Earticle

Background: South Korea has recently faced record-high temperatures, which have adversely affected dairy production. Holstein cows, the primary dairy breed globally, are particularly sensitive to heat stress. In contrast, Jersey cows have shown greater heat tolerance, as demonstrated by phenotypic studies. Methods: We investigated physiological and molecular responses to heat stress in Holstein and Jersey cows by measuring rectal temperature, milk yield, and average daily gain, confirming Holstein cows’ greater vulnerability. To explore molecular mechanisms, we analyzed circulating microRNA profiles from whole blood samples collected under heat stress and normal conditions using microRNA-sequencing. Differential expression patterns were compared between the two breeds to identify biological pathways associated with heat stress. Results: Four microRNAs (bta-miR-20b, bta-miR-1246, bta-miR-2284x, and bta-miR- 2284y) were significantly differentially expressed in both breeds under heat stress (|FC| ≥ 2, p < 0.05). Notably, bta-miR-20b and bta-miR-1246 were linked to corpus luteum function and progesterone biosynthesis, while bta-miR-2284x and bta-miR- 2284y were associated with immune responses. A comparison of 11 potential heat stress-related microRNAs identified in previous studies of Holstein cows revealed consistent expression trends in Jersey cows, albeit with lower fold changes, suggesting their superior heat resilience. Conclusions: Our study highlights the physiological and microRNA-based differences in heat stress responses between Holstein and Jersey cows. Jersey cows exhibited greater resilience, supported by more stable microRNA expression profiles and improved heat stress indicators, making them a promising breed for dairy production in increasingly hot climates.

BACKGROUND/OBJECTIVES: This study investigates correlations between circulating microRNAs (miRNAs) and obesity-related parameters among young women (aged 20-30 years old) in Korea. SUBJECTS/METHODS: We analyzed TaqMan low density arrays (TLDAs) of circulating miRNAs in 9 lean (body mass index [BMI] < 25 kg/㎡) and 15 obese (BMI > 25 kg/㎡) women. We also performed gene ontology (GO) analyses of the biological functions of predicted miRNA target genes, and clustered the results using the database for annotation, visualization and integrated discovery. RESULTS: The TLDA cards contain 754 human miRNAs; of these, the levels of 8 circulating miRNAs significantly declined (> 2-fold) in obese subjects compared with those in lean subjects, including miR-1227, miR-144-5p, miR-192, miR-320, miR-320b, miR-484, miR-324-3p, and miR-378. Among them, miR-484 and miR-378 displayed the most significant inverse correlations with BMI (miR-484, r = -0.5484, P = 0.0056; miR-378, r = -0.5538, P = 0.0050) and visceral fat content (miR-484, r = -0.6141, P = 0.0014; miR-378, r = -0.6090, P = 0.0017). GO analysis indicated that genes targeted by miR-484 and miR-378 had major roles in carbohydrate and lipid metabolism. CONCLUSION: Our result showed the differentially expressed circulating miRNAs in obese subjects compared to lean subjects. Although the mechanistic study to reveal the causal role of miRNAs remains, these miRNAs may be novel biomarkers for obesity.

Purpose: Alzheimer's disease (AD) is the most common form of dementia characterized by progressive memory loss and deteriorated cognitive functions, and early-onset AD (EOAD) is defined as having an age of onset younger than 65 years. There were several attempts to investigate the differences of peripheral microRNA (miRNA) expressions in AD, however we still do not have complete understanding of miRNAs changes in AD, especially EOAD. Therefor we aimed to investigate the alteration of miRNA profiles in AD including EOAD. Materials and Methods: Using Affymetrix microarray analysis, we compared the miRNA profiles in blood plasma of 8 EOAD patients with 8 late-onset AD (LOAD) patients, 8 minor cognitive impairment (MCI) patients and 4 non-demented controls. Results: Our study showed that 2 miRNAs were found to be significantly upregulated in EOAD group compared to Control group, and 10 miRNAs and 2 miRNAs were upregulated in LOAD and MCI groups, respectively. hsa-miR-6756-5p was significantly upregulated in EOAD, LOAD and MCI groups, and hsa-miR-4487 was statistically increased in only EOAD group. Conclusion: Our findings provide new insight into circulating miRNA dysregulation in EOAD and support the potential diagnostic relevance of hsa-miR-4487 as an EOAD-specific biomarker, while hsa-miR-6756-5p may have diagnostic value for AD.

Background and Purpose Stroke is the second leading cause of death and disability worldwide and its diagnosis, and assessment of prognosis, remains challenging. There is a need for improved diagnostic and prognostic biomarkers. MicroRNAs (miRNAs) play important roles in the post-transcriptional regulation of gene expression and their secretion and remarkable stability in biofluids highlights their potential as sensitive biomarkers in the diagnosis and prognosis of acute stroke. Methods We carried out a systematic review to assess current evidence supporting the potential of miRNAs to act as unique diagnostic and prognostic biomarkers in blood samples collected from patients suffering acute stroke within 24 hours of symptoms onset. Results We identified 22 studies eligible for inclusion with 33 dysregulated miRNAs having diagnostic potential in the acute phase of the disease. We identified miR-16, miR-126, and miR-335 as having the highest sensitivity as diagnostic and prognostic biomarkers in acute ischaemic stroke and present original bioinformatic and pathway enrichment analysis of putative miRNA?target interactions. Conclusions miRNAs represent unique biomarkers which have a promising future in stroke diagnosis and prognosis. However, there is a need for more standardized and consistent methodology for the accurate interpretation and translation of miRNAs as novel specific and sensitive biomarkers into clinical practice.

Purpose: The microRNA-34 (miR-34) family is important in tumor regulation. This study aimed to investigate the association of circulating miR-34 family proteins with clinicopathological features and their prognostic value in triple-negative breast cancer (TNBC) patients. Materials and Methods: In this cohort study, 173 TNBC patients admitted to First People’s Hospital of Shunde from May 1, 2009 to April 30, 2013 were enrolled. Meanwhile, 75 age-matched healthy women volunteers were identified as healthy controls (HCs). We examined the expression of miR-34 family (miR-34a/b/c) proteins in plasma collected from TNBC patients before any treatmentwas performed and from age-matched HCs using qPCR methods. Results: The expressions of miR-34a/34b/34c were significantly lower in TNBC patients than in HC (p<0.001, p=0.027, p<0.001, respectively). miR-34a was correlated with tumor grade (p=0.038), lymph node positive (p=0.027), distant metastasis (p=0.004), and surgery (p=0.023); miR-34b was correlated with lymph node positivity (p=0.027); and miR-34c was correlated with tumor grade (p=0.017) and distant metastasis (p<0.001). Kaplan-Meier curve analysis displayed low expression of miR-34a as associated with worse overall survival (OS) (p=0.011), as well as miR-34c low expression (p=0.002). In addition, univariate and multivariate Cox proportional hazards regression was performed, and low expression of miR-34c (p=0.011) was found to be an independent risk factor for OS, as well as tumor grade (p=0.013), lymph node positive (p=0.050), and distant metastasis (p=0.021). Conclusion: In conclusion, this study demonstrated reduced miR-34a/c expression is highly associated with tumor progression and indicated worse prognosis. Also, miR-34c was an independent risk factor for OS in TNBC patients.

In human medicine, circulating microRNAs have been successfully utilized as early biomarkers for various abnormalities and disease states. Vertebrate miR-122 is a liver-specific microRNA which is expressed almost solely in hepatocytes and plays an important role in the regulation of hepatocyte function. In this study, to evaluate the potential utility of circulating miR-122 as a biomarker for liver injury in olive flounder (Paralichthys olivaceus), fish were orally intubated with two doses of acetaminophen (500 mg/kg or 1.000 mg/kg of body weight), and the expression of miR-122 in serum was quantified using real time-PCR. Histological change in liver, and the enzymatic activity of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) were also analyzed. The results showed that miR-122 was higher in acetaminophen administered groups compared to control group. The histopathological effect of acetaminophen on olive flounder liver was not distinct. The serum level of GPT and GOT was increased within 2 folds compared to control group by acetaminophen administration. However, the serum miR-122 level was increased more than 3 or 4 folds compared to the control group by administration of 1000 mg/kg of acetaminophen. These results suggest the possible use of miR-122 as an indicator of liver injury in olive flounder, even when histopathological effects are not distinctive.