of small non-coding RNAs involved in many biological processes, including the immune pathways that control bacterial, parasitic, and viral infections. Pathogens probably modify host miRNAs to facilitate successful infection, so they might be useful targets for vaccination strategies. There are few data on differentially expressed miRNAs in the black-legged tick Ixodes scapularis after infection with Borrelia burgdorferi, the causative agent of Lyme disease in the United States. Small RNA sequencing and qRT-PCR analysis were used to identify and validate differentially expressed I. scapularis salivary miRNAs. Small RNA-seq yielded 133,465,828 (≥18 nucleotides) and 163,852,135 (≥18 nucleotides) small RNA reads from Borrelia-infected and uninfected salivary glands for downstream analysis using the miRDeep2 algorithm. As such, 254 miRNAs were identified across all datasets, 25 of which were high confidence and 51 low confidence known miRNAs. Further, 23 miRNAs were differentially expressed in uninfected and infected salivary glands: 11 were upregulated and 12 were downregulated upon pathogen infection. Gene ontology and network analysis of target genes of differentially expressed miRNAs predicted roles in metabolic, cellular, development, cellular component biogenesis, and biological regulation processes. Several Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, including sphingolipid metabolism; valine, leucine and isoleucine degradation; lipid transport and metabolism; exosome biogenesis and secretion; and phosphate-containing compound metabolic processes, were predicted as targets of differentially expressed miRNAs. A qRT-PCR assay was utilized to validate the differential expression of miRNAs. This study provides new insights into the miRNAs expressed in I. scapularis salivary glands and paves the way for their functional manipulation to prevent or treat B. burgdorferi infection.

Analysis ofAmblyomma americanummicroRNAs in response toEhrlichia chaffeensis infection and their potential role in vectorial capacity

“…RNA was extracted from each tissue using the Trizol method as described previously (Kumar et al, 2022). In a qPCR assay, the E. chaffeensis infection in individual tick tissues was assessed using disulfide bond formation (dsb) gene primers (Dunphy et al, 2014).…”

“…Several omics studies have characterized the time-dependent, tissues-dependent blood-meal and pathogen-induced differential gene expression in variety of tick species (Karim et al, 2011; Karim and Ribeiro 2015; Guizzo et al, 2022; Adegoke et al, 2023; 2024; Anderson et al, 2008; Villar et al, 2015; Antunes et al, 2019; Popara et al, 2015; Bartel, 2004). However, studies addressing the role of pathogens in differentially modulating tick’s small RNAs are limited (Kumar et al, 2022; Artigas-Jerónimo et al, 2019; Hermance et al, 2019; Ramasamy et al, 2020). A handful of studies have investigated how miRNAs regulate the tick-pathogen interaction.…”

“…Understanding the molecular interactions between tick vectors and E. chaffeensis , and the characterization of differentially regulated tick miRNAs are needed to develop new approaches to combat tick-borne infections. Identification of new and novel miRNAs by using new sequencing platforms opened up a new avenue of research (Kumar et al, 2022; Artigas-Jerónimo et al, 2019; Luo et al, 2022). In this work, a small RNA sequencing approach was utilized to identify miRNAs induced by E. chaffeensis in A. americanum tissues, and differentially expressed miRNAs were functionally characterized using a miRNA inhibitor approach.…”

Analysis of Amblyomma americanum microRNAs in response to Ehrlichia chaffeensis infection and their potential role in vectorial capacity

“…Several omics studies have characterized the time-dependent, tissues-dependent blood-meal and pathogen-induced differential gene expression in variety of tick species ( Bartel, 2004 ; Anderson et al., 2008 ; Karim et al., 2011 ; Karim and Ribeiro, 2015 ; Popara et al., 2015 ; Villar et al., 2015 ; Antunes et al., 2019 ; Guizzo et al., 2022 ; Adegoke et al., 2023 , Adegoke et al., 2024 ). However, studies addressing the role of pathogens in differentially modulating tick’s small RNAs are limited ( Artigas-Jerónimo et al., 2019 ; Hermance et al., 2019 ; Ramasamy et al., 2020 ; Kumar et al., 2022 ). A handful of studies have investigated how miRNAs regulate the tick-pathogen interaction.…”

A MicroRNA Profile of the Saliva in the Argasid Ticks Ornithodoros Erraticus and Ornithodoros Moubata and Prediction of Specific Target Genes

“…Some additional studies have examined how miRNAs regulate the tick-pathogen relationship. They have shown that Ixodes scapularis miRNAs facilitate transmission of Anaplasma phagocytophylum, Borrelia burgdorferi sensu stricto and Powassan virus, and thus helping to establish the infection (Artigas-Jerónimo et al, 2019;Hermance et al, 2019;Ramasamy et al, 2020;Kumar et al, 2022). Apart from these studies, only one has investigated tick miRNA-mediated regulation of vertebrate host gene expression at the tick-host interface (Hackenberg et al, 2017).…”