microRNA Function Research Articles

EXTH-31. TARGETINGMIR-19B/PPP2R5E REGULATORY AXIS TO MAXIMISE ALKYLATING AGENT EFFICACY: A NEW AVENUE TO COUNTERACT TEMOZOLOMIDE RESISTANCE IN RECURRENT GLIOBLASTOMAS

Abstract Glioblastoma, IDH-wildtype (GBM), notorious for its inevitable recurrence despite aggressive multi-modal standard of care, presents a pressing need for novel treatment paradigms. The extensive DNA damage caused by the frontline DNA alkylating agent, temozolomide (TMZ) is counteracted by intricate or acquired survival mechanisms. Through functional microRNA screens we identified miR-19b-overexpressing clones possessing extra fitness in presence of escalating doses of TMZ. Our study uncovers a previously unrecognized TMZ resistance mechanism governed by miR-19b. Notably, miR-19b attenuation intensified DNA damage response and CHEK1 and CHEK2 phosphorylation, instigating persistent DNA lesions and consequently priming GBM cells for heightened TMZ cytotoxicity. Mechanistically, we showed that miR-19b exerts its function by targeting PPP2R5E, a subunit of protein phosphatase PP2A, frequently downregulated in GBM. We uncovered that the elevated DNA damage response in the miR-19b-attenuated cells was a consequence of enhanced nuclear and mitochondrial ROS production. This in turn, induced ROS-mediated senescence, and an intriguing susceptibility to ferroptosis, possibly due to increased ROS-mediated lipid peroxidation. Of note, all these phenotypes were reversed in GBM cells with concomitant miR-19b and PPP2R5E attenuation, demonstrating that miR-19b exerts its role in TMZ resistance by targeting PPP2R5E. In line with this finding, an orthotopic human-derived glioblastoma stem cell xenograft model confirmed that PPP2R5E attenuation not only decreases TMZ cytotoxicity in the brain, but also at the spinal metastatic location. Consistently, treating cells with the PP2A-activating drug FTY720 or knocking down endogenous PP2A-inhibiting proteins mirrored the effects of miR-19b attenuation in enhancing TMZ cytotoxicity. This intricate interplay between miR-19b and PPP2R5E underscores a novel strategy to modulate the TMZ response, highlighting promising results in our pre-clinical models. In conclusion, our findings advocate for the therapeutic targeting of the miR-19b/PPP2R5E regulatory axis as a potential novel strategy in the pursuit of effective therapeutic interventions for the formidable recurrent GBM tumours.

Can miRNAs in MSCs-EVs Offer a Potential Treatment for Hypoxic-ischemic Encephalopathy?

Neonatal hypoxic-ischemic encephalopathy (HIE) is a critical condition resulting from impaired oxygen and blood flow to the brain during birth, leading to neuroinflammation, neuronal apoptosis, and long-term neurological deficits. Despite the use of therapeutic hypothermia, current treatments remain inadequate in fully preventing brain damage. Recent advances in mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) offer a novel, cell-free therapeutic approach, as these EVs can cross the blood-brain barrier (BBB) and deliver functional microRNAs (miRNAs) to modulate key pathways involved in inflammation and neuroprotection. This review examines how specific miRNAs encapsulated in MSC-EVs-including miR-21, miR-124, miR-146, and the miR-17-92 cluster-target the complex inflammatory responses that drive HIE pathology. By modulating pathways such as NF-κB, STAT3, and PI3K/Akt, these miRNAs influence neuroinflammatory processes, reduce neuronal apoptosis, and promote tissue repair. The aim is to assess the therapeutic potential of miRNA-loaded MSC-EVs in mitigating inflammation and neuronal damage, thus addressing the limitations of current therapies like therapeutic hypothermia.

Identifying the function of novel cross-species microRNAs from the excretory-secretory products of Angiostrongylus cantonensis fifth-stage larvae

Identifying the function of novel cross-species microRNAs from the excretory-secretory products of Angiostrongylus cantonensis fifth-stage larvae

SChemNET: a deep learning framework for predicting small molecules targeting microRNA function

MicroRNAs (miRNAs) have been implicated in human disorders, from cancers to infectious diseases. Targeting miRNAs or their target genes with small molecules offers opportunities to modulate dysregulated cellular processes linked to diseases. Yet, predicting small molecules associated with miRNAs remains challenging due to the small size of small molecule-miRNA datasets. Herein, we develop a generalized deep learning framework, sChemNET, for predicting small molecules affecting miRNA bioactivity based on chemical structure and sequence information. sChemNET overcomes the limitation of sparse chemical information by an objective function that allows the neural network to learn chemical space from a large body of chemical structures yet unknown to affect miRNAs. We experimentally validated small molecules predicted to act on miR-451 or its targets and tested their role in erythrocyte maturation during zebrafish embryogenesis. We also tested small molecules targeting the miR-181 network and other miRNAs using in-vitro and in-vivo experiments. We demonstrate that our machine-learning framework can predict bioactive small molecules targeting miRNAs or their targets in humans and other mammalian organisms.

MiR-224-5p alleviates preeclampsia-like mouse symptoms by targeting PANX1 to inhibit ferroptosis in trophoblast cells

Preeclampsia (PE) is a high morbidity and lethality disease specific to pregnancy, and insufficient placental trophoblast invasion acts as a crucial factor contributing to PE development. The present study investigated the function and potential mechanism of microRNA (miR)-224-5p within PE. In the study, miR-224-5p expression was reduced within placental tissue samples of the PE mouse model and PE cell model. Restoration of miR-224-5p expression markedly inhibited ROS levels and ferroptosis, lowered blood pressure in pregnant mice, increased the live birth rate, and enhanced trophoblast cell proliferation and invasion as well as suppressed their apoptosis. miR-224-5p could target and suppress PANX1, and overexpression of PANX1 could significantly advance ferroptosis and cause trophoblast dysfunction, a process that might be relieved via restoring miR-224-5p expression. In conclusion, miR-224-5p/PANX1 ameliorates trophoblast dysfunction by inhibiting ferroptosis, which provides a potential new option for clinical treatment of PE.

The Role of MicroRNAs and Stem cells in Rheumatoid Arthritis: A Therapeutic and Diagnostic Approach.

In autoimmune illnesses like Rheumatoid Arthritis (RA), the synovium is constantly inflamed, and joints are ruptured. It is becoming increasingly clear that stem cells, especially notably mesenchymal stem cells (MSCs) and microRNAs (miRNAs), play important roles in the onset and amelioration of RA. There is mounting evidence from both animal and human studies that suggests a potentially safe and effective method to treat RA and other intractable diseases by reducing chronic inflammation and spurring tissue regeneration through the transplantation of multipotent adult stem cells, such as mesenchymal stromal/stem cells. To control gene expression, which impacts immune cell differentiation and inflammatory pathways, microRNAs (miRNAs) are crucial, even though MSCs can self-renew and modify inflammatory reactions. The pathophysiology of RA is marked by the dysregulation of immunological responses and the proliferation of fibroblast-like synoviocytes, which are linked to the aberrant expression of specific microRNAs (miRNAs). This study mainly aims to examine the therapeutic implications of these microRNAs (miRNAs) in relation to RA, as they can function as diagnostic and prognostic indicators. This study explores the functions of microRNAs (miRNAs) and stem cells in rheumatoid arthritis (RA), drawing attention to the relevance of these biological processes and the potential for creating novel therapeutic strategies to improve patient outcomes.

Identification and function of microRNAs in hemipteran pests: A review.

Hemiptera is one of the most significant orders of insect pests, including whiteflies, true bugs, aphids, planthoppers, psyllids, and so forth, which have led to substantial economic losses in agricultural industries and have significantly affected food yields through their ability to suck the phloem sap of crops and transmit numerous bacterial and viral pathogens. Therefore, explorations of pest-specific, eco-friendly and easy-to-adopt technologies for hemipteran pest control are urgently needed. To the best of our knowledge, microRNAs (miRNAs), which are endogenous non-coding small RNAs approximately 22 nucleotides in length, are involved in regulating gene expression via the direct recognition and binding of the 3'-untranslated region (3'-UTR) of target messenger RNAs (mRNAs) or by acting as a center of a competitive endogenous RNA (ceRNA) network at the post-transcriptional level. This review systematically outlines the characterization and functional investigation of the miRNA biogenesis pathway in hemipteran pests, such as whiteflies, true bugs, aphids and planthoppers. In addition, we explored the results of small RNA sequencing and functional observations of miRNAs in these pests, and the results suggest that the numerous miRNAs obtained and annotated via high-throughput sequencing technology and bioinformatic analyses contribute to molting development, fitness, wing polyphenism, symbiont interactions and insecticide resistance in hemipteran pests. Finally, we summarize current advances and propose a framework for future research to extend the current data and address potential limitations in the investigation and application of hemipteran miRNAs.

The Integrated Analysis of miRNome and Degradome Sequencing Reveals the Regulatory Mechanisms of Seed Development and Oil Biosynthesis in Pecan (Carya illinoinensis).

Pecan seed oil is a valuable source of essential fatty acids and various bioactive compounds; however, the functions of microRNAs and their targets in oil biosynthesis during seed development are still unknown. Here, we found that the oil content increased rapidly in the three early stages in three cultivars, and that oleic acid was the predominant fatty acid component in the mature pecan embryos. We identified, analyzed, and validated the expression levels of miRNAs related to seed development and oil biosynthesis, as well as their potential target genes, using small RNA sequencing data from three stages (120, 135, and 150 days after flowering). During the seed development process, 365 known and 321 novel miRNAs were discovered. In total, 91 known and 181 novel miRNAs were found to be differentially expressed, and 633 target genes were further investigated. The expression trend analysis revealed that the 91 known miRNAs were classified into eight groups, approximately two-thirds of which were up-regulated, whereas most novel miRNAs were down-regulated. The qRT-PCR and degradome sequencing data were used to identify five miRNA- target pairs. Overall, our study provides valuable insights into the molecular regulation of oil biosynthesis in pecan seeds.

Transcriptome-Wide Evaluation Characterization of microRNAs and Assessment of Their Functional Roles as Regulators of Diapause in Ostrinia furnacalis Larvae (Lepidoptera: Crambidae).

microRNAs (miRNAs) function as vital regulators of diapause in insects through their ability to post-transcriptionally suppress target gene expression. In this study, the miRNA of Ostrinia furnacalis, an economically important global crop pest species, was characterized. For the included analyses, 9 small RNA libraries were constructed using O. furnacalis larvae in different diapause states (non-diapause, ND; diapause, D; diapause-termination, DT). The results identified 583 total miRNAs, of which 256 had previously been identified, whereas 327 were novel. Furthermore, comparison analysis revealed that 119 and 27 miRNAs were differentially expressed in the D vs. ND and DT vs. D, respectively. Moreover, the expression patterns of their miRNAs were also analyzed. GO and KEGG analysis of the target genes of differentially expressed miRNAs highlighted the importance of these miRNAs as diapause regulators in O. furnacalis, especially through metabolic processes, endocrine processes, 20-hydroxyecdysone, and circadian clock signaling pathways. In summary, this study highlighted the involvement of specific miRNAs in the control of diapause in O. furnacalis. To the best of our knowledge, this is the first study to identify miRNA expression patterns in O. furnacalis, thereby providing reference and novel evidence enhancing our current understanding of how small RNAs influence insect diapause.

Identification and characterization of functional microRNAs and their significant targets in maize plants

Identification and characterization of functional microRNAs and their significant targets in maize plants

Characterization and functions of temperature stress-associated microRNAs in invasive insect Bemisia tabaci Mediterranean cryptic species

With the development of international trade and frequent personnel exchanges, biological invasion is showing a rapidly growing trend worldwide. Insects are ectothermic animals, so their geographical distribution is due largely to their high and low temperature tolerances. To study the temperature response mechanisms of Bemisia tabaci MED cryptic species, miRNA-seq technology was used to unravel the miRNA library of B. tabaci MED in three field populations (TP, HB, and HK) from cities with different environmental temperatures. We identified 12 differentially expressed miRNAs in response to temperature stress, and Bta-miR-998 and Bta-miR-129 were shown to be associated with temperature tolerance. In addition, we predicted and verified the target genes associated with the temperature tolerance imparted by Bta-miR-998 and Bta-miR-129. The results showed that the down-regulated target gene of Bta-miR-129, BtMGAT3, significantly reduced the heat tolerance and another down-regulated target gene, BtRGS7, affected the cold tolerance of B. tabaci MED. These results indicate that gene expression regulated by miRNAs is an important temperature response mechanism in B. tabaci MED. This study reveals the important regulatory role of miRNA in insect temperature adaptation and provides a new avenue for studying the regulation of insect gene expression by miRNA.

Effects of Scutellaria baicalensis Extract-Induced Exosomes on the Periodontal Stem Cells and Immune Cells under Fine Dust.

In adverse environments, fine dust is linked to a variety of health disorders, including cancers, cardiovascular, neurological, renal, reproductive, motor, systemic, and respiratory diseases. Although PM10 is associated with oral inflammation and cancer, there is limited research on biomaterials that prevent damage caused by fine dust. In this study, we evaluated the effects of biomaterials using microRNA profiling, flow cytometry, conventional PCR, immunocytochemistry, Alizarin O staining, and ELISA. Compared to SBE (Scutellaria baicalensis extract), the preventive effectiveness of SBEIEs (SBE-induced exosomes) against fine dust was approximately two times higher. Furthermore, SBEIEs promoted cellular differentiation of periodontal ligament stem cells (PDLSCs) into osteoblasts, periodontal ligament cells (PDLCs), and pulp progenitor cells (PPCs), enhancing immune modulation for oral health against fine dust. In terms of immune modulation, SBEIEs activated the secretion of cytokines such as IL-10, LL-37, and TGF-β in T cells, B cells, and macrophages, while attenuating the secretion of MCP-1 in macrophages. MicroRNA profiling revealed that significantly modulated miRNAs in SBEIEs influenced four biochemical categories: apoptosis, cellular differentiation, immune activation, and anti-inflammation. These findings suggest that SBEIEs are an optimal biomaterial for developing oral health care products. Additionally, this study proposes functional microRNA candidates for the development of pharmaceutical liposomes.

AAV-Mediated Expression of miR-17 Enhances Neurite and Axon Regeneration In Vitro.

Neurodegenerative disorders, including traumatic injuries to the central nervous system (CNS) and neurodegenerative diseases, are characterized by early axonal damage, which does not regenerate in the adult mammalian CNS, leading to permanent neurological deficits. One of the primary causes of the loss of regenerative ability is thought to be a developmental decline in neurons' intrinsic capability for axon growth. Different molecules are involved in the developmental loss of the ability for axon regeneration, including many transcription factors. However, the function of microRNAs (miRNAs), which are also modulators of gene expression, in axon re-growth is still unclear. Among the various miRNAs recently identified with roles in the CNS, miR-17, which is highly expressed during early development, emerges as a promising target to promote axon regeneration. Here, we used adeno-associated viral (AAV) vectors to overexpress miR-17 (AAV.miR-17) in primary cortical neurons and evaluate its effects on neurite and axon regeneration in vitro. Although AAV.miR-17 had no significant effect on neurite outgrowth and arborization, it significantly enhances neurite regeneration after scratch lesion and axon regeneration after axotomy of neurons cultured in microfluidic chambers. Target prediction and functional annotation analyses suggest that miR-17 regulates gene expression associated with autophagy and cell metabolism. Our findings suggest that miR-17 promotes regenerative response and thus could mitigate neurodegenerative effects.

Small Differences and Big Changes: The Many Variables of MicroRNA Expression and Function in the Brain.

MicroRNAs are emerging as crucial regulators within the complex, dynamic environment of the synapse, and they offer a promising new avenue for the treatment of neurological disease. These small noncoding RNAs modify gene expression in several ways, including posttranscriptional modulation via binding to complementary and semicomplementary sites on target mRNAs. This rapid, finely tuned regulation of gene expression is essential to meet the dynamic demands of the synapse. Here, we provide a detailed review of the multifaceted world of synaptic microRNA regulation. We discuss the many mechanisms by which microRNAs regulate gene expression at the synapse, particularly in the context of neuronal plasticity. We also describe the various factors, such as age, sex, and neurological disease, that can influence microRNA expression and activity in neurons. In summary, microRNAs play a crucial role in the intricate and quickly changing functional requirements of the synapse, and context is essential in the study of microRNAs and their potential therapeutic applications.

Abstract Tu001: MiR-21 mitigated pulmonary hypertension induced right ventricular dysfunction through pulmonary circulating exosomes

Background: Patients with pulmonary arterial hypertension (PAH) often experience adverse outcomes primarily due to right ventricular (RV) dysfunction. However, the intricate relationship between pulmonary circulation and RV remodeling remains largely unexplored. Exosomal microRNAs (miRNAs) function as paracrine signaling mediators in diverse diseases. Aims: To investigate the ability of exosomal miRNAs derived from pulmonary endothelial cells to transmit signals affecting cardiomyocytes. Methods and Results: Utilizing next-generation sequencing, we identified several target miRNAs by analyzing exosome samples obtained through right-heart catheterization. Notably, exosomal miR-21 exhibited the highest expression in the pulmonary circulation (Figure 1) . Under hypoxic conditions, the expression of miR-21 increased in human pulmonary endothelial cells (HPECs) and in exosomes derived from their conditioned medium. Treatment with these exosomes enhanced miR-21 expression and concurrently mitigated apoptosis in hypoxia-exposed cardiomyocytes. Likewise, miR-21 demonstrated a protective role against hypoxia-induced injuries and apoptosis, involving the SPRY-2/p-ERK and PTEN/Akt pathways. In a murine model of sugen/hypoxia-induced PAH, mice lacking miR-21 (miR-21 -/- ) exhibited more severe RV dysfunction, altered hemodynamics, and increased fibrosis compared to wild-type (WT) mice. Employing a parabiosis model, pairs consisting of WT and miR-21 -/- mice were shielded from RV dysfunction, whereas pairs of miR-21 -/- mice displayed exacerbated RV function (Figure 2) . Conclusion: Hypoxia stimulates the production of exosomal miR-21 in both HPECs and their microenvironment, subsequently mitigating apoptosis in cardiomyocytes (Figure 3) . Our findings propose endothelial cell-derived exosomal miR-21 as a promising therapeutic target for PAH.

Circ_0002722-induced regulation of YAP promotes platinum resistance in oral squamous cell carcinoma: Implications for verteporfin therapy

Oral squamous cell carcinoma (OSCC) poses a significant public health burden due to its high prevalence and poor prognosis. Platinum resistance is one of the major challenges in OSCC treatment. Yes-associated protein (YAP) has been identified as a pivotal player in OSCC tumorigenesis and progression. Circular RNA (circRNA) has been implicated in chemoresistance in various cancers by regulation the function of microRNA. Nevertheless, the specific mechanisms linking circRNA to YAP expression in OSCC remain poorly understood. In this study, we detected the YAP and circRNA hsa_circ_0002722 (circ_0002722) expression by western blot (WB) and quantitative polymerase chain reaction (qPCR). We found that YAP and circ_0002722 were up-regulated in platinum resistance in OSCC tissues. Furthermore, transfection of circ_0002722 siRNA into platinum-resistant cells revealed that circ_0002722 acted as a regulator of miR-1305, which influenced YAP expression and thereby affected platinum sensitivity. In vivo experiments corroborated the synergistic effects of cisplatin and verteporfin (a YAP inhibitor) in combating platinum resistance. Targeting YAP emerges as a promising therapeutic strategy for addressing platinum resistance in OSCC, with circ_0002722 serving as a potential therapy target and valuable diagnostic marker. These findings shed light on the underlying mechanisms of platinum resistance, paving the way for the development of effective treatment approaches.

Identification and functional validation of miR-190b-5p and miR-296-3p as novel therapeutic attenuators of liver fibrosis

Background & AimsLiver fibrosis and its end-stage form known as cirrhosis contributes to millions of deaths annually. The lack of robust anti-fibrotic molecules is in part attributed to absence of any functional screens to identify molecular regulators using patient-derived primary human hepatic myofibroblasts, which are key drivers of fibrosis. MethodsHere, to identify robust regulators of fibrosis, we performed functional microRNA screenings in primary human hepatic myofibroblasts followed by in vivo validation in three independent mouse models of fibrosis (toxin, cholestasis and MASH). ResultsWe identified miR-190b-5p and miR-296-3p as robust anti-fibrotic miRNAs that suppress liver fibrosis. Notably, the expression of miR-190b-5p and miR-296-3p was found significantly reduced in human livers with fibrosis. Mechanistically, we discovered hyaluronan synthase 2 (HAS2) and integrin alpha-6 (ITGA6) as novel targets of miR-190b-5p and miR-296-3p, respectively. Furthermore, we demonstrated that the anti-fibrotic properties of miR-190b-5p and miR-296-3p are, at least in part, dependent on HAS2 and ITGA6. Finally, we showed the anti-fibrotic function of both miRNAs in a human liver bud model, which mimics multiple features of human liver. ConclusionsCollectively, in our study we discovered miR-190b-5p and miR-296-3p as two novel anti-fibrotic miRNAs, and that HAS2 and ITGA6 contribute to miR-190b-5p- and miR-296-3p-mediated inhibition of liver fibrosis. These results provide a foundation for future research to explore the clinical utility of miR-190b-5p and miR-296-3p in liver injuries with fibrosis. Impact and ImplicationsLiver fibrosis and cirrhosis contribute to millions of deaths world-wide and, till date, remain as unmet medical needs. In this study, we discovered two microRNAs, miR-190b-5p and miR-296-3p, which suppress liver fibrosis in preclinical mouse models and a human liver bud model. Our promising results encourage further studies that aim to develop both miRNAs for the treatment of liver fibrosis in patients.

Overexpressing miR-222-3p in cultured <i>Mycobacterium Tuberculosis</i>-infected macrophages does not affect their bacteriostatic activity

Tuberculosis, a disease caused by the bacterium Mycobacterium tuberculosis, is a major public health concern. Innate and adaptive immunity provide robust defense against pathogens. However, M. tuberculosis, which co-evolved with humans, has acquired many mechanisms to evade the immune response and ensure its intracellular existence and long-term survival within the host. Moreover, emerging evidence suggests that this secretive bacterium can alter expression of regulatory noncoding RNAs (including microRNAs), leading to dysregulation of biological processes underlying tuberculosis pathogenesis. For example, miR-222-3p has been shown to regulate the functional reprogramming of macrophages and is involved in the regulation of host innate immunity. Previously, we demonstrated the important role of miR-222-3p as a biological marker of tuberculosis activity. To confirm their biological targets and understand their role in the pathogenesis of tuberculosis, many research groups are working to establish functional relationships between miRNA expression under different conditions and their actual biological action using molecular biology and bioinformatics methods. In the present study, we demonstrated the effect of miR-222-3p overexpression on several functions of human macrophages of monocytic origin activated with M. tuberculosis antigens in in vitro culture. Specifically, we found that miR-222-3p overexpression significantly decreased IL-6 and IFNγ expression and increased IL-1β and cxcl10 expression in cultures of uninfected macrophages. Infected macrophages overexpressing miR-222-3p were characterized by increased NF-κB and IL-6 expression, as were infected macrophages without transfection. Another important finding was that miR-222-3p overexpression caused a small but significant increase in reactive nitrogen species production by infected macrophages, but did not affect their bacteriostatic activity against M. tuberculosis. Elucidating the functions of different microRNAs in regulating different pathogenic pathways in TB may lead to discovering new therapeutic targets. The detailed study of microRNAs that regulate immune-associated pathways will be useful for the design of miRNA mimetic molecules, either as inhibitors or as activators. Immune effects induced by miRNA drugs are currently a major challenge for miRNA therapeutics.

Efflux ABC transporters in drug disposition and their posttranscriptional gene regulation by microRNAs.

ATP-binding cassette (ABC) transporters are transmembrane proteins expressed commonly in metabolic and excretory organs to control xenobiotic or endobiotic disposition and maintain their homeostasis. Changes in ABC transporter expression may directly affect the pharmacokinetics of relevant drugs involving absorption, distribution, metabolism, and excretion (ADME) processes. Indeed, overexpression of efflux ABC transporters in cancer cells or bacteria limits drug exposure and causes therapeutic failure that is known as multidrug resistance (MDR). With the discovery of functional noncoding microRNAs (miRNAs) produced from the genome, many miRNAs have been revealed to govern posttranscriptional gene regulation of ABC transporters, which shall improve our understanding of complex mechanism behind the overexpression of ABC transporters linked to MDR. In this article, we first overview the expression and localization of important ABC transporters in human tissues and their clinical importance regarding ADME as well as MDR. Further, we summarize miRNA-controlled posttranscriptional gene regulation of ABC transporters and effects on ADME and MDR. Additionally, we discuss the development and utilization of novel bioengineered miRNA agents to modulate ABC transporter gene expression and subsequent influence on cellular drug accumulation and chemosensitivity. Findings on posttranscriptional gene regulation of ABC transporters shall not only improve our understanding of mechanisms behind variable ADME but also provide insight into developing new means towards rational and more effective pharmacotherapies.

Small RNA and Freeze Survival: The Cryoprotective Functions of MicroRNA in the Frozen Muscle Tissue of the Grey Tree Frog.

The grey tree frog, Dryophytes versicolor, survives whole-body freezing for weeks during cold winter months. Survival in a state devoid of available food, water, or oxygen forces a reliance on metabolic rate depression (MRD) and the reprioritization of bodily functions. This study utilizes next-generation sequencing (NGS) and bioinformatic analyses to characterize changes in the microRNAome of D. versicolor. When comparing control to frozen groups, five microRNAs (miRNA) were found to be differentially regulated (miR-143-3p, miR-30e-3p, miR-10a-5p, miR-140-3p, and miR-148a-3p), suggesting that they play key roles in freeze survival. The KEGG and GO analyses of these changes predicted a significant negative enrichment of terms associated with cell proliferation and active metabolism while simultaneously predicting the upregulation of cell signalling terms. These results suggest a fast-acting regulatory role for miRNA in contributing to the reorganization of gene expression and the limitation of energy-expensive processes during MRD in the hind leg skeletal muscle of the frog.