Permanent activation of HMGA2 in lipomas mimics its temporal physiological activation linked to the gain of adipose tissue

The Combination of Vascular Endothelial Growth Factor A (VEGF-A) and Fibroblast Growth Factor 1 (FGF1) Modified mRNA Improves Wound Healing in Diabetic Mice: An Ex Vivo and In Vivo Investigation

BACKGROUND

Diabetic foot ulcers (DFU) pose a significant health risk in diabetic patients, with insufficient revascularization during wound healing being the primary cause. This study aimed to assess microvessel sprouting and wound healing capabilities using vascular endothelial growth factor (VEGF-A) and a modified fibroblast growth factor (FGF1).

METHODS

An ex vivo aortic ring rodent model and an in vivo wound healing model in diabetic mice were employed to evaluate the microvessel sprouting and wound healing capabilities of VEGF-A and a modified FGF1 both as monotherapies and in combination.

RESULTS

The combination of VEGF-A and FGF1 demonstrated increased vascular sprouting in the ex vivo mouse aortic ring model, and topical administration of a combination of VEGF-A and FGF1 mRNAs formulated in lipid nanoparticles (LNPs) in mouse skin wounds promoted faster wound closure and increased neovascularization seven days post-surgical wound creation. RNA-sequencing analysis of skin samples at day three post-wound creation revealed a strong transcriptional response of the wound healing process, with the combined treatment showing significant enrichment of genes linked to skin growth.

CONCLUSION

f-LNPs encapsulating VEGF-A and FGF1 mRNAs present a promising approach to improving the scarring process in DFU.

Induction of microRNA hsa-let-7d-5p, and repression of HMGA2, contribute protection against lipid accumulation in macrophage 'foam' cells

Accumulation of excess cholesterol and cholesteryl ester in macrophage 'foam' cells within the arterial intima characterises early 'fatty streak' atherosclerotic lesions, and is accompanied by epigenetic changes, including altered expression of microRNA sequences which determine of gene and protein expression. This study established that exposure to lipoproteins, including acetylated LDL, induced macrophage expression of microRNA hsa-let-7d-5p, a sequence previously linked with tumour suppression, and repressed expression of one of its target genes, high mobility group AT hook 2 (HMGA2). A let-7d-5p mimic repressed expression of HMGA2 (18%; p < 0.05) while a marked increase (2.9-fold; p < 0.05) in expression of HMGA2 was noted in the presence of let-7d-5p inhibitor. Under these conditions, let-7d-5p mimic significantly (p < 0.05) decreased total (10%), free (8%) and cholesteryl ester (21%) mass, while the inhibitor significantly (p < 0.05) increased total (29%) and free cholesterol (29%) mass, compared with the relevant controls. Let-7d-5p inhibition significantly (p < 0.05) increased endogenous biosynthesis of cholesterol (38%) and cholesteryl ester (39%) pools in macrophage 'foam' cells, without altering the cholesterol efflux pathway, or esterification of exogenous radiolabelled oleate. Let-7d-5p inhibition in sterol-loaded cells increased the level of HMGA2 protein (32%; p < 0.05), while SiRNA knockdown of this protein (29%; p < 0.05) resulted in a (21%, p < 0.05) reduction in free cholesterol mass. Thus, induction of let-7d-5p, and repression of its target HMGA2, in macrophages is a protective response to the challenge of increased cholesterol influx into these cells; dysregulation of this response may contribute to atherosclerosis and other disorders such as cancer.

MicroRNA Expression Profiles in the Subcutaneous Adipose Tissues of Morbidly Obese Chinese Women

INTRODUCTION

Obesity is a main global health issue and an outstanding cause of morbidity and mortality. Exploring miRNA profiling may help further studies on obesity.

METHODS

Three morbidly obese and 5 normal-weight Chinese women were enrolled in the microarray testing group. Abdominal subcutaneous adipose tissue (SAT) samples were excised. Total RNAs including miRNAs were extracted. Affymetrix GeneChip miRNA 4.0 Array was used to compare the expression profiles of miRNAs between the 2 groups. Two algorithms, miRanda and TargetScan, were used to predict target messenger RNAs (mRNAs). Bioinformatics analysis was then done based on the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. The sample sizes were further expanded to 8 morbidly obese and 9 normal-weight subjects, and quantitative real-time PCR (qRT-PCR) was utilized to verify the expression of differential miRNAs and target genes.

RESULTS

As per the microarray assay, 58 miRNAs were differentially expressed in the SAT from the morbidly obese and normal-weight groups (Fold >4, p < 0.01, FDR <0.05); 54 of these were downregulated and 4 were upregulated in morbidly obese subjects. A total of 1,333 target genes were jointly predicted by miRanda and TargetScan. Further bioinformatics analysis showed that the differential miRNAs were involved in 269 significant biological functions and 89 significant signaling pathways. The validation experiment by qRT-PCR showed that the expression levels of miRNA-143-5p, miRNA-143-3p, miRNA-145-5p, and let-7a-5p were downregulated in morbidly obese subjects, consistent with the microarray detection. High-mobility group A2 (HMGA2), a target gene of the downregulated miRNA let-7a-5p, was first found to be upregulated 3.19-fold in the SAT of morbidly obese Chinese women when compared to normal-weight controls.

CONCLUSIONS

MiRNA downregulation is a hallmark of intact SAT in a morbidly obese state. Transcription (DNA-dependent), small-molecule metabolic processes, the MAPK signaling pathway, and cancer-related pathways may play important roles in the occurrence and development of obesity. For the first time, we proved that HMGA2, a target gene of let-7a-5p, is upregulated in the SAT of morbidly obese Chinese women.

Gene expression in regenerating and scarring tails of lizard evidences three main key genes (wnt2b, egfl6, and arhgap28) activated during the regulated process of tail regeneration

We have analyzed the expression of key genes orchestrating tail regeneration in lizard under normal and scarring conditions after cauterization. At 1-day post-cauterization (1 dpc), the injured blastema contains degenerating epithelial and mesenchymal cells, numerous mast cells, and immune cells. At 3 and 7 dpc, a stratified wound epidermis is forming while fibrocytes give rise to a scarring connective tissue. Oncogenes such as wnt2b, egfl6, wnt6, and mycn and the tumor suppressor arhgap28 are much more expressed than other oncogenes (hmga2, rhov, fgf8, fgfr4, tert, shh) and tumor suppressors (apcdd1, p63, rb, fat2, bcl11b) in the normal blastema and at 7 dpc. Blastemas at 3 dpc feature the lowest upregulation of most genes, likely derived from damage after cauterization. Immunomodulator genes nfatc4 and lef1 are more expressed at 7 dpc than in normal blastema and 3 dpc suggesting the induction of immune response favoring scarring. Balanced over-expression of oncogenes, tumor suppressor genes, and immune modulator genes determines regulation of cell proliferation (anti-oncogenic), of movement (anti-metastatic), and immunosuppression in the normal blastema. Significant higher expression of oncogenes wnt2b and egfl6 in normal blastema and higher expression of the tumor suppressor arhgap28 in the 7 dpc blastema indicate that they are among the key/master genes that determine the regulated regeneration of the tail.

12q14 microduplication: a new clinical entity reciprocal to the microdeletion syndrome?

Background

12q14 microdeletion syndrome is characterized by low birth weight and failure to thrive, proportionate short stature and developmental delay. The opposite syndrome (microduplication) has not yet been characterized. Our main objective is the recognition of a new clinical entity - 12q14 microduplication syndrome. - as well as confirming the role of HMGA2 gene in growth regulation.

Case presentation

Array Comparative Genomic Hybridization (CGH), Karyotype, Fluorescence in situ Hybridization, Quantitative-PCR analysis and Whole exome sequencing (WES) were performed in a girl presenting overgrowth and obesity. Array CGH identified a 1.5 Mb 12q14.3 microduplication involving HMGA2, GRIP1, IRAK3, MSRB3 and TMBIM4 genes. Karyotype and FISH showed that duplication was a de novo insertion of 12q14.3 region on chromosome 9p resulting in an interstitial microduplication. Q-PCR confirmed the duplication only in the proband. WES revealed no pathogenic variants.

Conclusions

Phenotypic comparison with patients with 12q14 microdeletion syndrome showed a reciprocal presentation, suggesting a phenotypically recognizable 12q14 microduplication syndrome as well as confirming the role of HMGA2 gene in growth regulation. It is also indicative that other genes, such as IRAK3 and MSRB3 might have of role in weight gain and obesity.

Adipose-Derived Stromal Cells from Lipomas: Isolation, Characterisation and Review of the Literature

OBJECTIVE

The aim of this study was to characterize adipose-derived stromal cells (ADSCs) from patients diagnosed with multiple symmetric lipomatosis (MSL) in order to obtain potentially new insights into the pathophysiology, pathogenesis and treatment of this disease.

METHODS

Cells from the stromal vascular fraction were analysed by the colony-forming efficiency assay and flow cytometry using standard markers. Moreover, the power of adipogenic plasticity was evaluated. Finally, a literature review was performed from 1982 to 2015 using the US National Institutes of Health's PubMed database.

RESULTS

Three European-descent patients diagnosed with either MSL type I or II could be identified for analysis. The resulting mean colony-forming efficiency assay was 14.3 ± 5%. Flow-cytometric analysis of the ADSCs revealed high levels of CD34 (70 ± 9%), CD45 (37 ± 13%) and CD73 (55.8 ± 14%), whereas low levels of CD31 (16.8 ± 14%) and CD105 (5.8 ± 0.7%) were detected. Furthermore, ADSCs showed a strong adipogenic potential, which is in line with the literature review. The stem cell pool in lipoma shows several alterations in biological activities, such as proliferation, apoptosis and stemness.

CONCLUSIONS

ADSCs from lipoma may be interesting in the application of regenerative medicine. We discuss possible molecular treatment options to regulate their activities at the source of the MSL.

Gene fusions in soft tissue tumors: Recurrent and overlapping pathogenetic themes

Gene fusions have been described in approximately one-third of soft tissue tumors (STT); of the 142 different fusions that have been reported, more than half are recurrent in the same histologic subtype. These gene fusions constitute pivotal driver mutations, and detailed studies of their cellular effects have provided important knowledge about pathogenetic mechanisms in STT. Furthermore, most fusions are strongly associated with a particular histotype, serving as ideal molecular diagnostic markers. In recent years, it has also become apparent that some chimeric proteins, directly or indirectly, constitute excellent treatment targets, making the detection of gene fusions in STT ever more important. Indeed, pharmacological treatment of STT displaying fusions that activate protein kinases, such as ALK and ROS1, or growth factors, such as PDGFB, is already in clinical use. However, the vast majority (52/78) of recurrent gene fusions create structurally altered and/or deregulated transcription factors, and a small but growing subset develops through rearranged chromatin regulators. The present review provides an overview of the spectrum of currently recognized gene fusions in STT, and, on the basis of the protein class involved, the mechanisms by which they exert their oncogenic effect are discussed.

High mobility group (HMG) proteins: Modulators of chromatin structure and DNA repair in mammalian cells

It has been almost a decade since the last review appeared comparing and contrasting the influences that the different families of High Mobility Group proteins (HMGA, HMGB and HMGN) have on the various DNA repair pathways in mammalian cells. During that time considerable progress has been made in our understanding of how these non-histone proteins modulate the efficiency of DNA repair by all of the major cellular pathways: nucleotide excision repair, base excision repair, double-stand break repair and mismatch repair. Although there are often similar and over-lapping biological activities shared by all HMG proteins, members of each of the different families appear to have a somewhat 'individualistic' impact on various DNA repair pathways. This review will focus on what is currently known about the roles that different HMG proteins play in DNA repair processes and discuss possible future research areas in this rapidly evolving field.

HMGA2 expression in white adipose tissue linking cellular senescence with diabetes

There is a clear link between overweight, gain of white adipose tissue, and diabetes type 2 (T2D). The molecular mechanism of the gain of adipose tissue is linked with the expression of high mobility group protein AT-hook 2 (HMGA2), and recent studies revealed an association with a SNP near HMGA2. In this study, we investigated the gene expression of HMGA2, p14 (Arf) , CDKN1A, and BAX in human abdominal subcutaneous white adipose tissue from 157 patients. We found a significant higher HMGA2 expression in obese individuals than in non-obese patients. Furthermore, the HMGA2 expression in white adipose tissue in patient with type 2 diabetes was significantly higher than in nondiabetic patients. There is an association between the DNA-binding nonhistone protein HMGA2 and the risk of developing T2D that remains mechanistically unexplained so far. Likewise, p14(Arf), an inducer of cellular senescence, has been associated with the occurrence of T2D. The data of the present study provide evidence that both proteins act within the same network to drive proliferation of adipose tissue stem and precursor cells, senescence, and increased risk of T2D, respectively.