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Rhinoceros Serum microRNAs: Identification, Characterization, and Evaluation of Potential Iron Overload Biomarkers
Jessye Wojtusik1, Erin Curry1, Terri L Roth1
1Center for Conservation and Research of Endangered Wildlife (CREW), Cincinnati Zoo and Botanical Garden, Cincinnati, OH, United States.
Abstract:
Iron overload disorder (IOD) in critically endangered Sumatran (Dicerorhinus sumatrensis) and black (Diceros bicornis) rhinoceros is an over-accumulation of iron in organs which may exacerbate other diseases and indicate metabolic disturbances. IOD in rhinos is not well understood and diagnostics and therapeutics are limited in effectiveness. MicroRNAs (miRNAs) are small non-coding RNAs capable of altering protein synthesis. miRNA expression responds to physiological states and could serve as the basis for development of diagnostics and therapeutics. This study aimed to identify miRNAs differentially expressed among healthy rhinos and those afflicted with IOD or other diseases ("unhealthy"), and assess expression of select miRNAs to evaluate their potential as biomarkers of IOD. miRNAs in serum of black (n = 11 samples; five individuals) and Sumatran (n = 7 samples; four individuals) rhinos, representing individuals categorized as healthy (n = 9), unhealthy (n = 5), and afflicted by IOD (n = 3) were sequenced. In total, 715 miRNAs were identified, of which 160 were novel, 131 were specific to black rhinos, and 108 were specific to Sumatran rhinos. Additionally, 95 miRNAs were specific to healthy individuals, 31 specific to unhealthy, and 63 were specific to IOD individuals. Among healthy, unhealthy, and IOD states, 21 miRNAs were differentially expressed (P ≤ 0.01). Five known miRNAs (let-7g, miR-16b, miR-30e, miR-143, and miR-146a) were selected for further assessment via RT-qPCR in serum from black (n = 61 samples; seven individuals) and Sumatran (n = 38 samples; five individuals) rhinos. let-7g, miR-30e, and miR-143 all showed significant increased expression (P ≤ 0.05) during IOD (between 1 and 2 years prior to death) and late IOD (within 1 year of death) compared to healthy and unhealthy individuals. miR-16b expression increased (P ≤ 0.05) in late IOD, but was not different among IOD, healthy, and unhealthy states (P > 0.05). Expression of miR-146a increased in IOD and late IOD as compared to unhealthy samples (P ≤ 0.05) but was not different from the healthy state (P > 0.05). Selected serum miRNAs of black and Sumatran rhinos, in particular let-7g, miR-30e, and miR-143, could therefore provide a tool for advancing rhino IOD diagnostics that should be further investigated.
Insights
Iron overload disorder (IOD) in rhinos can be diagnosed using specific microRNAs (miRNAs) found in serum. let-7g, miR-30e, and miR-143 show promise as biomarkers for early detection of IOD in Sumatran and black rhinoceros.
Area of Science:
- Veterinary Medicine
- Genomics
- Biochemistry
Background:
- Iron overload disorder (IOD) is a serious condition in Sumatran and black rhinoceros, poorly understood with limited diagnostic and therapeutic options.
- MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression and can indicate physiological states, offering potential for diagnostic development.
Purpose of the Study:
- To identify differentially expressed miRNAs in healthy, unhealthy, and IOD-afflicted rhinos.
- To evaluate the potential of specific miRNAs as serum biomarkers for diagnosing IOD in rhinoceros.
Main Methods:
- Serum samples from black and Sumatran rhinos were analyzed using miRNA sequencing to identify expressed miRNAs.
- Quantitative real-time PCR (RT-qPCR) was employed to assess the expression levels of selected miRNAs (let-7g, miR-16b, miR-30e, miR-143, miR-146a) in rhino serum.
Main Results:
- A total of 715 miRNAs were identified, with 160 novel and species-specific miRNAs found for black and Sumatran rhinos.
- Twenty-one miRNAs were found to be differentially expressed among healthy, unhealthy, and IOD states (P ≤ 0.01).
- Serum levels of let-7g, miR-30e, and miR-143 were significantly increased in rhinos with IOD, suggesting their potential as biomarkers.
Conclusions:
- Specific serum miRNAs, particularly let-7g, miR-30e, and miR-143, show potential as diagnostic biomarkers for iron overload disorder in Sumatran and black rhinoceros.
- Further investigation is warranted to validate these miRNAs as reliable tools for advancing rhino IOD diagnostics and management.
