Chieri Kuroki

Bio: Chieri Kuroki is an academic researcher from RMIT University. The author has contributed to research in topics: Malaria & Plasmodium vivax. The author has an hindex of 2, co-authored 2 publications receiving 49 citations.

Circulating MicroRNAs as Biomarkers of Colorectal Cancer

Abstract: Colorectal cancer is a common tumor in Japan, causing almost 50,000 deaths per year. The development of new biomarkers is strongly desired, in order to detect the early stage of colorectal cancer with high sensitivity and specificity, using less invasive and high through-put methods. miRNA is a small non-coding RNA which regulates gene expression by digesting mRNA or suppressing translation. miRNAs are stable and present in blood, urine, stool, and other body fluids. The profiles of miRNAs in body fluid are specific to pathological states. There is accumulating data showing the usefulness of miRNAs as new biomarkers for colorectal cancer. We summarize the current knowledge in the previous literature (10 plasma analyses: sensitivity: 83.3 to 89%, specificity: 41 to 84.7%, AUC: 0.606 to 0.896; 13 serum analyses: sensitivity: 66.7 to 96.4%, specificity: 63.9 to 88.1%, AUC: 0.679 to 0.918; and 8 fecal analyses: sensitivity: 70.9 to 81.8%, specificity: 68.4 to 96.3%, AUC: 0.64 to 0.829). We focus on the standardization of miRNA analysis, namely: 1) preanalytical processes: difference of miRNA levels between plasma and serum, sampling methods, preparation of plasma or serum, and preservation of samples; 2) analytical processes: mRNA extraction methods, amplification, normalizer, and cut-off values. In conclusion, miRNAs are expected to become new biomarkers for colorectal cancer screening.

miRNAs as Biomarkers in Disease: Latest Findings Regarding Their Role in Diagnosis and Prognosis

Abstract: MicroRNAs (miRNAs) represent a class of small, non-coding RNAs with the main roles of regulating mRNA through its degradation and adjusting protein levels. In recent years, extraordinary progress has been made in terms of identifying the origin and exact functions of miRNA, focusing on their potential use in both the research and the clinical field. This review aims at improving the current understanding of these molecules and their applicability in the medical field. A thorough analysis of the literature consulting resources available in online databases such as NCBI, PubMed, Medline, ScienceDirect, and UpToDate was performed. There is promising evidence that in spite of the lack of standardized protocols regarding the use of miRNAs in current clinical practice, they constitute a reliable tool for future use. These molecules meet most of the required criteria for being an ideal biomarker, such as accessibility, high specificity, and sensitivity. Despite present limitations, miRNAs as biomarkers for various conditions remain an impressive research field. As current techniques evolve, we anticipate that miRNAs will become a routine approach in the development of personalized patient profiles, thus permitting more specific therapeutic interventions.

Circulating MicroRNAs as Biomarkers for Sepsis

Abstract: Sepsis represents a major cause of lethality during intensive care unit (ICU) treatment. Pharmacological treatment strategies for sepsis are still limited and mainly based on the early initiation of antibiotic and supportive treatment. In this context, numerous clinical and serum based markers have been evaluated for the diagnosis, the severity, and the etiology of sepsis. However until now, few of these factors could be translated into clinical use. MicroRNAs (miRNAs) do not encode for proteins but regulate gene expression by inhibiting the translation or transcription of their target mRNAs. Recently it was demonstrated that miRNAs are released into the circulation and that the spectrum of circulating miRNAs might be altered during various pathologic conditions, such as inflammation, infection, and sepsis. By using array- and single PCR-based methods, a variety of deregulated miRNAs, including miR-25, miR-133a, miR-146, miR-150, and miR-223, were described in the context of sepsis. Some of the miRNAs correlated with the disease stage, as well as patients’ short and long term prognosis. Here, we summarize the current findings on the role of circulating miRNAs in the diagnosis and staging of sepsis in critically ill patients. We compare data from patients with findings from animal models and, finally, highlight the challenges and drawbacks that currently prevent the use of circulating miRNAs as biomarkers in clinical routine.

Circulating MicroRNAs: Potential and Emerging Biomarkers for Diagnosis of Human Infectious Diseases

Abstract: MicroRNAs (miRNAs) are evolutionary conserved, small non-coding RNA with size ranging from 19-24 nucleotides. They endogenously regulate the gene expression at the post transcriptional level either through translation repression or mRNA degradation. MiRNAs have shown the potential to be used as a biomarker for the diagnosis, prognosis and therapy of infectious diseases. Many miRNAs have shown significantly altered expression during infection. The altered expression of miRNA level in an infected human can be identified by the use of advanced diagnostic tools. In this review, we have highlighted the use of miRNA as an emerging tool for the identification of the human infectious disease. Till date, several miRNAs have been reported as a molecular biomarker in infectious diseases, such as miRNA-150 and miRNA-146b-5p in human immunodeficiency virus (HIV); miRNA-122, miRNA-21 and miRNA-34a in hepatitis; miRNA-361-5p and miRNA-29c in tuberculosis; miRNA-16 and miRNA-451 in malaria and miRNA-181 in Helicobacter pylori infection. The diagnosis of infection with the help of a biomarker is a non-invasive tool that has shown to have a key role in early diagnosis of infection. The discovery of circulating miRNA in the blood of infected patients has the potential to become a powerful non-invasive biomarker in coming future.

MicroRNAs: Biological Regulators in Pathogen-Host Interactions.

Abstract: An inflammatory response is essential for combating invading pathogens. Several effector components, as well as immune cell populations, are involved in mounting an immune response, thereby destroying pathogenic organisms such as bacteria, fungi, viruses, and parasites. In the past decade, microRNAs (miRNAs), a group of noncoding small RNAs, have emerged as functionally significant regulatory molecules with the significant capability of fine-tuning biological processes. The important role of miRNAs in inflammation and immune responses is highlighted by studies in which the regulation of miRNAs in the host was shown to be related to infectious diseases and associated with the eradication or susceptibility of the infection. Here, we review the biological aspects of microRNAs, focusing on their roles as regulators of gene expression during pathogen-host interactions and their implications in the immune response against Leishmania, Trypanosoma, Toxoplasma, and Plasmodium infectious diseases.

Non-coding RNAs in Colorectal Cancer

Abstract: One of the long-standing principles of molecular biology is that DNA acts as a template for transcription of messenger RNAs, which serve as blueprints for protein translation. A rapidly growing number of exceptions to this rule have been reported over the past decades: they include long known classes of RNAs involved in translation such as transfer RNAs and ribosomal RNAs, small nuclear RNAs involved in splicing events, and small nucleolar RNAs mainly involved in the modifi cation of other small RNAs, such as ribosomal RNAs and transfer RNAs. More recently, several classes of short regulatory non-coding RNAs, including piwiassociated RNAs, endogenous short-interfering RNAs and microRNAs have been discovered in mammals, which act as key regulators of gene expression in many different cellular pathways and systems. Additionally, the human genome encodes several thousand long non-protein coding RNAs >200 nucleotides in length, some of which play crucial roles in a variety of biological processes such as epigenetic control of chromatin, promoter-specifi c gene regulation, mRNA stability, X-chromosome inactivation and imprinting. In this chapter, we will introduce several classes of short and long non-coding RNAs, describe their diverse roles in mammalian gene regulation and give examples for known modes of action.