Louise Torp Dalgaard

Objectives: Human islets are widely researched to understand pathophysiological mechanisms leading to diabetes. Sex, age, and body mass index (BMI) are key donor traits influencing islet function, which is also regulated by an intricate network of microRNAs. Methods: Here, we profiled 754 microRNAs and 58 191 gene transcripts (19 919 protein‐coding) in up to 131 different human islet donor preparations (without diabetes) and assessed their association with donor traits. Additionally, the effect of the age‐associated key microRNAs on relative telomere length in human islet‐derived cells was evaluated. Results: MicroRNA discovery analyses identified miR‐199a‐5p and miR‐214‐3p to be associated (adjusted p ‐value ≤ 0.05) with all three traits (i.e., sex, age, and BMI); miR‐147b‐3p with sex and age; miR‐378a‐5p with sex and BMI; miR‐542‐3p, miR‐34a‐3p, miR‐34a‐5p, miR‐497‐5p and miR‐99a‐5p with age and BMI. After adjusting for covariates, 612 protein‐coding gene transcripts associated with sex (excluding those from sex‐chromosomes), 902 with age, and 250 with BMI. MicroRNA‐199a‐5p and miR‐214‐3p levels negatively correlated with mRNAs critical in islet function, metabolic regulation, and senescence. In vitro validation studies verified that inhibition of two common microRNAs (miR‐199a‐5p/‐214‐3p) slowed down telomere length shortening in human islet‐derived cells. Conclusions: Our analyses identify human islet microRNAs associated with donor traits and provide evidence that these microRNAs can potentially modulate cellular aging phenotype (reflected by relative telomere length) in human islet‐derived cells.

Multiple system atrophy (MSA) is a rare, fatal neurodegenerative disease, pathologically characterized by glial cytoplasmic inclusions (GCIs) containing α-synuclein (αSyn). The causes leading to aberrant αSyn accumulation in oligodendroglia remain unknown. Recent evidence of increased αSyn mRNA in GCI-bearing oligodendrocytes suggests that oligodendroglia αSyn expression may be a key determinant of GCI formation. To ascertain this, we generated a new transgenic (TG) mouse line overexpressing human (h-) αSyn through the myelin basic protein promoter (MBP-hSNCA mice). Immunofluorescence combined with machine learning-based classification confirmed age-independent oligodendroglial αSyn localization, with no evidence of aggregated and pathological αSyn, as assessed by a FRET-based assay, biochemical fractionation, and the seed amplification assay (SAA). Upon intrastriatal inoculation of hαSyn preformed fibrils (hPFFs), the fraction of oligodendroglial αSyn positive insoluble aggregates increased over time in TG compared to wildtype (WT) mice, reaching significance six to nine months after inoculation. This was accompanied by an increase in brain αSyn seeding potency. As proof of concept, we investigated whether preferential oligodendroglia vulnerability is influenced by intrinsic fibril potency by intrastriatally injecting TG and WT mice with αSyn fibrils amplified from 2 MSA or 1 PD patient's brains. Six months post inoculation, MSA-inoculated brains retained the MSA-characteristic seeding profile and exhibited higher seeding potency compared to PD-inoculated mice. TG mice showed significantly more widespread phosphorylated αSyn (pSyn) pathology than WT, independent of whether they were seeded with MSA- or PD-fibrils. However, oligodendroglial inclusions were significantly more abundant in TG mice injected with MSA-derived αSyn. In conclusion, our results indicate that intracellular αSyn expression facilitates the development of oligodendroglial pathology, supporting the hypothesis that increased αSyn expression may represent a rate-limiting step in GCI formation.

Epicardial adipose tissue (EAT) function may influence the heart, given its metabolic actions and proximity to the heart. We hypothesized that diabetes mellitus (DM) alters miRNA expression across adipose tissue types, and that modifications in EAT may have critical implications for cardiac physiology. To test this, we compared EAT and subcutaneous adipose tissue (SAT) miRNA profiles between patients with and without DM and across tissues within each disease group. Paired biopsies from patients with (n = 18) and without DM (n = 46) undergoing cardiac surgery were analyzed using miRNA profiling and bioinformatics. Among 680 miRNAs screened, 34 were uniquely expressed in EAT, confirming a distinct molecular signature in this fat depot. Notably, miR-155-5p was significantly elevated in EAT from patients with DM, indicating a localized metabolic effect. In SAT, miR-93-3p and miR-223-3p were upregulated in patients with DM and consistently higher than in EAT, regardless of DM status, indicating tissue-specific regulation. miR-324-5p was more expressed in SAT of patients in the NDM group, reflecting combined effects of tissue type and DM. These patterns remained consistent across cardiac disease stratifications. Pathway analysis revealed that miRNAs enriched in EAT target genes involved in cardiomyocyte growth and differentiation. Overall, the findings highlight the unique miRNA profile of epicardial fat and its altered response to DM, supporting its relevance in cardiac physiology.

Aims/hypothesis: Upregulation of miR-146a-5p and miR-29-3p is observed in chronic non-healing wounds in diabetes. Their single or combined inhibition's molecular and cellular effects were assessed in human keratinocytes (HaCaT cells) and in vivo using a mouse model of type 1 diabetes. Methods: As primary outcomes, we screened for proteome changes in HaCaT cells by LC-MS/MS after transfection with miR-146a-5p or miR-29a-3p inhibitors individually or in combination and following stimulation with TNF-α. Moreover, as a secondary outcome, we collected the data and cryopreserved and paraffin-embedded skin biopsies to estimate the tissue response to miRNA inhibition using immunofluorescence and histological analysis. Cryopreserved biopsies were also used for the LC-MS/MS proteome profiling to identify targets and cellular pathways involved in observed tissue changes. Results: We identified a panel of extracellular matrix proteins, mainly laminins, whose levels changed after transfection with miR-146a-5p or miR-29a-3p inhibitors in HaCaT cells, counteracting TNF-α effects. There was a difference in wound closure rate in vivo between the dual inhibition of miR-146a-5p and miR-29a-3p and scramble controls on day 8 ( p p p p p p <0.001). This was consistent with cytoskeletal rearrangements and collagen alterations observed in proteome profiling. Conclusions/interpretation: These findings demonstrate that dual inhibition of miR-146a-5p and miR-29a-3p in vitro synergises in a bidirectional manner, resulting either in intermediate effects or in cancelling each other’s activity for the levels of specific proteins of basal lamina that impair proliferation and cell motility, compared with the individual inhibitors. Topical supplementation of miR-146a-5p and miR-29a-3p inhibitors to diabetic mouse wounds resulted in a reduction in wound size on days 8 and 9, which correspond to the later stages of healing, but did not lead to complete healing by day 10. However, dual inhibition demonstrates favourable effects on high oxidative stress, elevated inflammation and poor angiogenesis. These effects are superior to single miRNA inhibition, suggesting that combined miRNA inhibition could be a promising therapeutic strategy for diabetic wound healing. Nevertheless, further studies in humans are warranted. Graphical

Aim: Ovarian cancer (OC) is the leading cause of gynecological cancer deaths. Current biomarkers of OC are not specific or sensitive enough. Extracellular vesicles (EVs), EV surface proteins and their cargo microRNA (miRNA) show potential as biomarkers. This study aimed to characterize the ability of EVs to identify early OC-biomarkers among blood donors six months before their diagnosis. Methods: Study groups of OC patients, benign tumor patients (B), healthy blood donors (Control), and blood donors with incident OC diagnosis within six months of the last blood draw (Pre-diagnostic; PD) were established. Small EVs were enriched from plasma using ultracentrifugation. EVs were characterized by Dynamic Light Scattering (DLS), EV Array, NanoFlow Cytometry, Nanoparticle Tracking Analysis, and Western blots. RNA from EVs was isolated. A discovery study was performed on OC and B patients using the TaqMan Array Human MicroRNA A card. A validation study of 9 specific miRNAs was performed using RT-qPCR. Results: With DLS, it was identified that the OC patients’ EVs were more heterogeneous in size compared to the other groups. Western blot identified CD63 and TSG101 in the EV enrichments. EV Array assessed 22 known protein biomarkers. TaqMan MicroRNA Array cards indicated a differential miRNA abundance between OC and B; however, technical replication and validation could not validate this pattern. Conclusion: This study has analyzed EVs in OC, B, Control, and PD women. More extensive investigations of EV CD9, CD151, and CD81 in conjunction with other risk factors and well-known biomarkers like CA125 or HE4 should be the main objectives of future research.

The worldwide obesity epidemic has led to a drastic increase in diabetes and cardiovascular disease in younger generations. Further, maintaining metabolic health during aging is frequently a challenge due to poor diets and decreased mobility. In this setting, bioactive nutrients that are naturally occurring antioxidants, such as sulforaphane (SFN), are of high nutritional interest. SFN, a bioactive compound that is present in cruciferous vegetables, is a molecule that protects cells from cytotoxic damage and mitigates oxidative stress, protecting against disease. It exerts its action through the activation of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2). Many studies have been performed in animals and humans to evaluate its effects on cancer, brain health, and neurodegenerative disorders. However, fewer clinical studies have been performed to evaluate its effects on insulin resistance and the development of type 2 diabetes mellitus (T2DM) across the lifespan. Given that, in some parts of the world, particularly in Europe, the population is growing older at a significant rate, it is crucial to promote healthy habits (healthy foods, dietary pattern, precision nutrition, and physical activity) from an early stage in life and across the lifespan to avoid debilitating health conditions occurring during adulthood and aging. Thus, in this narrative review, we discuss the protective effects of SFN supplementation on inflammatory and oxidative stress pathways and relate them to metabolic disease.

Diabetes Type 1 and Type 2 are widely occurring diseases. In spite of a vast amount of biomedical literature about diabetic processes in general, links to certain biological processes are only becoming evident these days. One such area of biology is the sulfation of small molecules, such as steroid hormones or metabolites from the gastrointestinal tract, as well as larger biomolecules, such as proteins and proteoglycans. Thus, modulating the physicochemical propensities of the different sulfate acceptors, resulting in enhanced solubility, expedited circulatory transit, or enhanced macromolecular interaction. This review lists evidence for the involvement of sulfation pathways in the maintenance of functional pancreatic beta-cell mass and the implications for diabetes, grouped into various classes of sulfated biomolecule. Complex heparan sulfates might play a role in the development and maintenance of beta-cells. The sulfolipids sulfatide and sulfo-cholesterol might contribute to beta-cell health. In beta-cells, there are only very few proteins with confirmed sulfation on some tyrosine residues, with the IRS4 molecule being one of them. Sulfated steroid hormones, such as estradiol-sulfate and vitamin-D-sulfate, may facilitate downstream steroid signaling in beta-cells, following de-sulfation. Indoxyl sulfate is a metabolite from the intestine, that causes kidney damage, contributing to diabetic kidney disease. Finally, from a technological perspective, there is heparan sulfate, heparin, and chondroitin sulfate, that all might be involved in next-generation beta-cell transplantation. Sulfation pathways may play a role in pancreatic beta-cells through multiple mechanisms. A more coherent understanding of sulfation pathways in diabetes will facilitate discussion and guide future research.

The presence of non-coding RNAs, such as microRNAs (miRNAs), in mitochondria has been reported by several studies. The biological roles and functions of these mitochondrial miRNAs (“mitomiRs”) have not been sufficiently characterized, but the mitochondrial localization of miRNAs has recently gained significance due to modified mitomiR-populations in certain states of diseases. Here, we describe the isolation and analysis of mitochondrial RNAs from rat liver tissue and HepG2 cells. The principle of the analysis is to prepare mitochondria by differential centrifugation. Cytosolic RNA contamination is eliminated by RNase A treatment followed by percoll gradient-purification and RNA-extraction. Small RNA content is verified by capillary electrophoresis. Mitochondrial miRNAs are detected by Q-PCR following synthesis of cDNA. After Q-PCR based mitomiR-profiling, the Normfinder algorithm is applied to identify suitable reference miRNAs to use as normalizers for mitochondrial input and data analysis. The described procedure depicts a simple way of isolating and quantifying mitomiRs in tissue and cell culture samples.