Transcriptomic profiling analysis of the effect of palmitic acid on 3D spheroids of ß-like cells derived from induced pluripotent stem cells.

Type 2 diabetes (T2D) is posing a serious public health concern with a considerable impact on human life and health expenditures worldwide. The disease develops when insulin plasma level is insufficient for coping insulin resistance, caused by the decline of pancreatic ß-cell function and mass. In ß-cells, the lipotoxicity exerted by saturated free fatty acids in particular palmitate (PA), which is chronically elevated in T2D, plays a major role in ß-cell dysfunction and mass. However, there is a lack of human relevant in vitro model to identify the underlying mechanism through which palmitate induces ß-cell failure. In this frame, we have previously developed a cutting-edge 3D spheroid model of ß-like cells derived from human induced pluripotent stem cells. In the present work, we investigated the signaling pathways modified by palmitate in ß-like cells derived spheroids. When compared to the 2D monolayer cultures, the transcriptome analysis (FDR set at  0.1) revealed that the 3D spheroids upregulated the pancreatic markers (such as GCG, IAPP genes), lipids metabolism and transporters (CD36, HMGSC2 genes), glucose transporter (SLC2A6). Then, the 3D spheroids are exposed to PA 0.5 mM for 72 h. The differential analysis demonstrated that 32 transcription factors and 135 target genes were mainly modulated (FDR set at  0.1) including the upregulation of lipid and carbohydrates metabolism (HMGSC2, LDHA, GLUT3), fibrin metabolism (FGG, FGB), apoptosis (CASP7). The pathway analysis using the 135 selected targets extracted the fibrin related biological process and wound healing in 3D PA treated conditions. An overall pathway gene set enrichment analysis, performed on the overall gene set (with pathway significance cutoff at 0.2), highlighted that PA perturbs the citrate cycle, FOXO signaling and Hippo signaling as observed in human islets studies. Additional RT-PCR confirmed induction of inflammatory (IGFBP1, IGFBP3) and cell growth (CCND1, Ki67) pathways by PA. All these changes were associated with unaffected glucose-stimulated insulin secretion (GSIS), suggesting that they precede the defect of insulin secretion and death induced by PA. Overall, we believe that our data demonstrate the potential of our spheroid 3D islet-like cells to investigate the pancreatic-like response to diabetogenic environment.

Correction: Generation of ß-like cell subtypes from differentiated human induced pluripotent stem cells in 3D spheroids.

Correction for 'Generation of ß-like cell subtypes from differentiated human induced pluripotent stem cells in 3D spheroids' by Lisa Morisseau et al., Mol. Omics, 2023, https://doi.org/10.1039/d3mo00050h.

Generation of ß-like cell subtypes from differentiated human induced pluripotent stem cells in 3D spheroids.

Since the identification of four different pancreatic ß-cell subtypes and bi-hormomal cells playing a role in the diabetes pathogenesis, the search for in vitro models that mimics such cells heterogeneity became a key priority in experimental and clinical diabetology. We investigated the potential of human induced pluripotent stem cells to lead to the development of the different ß-cells subtypes in honeycomb microwell-based 3D spheroids. The glucose-stimulated insulin secretion confirmed the spheroids functionality. Then, we performed a single cell RNA sequencing of the spheroids. Using a knowledge-based analysis with a stringency on the pancreatic markers, we extracted the ß-cells INS+/UCN3+ subtype (11%; ß1-like cells), the INS+/ST8SIA1+/CD9- subtype (3%, ß3-like cells) and INS+/CD9+/ST8SIA1-subtype (1%; ß2-like cells) consistently with literature findings. We did not detect the INS+/ST8SIA1+/CD9+ cells (ß4-like cells). Then, we also identified four bi-hormonal cells subpopulations including δ-like cells (INS+/SST+, 6%), γ-like cells (INS+/PPY+, 3%), α-like-cells (INS+/GCG+, 6%) and ε-like-cells (INS+/GHRL+, 2%). Using data-driven clustering, we extracted four progenitors' subpopulations (with the lower level of INS gene) that included one population highly expressing inhibin genes (INHBA+/INHBB+), one population highly expressing KCNJ3+/TPH1+, one population expressing hepatocyte-like lineage markers (HNF1A+/AFP+), and one population expressing stem-like cell pancreatic progenitor markers (SOX2+/NEUROG3+). Furthermore, among the cycling population we found a large number of REST+ cells and CD9+ cells (CD9+/SPARC+/REST+). Our data confirm that our differentiation leads to large ß-cell heterogeneity, which can be used for investigating ß-cells plasticity under physiological and pathophysiological conditions.

Deep Eutectic Solvents Comprising Organic Acids and Their Application in (Bio)Medicine.

Over the last years, we observed a significant increase in the number of published studies that focus on the synthesis and characterization of deep eutectic solvents (DESs). These materials are of particular interest mainly due to their physical and chemical stability, low vapor pressure, ease of synthesis, and the possibility of tailoring their properties through dilution or change of the ratio of parent substances (PS). DESs, considered as one of the greenest families of solvents, are used in many fields, such as organic synthesis, (bio)catalysis, electrochemistry, and (bio)medicine. DESs applications have already been reported in various review articles. However, these reports mainly described these components' basics and general properties without focusing on the particular, PS-wise, group of DESs. Many DESs investigated for potential (bio)medical applications comprise organic acids. However, due to the different aims of the reported studies, many of these substances have not yet been investigated thoroughly, which makes it challenging for the field to move forward. Herein, we propose distinguishing DESs comprising organic acids (OA-DESs) as a specific group derived from natural deep eutectic solvents (NADESs). This review aims to highlight and compare the applications of OA-DESs as antimicrobial agents and drug delivery enhancers-two essential fields in (bio)medical studies where DESs have already been implemented and proven their potential. From the survey of the literature data, it is evident that OA-DESs represent an excellent type of DESs for specific biomedical applications, owing to their negligible cytotoxicity, fulfilling the rules of green chemistry and being generally effective as drug delivery enhancers and antimicrobial agents. The main focus is on the most intriguing examples and (where possible) application-based comparison of particular groups of OA-DESs. This should highlight the importance of OA-DESs and give valuable clues on the direction the field can take.

Pharmacological inhibitors of ß-cell dysfunction and death as therapeutics for diabetes.

More than 500 million adults suffer from diabetes worldwide, and this number is constantly increasing. Diabetes causes 5 million deaths per year and huge healthcare costs per year. ß-cell death is the major cause of type 1 diabetes. ß-cell secretory dysfunction plays a key role in the development of type 2 diabetes. A loss of ß-cell mass due to apoptotic death has also been proposed as critical for the pathogenesis of type 2 diabetes. Death of ß-cells is caused by multiple factors including pro-inflammatory cytokines, chronic hyperglycemia (glucotoxicity), certain fatty acids at high concentrations (lipotoxicity), reactive oxygen species, endoplasmic reticulum stress, and islet amyloid deposits. Unfortunately, none of the currently available antidiabetic drugs favor the maintenance of endogenous ß-cell functional mass, indicating an unmet medical need. Here, we comprehensively review over the last ten years the investigation and identification of molecules of pharmacological interest for protecting ß-cells against dysfunction and apoptotic death which could pave the way for the development of innovative therapies for diabetes.

Polymer-Based Nanostructures for Pancreatic Beta-Cell Imaging and Non-Invasive Treatment of Diabetes.

Diabetes poses major economic, social, and public health challenges in all countries worldwide. Besides cardiovascular disease and microangiopathy, diabetes is a leading cause of foot ulcers and lower limb amputations. With the continued rise of diabetes prevalence, it is expected that the future burden of diabetes complications, early mortality, and disabilities will increase. The diabetes epidemic is partly caused by the current lack of clinical imaging diagnostic tools, the timely monitoring of insulin secretion and insulin-expressing cell mass (beta (ß)-cells), and the lack of patients' adherence to treatment, because some drugs are not tolerated or invasively administrated. In addition to this, there is a lack of efficient topical treatment capable of stopping the progression of disabilities, in particular for treating foot ulcers. In this context, polymer-based nanostructures garnered significant interest due to their tunable physicochemical characteristics, rich diversity, and biocompatibility. This review article emphasizes the last advances and discusses the prospects in the use of polymeric materials as nanocarriers for ß-cell imaging and non-invasive drug delivery of insulin and antidiabetic drugs in the management of blood glucose and foot ulcers.

Venom Peptides, Polyphenols and Alkaloids: Are They the Next Antidiabetics That Will Preserve ß-Cell Mass and Function in Type 2 Diabetes?

Improvement of insulin secretion by pancreatic ß-cells and preservation of their mass are the current challenges that future antidiabetic drugs should meet for achieving efficient and long-term glycemic control in patients with type 2 diabetes (T2D). The successful development of glucagon-like peptide 1 (GLP-1) analogues, derived from the saliva of a lizard from the Helodermatidae family, has provided the proof of concept that antidiabetic drugs directly targeting pancreatic ß-cells can emerge from venomous animals. The literature reporting on the antidiabetic effects of medicinal plants suggests that they contain some promising active substances such as polyphenols and alkaloids, which could be active as insulin secretagogues and ß-cell protectors. In this review, we discuss the potential of several polyphenols, alkaloids and venom peptides from snake, frogs, scorpions and cone snails. These molecules could contribute to the development of new efficient antidiabetic medicines targeting ß-cells, which would tackle the progression of the disease.

Influence of the Size and Charge of Carbon Quantum Dots on Their Corneal Penetration and Permeation Enhancing Properties.

Reaching the corneal endothelium through the topical administration of therapeutic drugs remains a challenge in ophthalmology. Besides, endothelial cells are not able to regenerate, and diseases at this site can lead to corneal blindness. Targeting the corneal endothelium implies efficient penetration through the three corneal layers, which still remains difficult for small molecules. Carbon quantum dots (CQDs) have demonstrated great potential for ocular nanomedicine. This study focuses on the corneal penetration abilities of differently charged CQDs and their use as permeation enhancers for drugs. Excised whole bovine eyes were used as an ex vivo model to investigate corneal penetration of CQDs derived from glucosamine using ß-alanine, ethylenediamine, or spermidine as a passivation agent. It was found that negatively charged CQDs have limited corneal penetration ability, while positively charged CQDs derived from glucosamine hydrochloride and spermidine (CQD-S) penetrate the entire corneal epithelium all the way down to the endothelium. CQD-S were shown to enhance the penetration of FITC-dextran 150 kDa, suggesting that they could be used as efficient penetration enhancers for therapeutic delivery to the corneal endothelium.

Anti-aggregation effect of carbon quantum dots on diabetogenic and beta-cell cytotoxic amylin and beta amyloid heterocomplexes.

Pancreatic islet amyloid deposition is a pathological hallmark of Type 2 diabetes (T2D), contributing to reduced functional ß-cell mass. Islet amyloids result not only from the aggregation and fibrillation of human islet amyloid polypeptide (hIAPP), but also from beta-amyloid 42 (Aß42), the key amyloidogenic peptide linked to Alzheimer's disease. Importantly, Aß42 and hIAPP aggregates (IAPP:Aß42) can interact with each other and form some harmful heterocomplex fibrils. While it is well-documented that hIAPP aggregation occurs only when islets are exposed to a diabetic environment, including hyperglycemia and/or elevated concentrations of saturated fatty acids (SFAs), it remains unclear if hIAPP and IAPP:Aß42 heteromer fibrillations are directly or indirectly triggered by this environment. In this study, we show the interplay between high glucose concentrations and palmitate as the SFA in the aggregation of hIAPP. In addition, we outline that the interaction of hIAPP and Aß42 leads to the formation of complex protein aggregates, which are toxic to ß-cells. Carbon nanocolloids in the form of positively charged carbon quantum dots (CQD-pos) efficiently prevent single amyloid aggregation and the formation of IAPP:Aß42 heterocomplexes. We provide clear evidence with this study that the diabetogenic environment of islets could directly contribute to the formation of homomeric and heteromeric amyloid aggregates and fibrils in T2D. We also propose carbon nanocolloids as biocompatible nanomaterials for developing innovative therapeutic strategies that prevent the decline of functional ß-cell mass.

Nanoparticles and Nanocolloidal Carbon: Will They Be the Next Antidiabetic Class That Targets Fibrillation and Aggregation of Human Islet Amyloid Polypeptide in Type 2 Diabetes?

Nanotechnology is revolutionizing human medicine. Nanoparticles (NPs) are currently used for treating various cancers, for developing vaccines, and for imaging, and other promises offered by NPs might come true soon. Due to the interplay between NPs and proteins, there is more and more evidence supporting the role of NPs for treating amyloid-based diseases. NPs can induce some conformational changes of the adsorbed protein molecules via various molecular interactions, leading to inhibition of aggregation and fibrillation of several and different amyloid proteins. Though an in depth understanding of such interactions between NPs and amyloid structures is still lacking, the inhibition of protein aggregation by NPs represents a new generation of innovative and effective medicines to combat metabolic diseases such as type 2 diabetes (T2D). Here, we lay out advances made in the field of T2D notably for optimizing protein aggregation inhibition strategies. This Account covers discussions about the current understanding of ß-cells, the insulin producing cells within the pancreas, under diabetic conditions, notably increased glucose and fatty acid levels, and the implication of these conditions on the formation of human islet amyloid polypeptide (hIAPP) amylin oligomers and aggregates. Owing to the great potential of carbon nanostructures to interfere with protein aggregation, an important part of this Account will be devoted to the state of the art of therapeutic options in the form of emerging nanomaterials-based amyloidosis inhibitors. Our group has recently made some substantial progress in this regard by investigating the impact of glucose and fatty acid concentrations on hIAPP aggregation and ß-cell toxicity. Furthermore, the great potential of carbon nanocolloids in reversing hIAPP aggregation under diabetic conditions will be highlighted as the approach has been validated on ß-cell cultures from rats. We hope that this Account will evoke new ideas and concepts in this regard. We give some lead references below on pancreatic ß-cell aspects and carbon quantum dots for managing diabetics and nanomedicine related aspects, a topic of interest in our laboratory.

Heat-based transdermal delivery of a ramipril loaded cream for treating hypertension.

Angiotensin-converting enzyme (ACE) inhibitors play an important role in the development of anti-hypertension approaches, with ramipril being one of the most widely used ACE inhibitor prodrugs orally administered once or twice a day. Due to its low bioavailability, large amounts have to be administered to obtain a therapeutic effect. In this work, we propose a ramipril loaded pharmaceutical formulation in contact with an electrothermal actuator based on a gold nanohole array as an efficient approach to increase the transdermal ramipril flux. Using rats as an in vivo model, the effect on the systolic and diastolic blood pressure is evaluated, showing that under optimized conditions the blood pressure could be regulated. Heat activation resulted in total drug delivery out of a bandage loaded with 1 mg ramipril, revealing a flux of 50.9 ± 2.8 µg cm-2 h-1. Importantly, heat-based transdermal dispensing allowed efficient and rapid delivery of ramipril in spontaneously hypertensive rats, with its active form (ramiprilat) detected in blood as early as 5 minutes after delivery onset, accompanied by significant decrease in blood pressure.

Lessons from neonatal ß-cell epigenomic for diabetes prevention and treatment.

Pancreatic ß-cell expansion and functional maturation during the birth-to-weaning period plays an essential role in the adaptation of plasma insulin levels to metabolic needs. These events are driven by epigenetic programs triggered by growth factors, hormones, and nutrients. These mechanisms operating in the neonatal period can be at least in part reactivated in adult life to increase the functional ß-cell mass and face conditions of increased insulin demand such as obesity or pregnancy. In this review, we will highlight the importance of studying these signaling pathways and epigenetic programs to understand the causes of different forms of diabetes and to permit the design of novel therapeutic strategies to prevent and treat this metabolic disorder affecting hundreds of millions of people worldwide.

Photothermal Activatable Mucoadhesive Fiber Mats for On-Demand Delivery of Insulin via Buccal and Corneal Mucosa.

Electrospun fiber mats loaded with therapeutics have gained considerable attention as a versatile tool in the biomedical field. While these bandages are largely based on fast-dissolving polymers to release the cargo, stimuli-responsive fiber mats have the advantages of providing a timely and spatially controlled drug delivery platform, which can be refilled and reused several times. These benefits make electrospun fiber patches original platforms for painless and convenient on-demand hormone release. Because of the high need of more convenient and non-invasive methods for delivering insulin, a hormone that is currently used to treat hundred million people with diabetes worldwide, we have investigated the tremendous potential of reduced graphene oxide modified poly(acrylic acid) based fiber mats as an original platform for buccal and corneal insulin delivery on-demand. The PAA@rGO hydrogel-like fibers rendered water-insoluble by incorporating ß-cyclodextrin, followed by thermal cross-linking, which showed adequate tensile strength along with high adsorption capacity of insulin at pH 7 and good recyclability. The fiber mats maintained good fibrous morphology and high loading efficiency even after five loading-release cycles. The mucoadhesive nature of the fibers allowed their application for insulin delivery via the eye cornea and the buccal mouth lining, as evidenced in ex vivo studies. Insulin loaded PAA@rGO hydrogel-like fibers showed an insulin flux via buccal lining of pigs of 16.6 ± 2.9 µg cm-2 h-1 and 24.3 ± 3.1 µg cm-2 h-1 for porcine cornea. Testing on healthy adult volunteers confirmed the excellent, mucoadhesive nature of the bandage, with three out of six volunteers feeling completely comfortable (note 8.3) while wearing the patches in the buccal cavity.

Innovative transdermal delivery of insulin using gelatin methacrylate-based microneedle patches in mice and mini-pigs.

Painless and controlled on-demand drug delivery is the ultimate goal for the management of various chronic diseases, including diabetes. To achieve this purpose, microneedle patches are gaining increased attention. While degradable microneedle (MN) arrays are widely employed, the use of non-dissolving MN patches remains a challenge to overcome. In this study, we demonstrate that crosslinking gelatin methacrylate with polyethylene glycol diacrylate (PEGDA) is potent for engineering non-dissolving MN arrays. Incorporation of MoS2 nanosheets as a photothermal component into MN hydrogels results in MNs featuring on-demand release properties. An optimized MoS2-MN array patch formed using a hydrogel solution containing 500 µg mL-1 of MoS2 and photochemically crosslinked for 5 min shows required mechanical behavior under a normal compressive load to penetrate the stratum corneum of mice or pig skin and allows the delivery of macromolecular therapeutics such as insulin upon swelling. Using ex vivo and in vivo models, we show that the MoS2-MN patches can be used for loading and releasing insulin for therapeutic purposes. Indeed, transdermal administration of insulin loaded into MoS2-MN patches reduces blood glucose levels in C57BL/6 mice and mini-pigs comparably to subcutaneously injected insulin. We believe that this on-demand delivery system might alter the current insulin therapies and might be a potential approach for delivery of other proteins.

Carbon quantum dots as a dual platform for the inhibition and light-based destruction of collagen fibers: implications for the treatment of eye floaters.

Common in myopia and aging, vitreous opacities arise from clumped collagen fibers within the vitreous body that cast shadows on the retina, appearing as 'floaters' to the patient. Vitreous opacities degrade contrast sensitivity function and can cause significant impairment in vision-related quality-of-life, representing an unmet and underestimated medical need. One therapeutic approach could be the use of versatile light-responsive nanostructures which (i) interfere with the formation of collagen fibers and/or (ii) destroy aggregates of vitreous collagen upon pulsed-laser irradiation at low fluences. In this work, the potential of positively and negatively charged carbon quantum dots (CQDs) to interfere with the aggregation of type I collagen is investigated. We demonstrate that fibrillation of collagen I is prevented most strongly by positively charged CQDs (CQDs-2) and that pulsed-laser illumination allowed to destroy type I collagen aggregates and vitreous opacities (as obtained from patients after vitrectomy) treated with CQDs-2.

Sortilin-derived peptides promote pancreatic beta-cell survival through CREB signaling pathway.

Deterioration of insulin secretion and pancreatic beta-cell mass by inflammatory attacks is one of the main pathophysiological features of type 2 diabetes (T2D). Therefore, preserving beta-cell mass and stimulating insulin secretion only in response to glucose for avoiding the hypoglycemia risks, are the most state-of-the-art option for the treatment of T2D. In this study we tested two correlated hypothesis that 1/ the endogenous peptide released from sortilin, known as PE, that stimulates insulin secretion only in response to glucose, protects beta-cells against death induced by cytokines, and 2/ Spadin and Mini-Spadin, two synthetic peptides derived from PE, that mimic the effects of PE in insulin secretion, also provide beneficial effect on beta-cells survival. We show that PE and its derivatives by inducing a rise of intracellular calcium concentration by depolarizing the membrane protect beta-cells against death induced by Interleukin-1ß. Using biochemical, confocal imaging and cell biology techniques, we reveal that the protective effects of PE and its derivatives rely on the activation of the CaM-Kinase pathway, and on the phosphorylation and activation of the transcription factor CREB. In addition, Mini-Spadin promotes beta-cell proliferation, suggesting its possible regenerative effect. This study highlights new possible roles of PE in pancreatic beta-cell survival and its derivatives as pharmacological tools against diabetes.

The Map3k12 (Dlk)/JNK3 signaling pathway is required for pancreatic beta-cell proliferation during postnatal development.

Unveiling the key pathways underlying postnatal beta-cell proliferation can be instrumental to decipher the mechanisms of beta-cell mass plasticity to increased physiological demand of insulin during weight gain and pregnancy. Using transcriptome and global Serine Threonine Kinase activity (STK) analyses of islets from newborn (10 days old) and adult rats, we found that highly proliferative neonatal rat islet cells display a substantially elevated activity of the mitogen activated protein 3 kinase 12, also called dual leucine zipper-bearing kinase (Dlk). As a key upstream component of the c-Jun amino terminal kinase (Jnk) pathway, Dlk overexpression was associated with increased Jnk3 activity and was mainly localized in the beta-cell cytoplasm. We provide the evidence that Dlk associates with and activates Jnk3, and that this cascade stimulates the expression of Ccnd1 and Ccnd2, two essential cyclins controlling postnatal beta-cell replication. Silencing of Dlk or of Jnk3 in neonatal islet cells dramatically hampered primary beta-cell replication and the expression of the two cyclins. Moreover, the expression of Dlk, Jnk3, Ccnd1 and Ccnd2 was induced in high replicative islet beta cells from ob/ob mice during weight gain, and from pregnant female rats. In human islets from non-diabetic obese individuals, DLK expression was also cytoplasmic and the rise of the mRNA level was associated with an increase of JNK3, CCND1 and CCND2 mRNA levels, when compared to islets from lean and obese patients with diabetes. In conclusion, we find that activation of Jnk3 signalling by Dlk could be a key mechanism for adapting islet beta-cell mass during postnatal development and weight gain.

The impact of chemical engineering and technological advances on managing diabetes: present and future concepts.

Monitoring blood glucose levels for diabetic patients is critical to achieve tight glycaemic control. As none of the current antidiabetic treatments restore lost functional ß-cell mass in diabetic patients, insulin injections and the use of insulin pumps are most widely used in the management of glycaemia. The use of advanced and intelligent chemical engineering, together with the incorporation of micro- and nanotechnological-based processes have lately revolutionized diabetic management. The start of this concept goes back to 1974 with the description of an electrode that repeatedly measures the level of blood glucose and triggers insulin release from an infusion pump to enter the blood stream from a small reservoir upon need. Next to the insulin pumps, other drug delivery routes, including nasal, transdermal and buccal, are currently investigated. These processes necessitate competences from chemists, engineers-alike and innovative views of pharmacologists and diabetologists. Engineered micro and nanostructures hold a unique potential when it comes to drug delivery applications required for the treatment of diabetic patients. As the technical aspects of chemistry, biology and informatics on medicine are expanding fast, time has come to step back and to evaluate the impact of technology-driven chemistry on diabetics and how the bridges from research laboratories to market products are established. In this review, the large variety of therapeutic approaches proposed in the last five years for diabetic patients are discussed in an applied context. A survey of the state of the art of closed-loop insulin delivery strategies in response to blood glucose level fluctuation is provided together with insights into the emerging key technologies for diagnosis and drug development. Chemical engineering strategies centered on preserving and regenerating functional pancreatic ß-cell mass are evoked in addition as they represent a permanent solution for diabetic patients.

Histone deacetylase 9 promoter hypomethylation associated with adipocyte dysfunction is a statin-related metabolic effect.

BACKGROUND: Adipogenesis, the process whereby preadipocytes differentiate into mature adipocytes, is crucial for maintaining metabolic homeostasis. Cholesterol-lowering statins increase type 2 diabetes (T2D) risk possibly by affecting adipogenesis and insulin resistance but the (epi)genetic mechanisms involved are unknown. Here, we characterised the effects of statin treatment on adipocyte differentiation using in vitro human preadipocyte cell model to identify putative effective genes. RESULTS: Statin treatment during adipocyte differentiation caused a reduction in key genes involved in adipogenesis, such as ADIPOQ, GLUT4 and ABCG1. Using Illumina's Infinium '850K' Methylation EPIC array, we found a significant hypomethylation of cg14566882, located in the promoter of the histone deacetylase 9 (HDAC9) gene, in response to two types of statins (atorvastatin and mevastatin), which correlates with an increased HDAC9 mRNA expression. We confirmed that HDAC9 is a transcriptional repressor of the cholesterol efflux ABCG1 gene expression, which is epigenetically modified in obesity and prediabetic states. Thus, we assessed the putative impact of ABCG1 knockdown in mimicking the effect of statin in adipogenesis. ABCG1 KD reduced the expression of key genes involved in adipocyte differentiation and decreased insulin signalling and glucose uptake. In human blood cells from two cohorts, ABCG1 expression was impaired in response to statins, confirming that ABCG1 is targeted in vivo by these drugs. CONCLUSIONS: We identified an epigenetic link between adipogenesis and adipose tissue insulin resistance in the context of T2D risk associated with statin use, which has important implications as HDAC9 and ABCG1 are considered potential therapeutic targets for obesity and metabolic diseases.

Electrothermal patches driving the transdermal delivery of insulin.

Transdermal patches have become a widely used approach for painless delivery of drugs. One major current limitation of these systems remains the restricted skin permeation of proteins and peptides as exemplified by insulin, necessitating different considerations for their successful transdermal delivery. We present a novel patch design based on the integration of nano-engineered heating elements on polyimide substrates for electrothermal transdermal therapy. The results reveal that tuning of the electrical resistivity of an array of gold nanoholes, patterned on polyimide, facilitates a fast-responding electrothermal skin patch, while post-coating with reduced graphene oxide offers capabilities for drug encapsulation, like insulin. Application of insulin-loaded patches to the skin of mice resulted in blood glucose regulation within minutes. While demonstrated for insulin, the skin patches might be well adapted to other low and high molecular weight therapeutic drugs, enabling on-demand electrothermal transdermal delivery.