Rare Antagonistic Leptin Variants and Severe, Early-Onset Obesity.

Hormone absence or inactivity is common in congenital disease, but hormone antagonism remains controversial. Here, we characterize two novel homozygous leptin variants that yielded antagonistic proteins in two unrelated children with intense hyperphagia, severe obesity, and high circulating levels of leptin. Both variants bind to the leptin receptor but trigger marginal, if any, signaling. In the presence of nonvariant leptin, the variants act as competitive antagonists. Thus, treatment with recombinant leptin was initiated at high doses, which were gradually lowered. Both patients eventually attained near-normal weight. Antidrug antibodies developed in the patients, although they had no apparent effect on efficacy. No severe adverse events were observed. (Funded by the German Research Foundation and others.).

The weakness of senescent dermal fibroblasts.

Skin is the largest human organ with easily noticeable biophysical manifestations of aging. As human tissues age, there is chronological accumulation of biophysical changes due to internal and environmental factors. Skin aging leads to decreased elasticity and the loss of dermal matrix integrity via degradation. The mechanical properties of the dermal matrix are maintained by fibroblasts, which undergo replicative aging and may reach senescence. While the secretory phenotype of senescent fibroblasts is well studied, little is known about changes in the fibroblasts biophysical phenotype. Therefore, we compare biophysical properties of young versus proliferatively aged primary fibroblasts via fluorescence and traction force microscopy, single-cell atomic force spectroscopy, microfluidics, and microrheology of the cytoskeleton. Results show senescent fibroblasts have decreased cytoskeletal tension and myosin II regulatory light chain phosphorylation, in addition to significant loss of traction force. The alteration of cellular forces is harmful to extracellular matrix homeostasis, while decreased cytoskeletal tension can amplify epigenetic changes involved in senescence. Further exploration and detection of these mechanical phenomena provide possibilities for previously unexplored pharmaceutical targets against aging.

The obesity-linked human lncRNA AATBC stimulates mitochondrial function in adipocytes.

Adipocytes are critical regulators of metabolism and energy balance. While white adipocyte dysfunction is a hallmark of obesity-associated disorders, thermogenic adipocytes are linked to cardiometabolic health. As adipocytes dynamically adapt to environmental cues by functionally switching between white and thermogenic phenotypes, a molecular understanding of this plasticity could help improving metabolism. Here, we show that the lncRNA Apoptosis associated transcript in bladder cancer (AATBC) is a human-specific regulator of adipocyte plasticity. Comparing transcriptional profiles of human adipose tissues and cultured adipocytes we discovered that AATBC was enriched in thermogenic conditions. Using primary and immortalized human adipocytes we found that AATBC enhanced the thermogenic phenotype, which was linked to increased respiration and a more fragmented mitochondrial network. Expression of AATBC in adipose tissue of mice led to lower plasma leptin levels. Interestingly, this association was also present in human subjects, as AATBC in adipose tissue was inversely correlated with plasma leptin levels, BMI, and other measures of metabolic health. In conclusion, AATBC is a novel obesity-linked regulator of adipocyte plasticity and mitochondrial function in humans.

Depletion of the RNA-binding protein PURA triggers changes in posttranscriptional gene regulation and loss of P-bodies.

The RNA-binding protein PURA has been implicated in the rare, monogenetic, neurodevelopmental disorder PURA Syndrome. PURA binds both DNA and RNA and has been associated with various cellular functions. Only little is known about its main cellular roles and the molecular pathways affected upon PURA depletion. Here, we show that PURA is predominantly located in the cytoplasm, where it binds to thousands of mRNAs. Many of these transcripts change abundance in response to PURA depletion. The encoded proteins suggest a role for PURA in immune responses, mitochondrial function, autophagy and processing (P)-body activity. Intriguingly, reduced PURA levels decrease the expression of the integral P-body components LSM14A and DDX6 and strongly affect P-body formation in human cells. Furthermore, PURA knockdown results in stabilization of P-body-enriched transcripts, whereas other mRNAs are not affected. Hence, reduced PURA levels, as reported in patients with PURA Syndrome, influence the formation and composition of this phase-separated RNA processing machinery. Our study proposes PURA Syndrome as a new model to study the tight connection between P-body-associated RNA regulation and neurodevelopmental disorders.

Tumor Treating Fields (TTFields) combined with the drug repurposing approach CUSP9v3 induce metabolic reprogramming and synergistic anti-glioblastoma activity in vitro.

BACKGROUND: Glioblastoma represents a brain tumor with a notoriously poor prognosis. First-line therapy may include adjunctive Tumor Treating Fields (TTFields) which are electric fields that are continuously delivered to the brain through non-invasive arrays. On a different note, CUSP9v3 represents a drug repurposing strategy that includes 9 repurposed drugs plus metronomic temozolomide. Here, we examined whether TTFields enhance the antineoplastic activity of CUSP9v3 against this disease. METHODS: We performed preclinical testing of a multimodal approach of TTFields and CUSP9v3 in different glioblastoma models. RESULTS: TTFields had predominantly synergistic inhibitory effects on the cell viability of glioblastoma cells and non-directed movement was significantly impaired when combined with CUSP9v3. TTFields plus CUSP9v3 significantly enhanced apoptosis, which was associated with a decreased mitochondrial outer membrane potential (MOMP), enhanced cleavage of effector caspase 3 and reduced expression of Bcl-2 and Mcl-1. Moreover, oxidative phosphorylation and expression of respiratory chain complexes I, III and IV was markedly reduced. CONCLUSION: TTFields strongly enhance the CUSP9v3-mediated anti-glioblastoma activity. TTFields are currently widely used for the treatment of glioblastoma patients and CUSP9v3 was shown to have a favorable safety profile in a phase Ib/IIa trial (NCT02770378) which facilitates transition of this multimodal approach to the clinical setting.

Adipose tissue: a neglected organ in the response to severe trauma?

Despite the manifold recent efforts to improve patient outcomes, trauma still is a clinical and socioeconomical issue of major relevance especially in younger people. The systemic immune reaction after severe injury is characterized by a strong pro- and anti-inflammatory response. Besides its functions as energy storage depot and organ-protective cushion, adipose tissue regulates vital processes via its secretion products. However, there is little awareness of the important role of adipose tissue in regulating the posttraumatic inflammatory response. In this review, we delineate the local and systemic role of adipose tissue in trauma and outline different aspects of adipose tissue as an immunologically active modifier of inflammation and as an immune target of injured remote organs after severe trauma.

Insulin-inducible THRSP maintains mitochondrial function and regulates sphingolipid metabolism in human adipocytes.

BACKGROUND: Thyroid hormone responsive protein (THRSP) is a lipogenic nuclear protein that is highly expressed in murine adipose tissue, but its role in humans remains unknown. METHODS: We characterized the insulin regulation of THRSP in vivo in human adipose tissue biopsies and in vitro in Simpson-Golabi-Behmel syndrome (SGBS) adipocytes. To this end, we measured whole-body insulin sensitivity using the euglycemic insulin clamp technique in 36 subjects [age 40 ± 9 years, body mass index (BMI) 27.3 ± 5.0 kg/m2]. Adipose tissue biopsies were obtained at baseline and after 180 and 360 min of euglycemic hyperinsulinemia for measurement of THRSP mRNA concentrations. To identify functions affected by THRSP, we performed a transcriptomic analysis of THRSP-silenced SGBS adipocytes. Mitochondrial function was assessed by measuring mitochondrial respiration as well as oxidation and uptake of radiolabeled oleate and glucose. Lipid composition in THRSP silencing was studied by lipidomic analysis. RESULTS: We found insulin to increase THRSP mRNA expression 5- and 8-fold after 180 and 360 min of in vivo euglycemic hyperinsulinemia. This induction was impaired in insulin-resistant subjects, and THRSP expression was closely correlated with whole-body insulin sensitivity. In vitro, insulin increased both THRSP mRNA and protein concentrations in SGBS adipocytes in a phosphoinositide 3-kinase (PI3K)-dependent manner. A transcriptomic analysis of THRSP-silenced adipocytes showed alterations in mitochondrial functions and pathways of lipid metabolism, which were corroborated by significantly impaired mitochondrial respiration and fatty acid oxidation. A lipidomic analysis revealed decreased hexosylceramide concentrations, supported by the transcript concentrations of enzymes regulating sphingolipid metabolism. CONCLUSIONS: THRSP is regulated by insulin both in vivo in human adipose tissue and in vitro in adipocytes, and its expression is downregulated by insulin resistance. As THRSP silencing decreases mitochondrial respiration and fatty acid oxidation, its downregulation in human adipose tissue could contribute to mitochondrial dysfunction. Furthermore, disturbed sphingolipid metabolism could add to metabolic dysfunction in obese adipose tissue.

20 Years with SGBS cells - a versatile in vitro model of human adipocyte biology.

20 years ago, we described a human cell strain derived from subcutaneous adipose tissue of an infant supposed to have Simpson-Golabi-Behmel Syndrome (SGBS), thus called "SGBS cells". Since then, these cells have emerged as the most commonly used cell model for human adipogenesis and human adipocyte biology. Although these adipocyte derived stem cells have not been genetically manipulated for transformation or immortalization, SGBS cells retain their capacity to proliferate and to differentiate into adipocytes for more than 50 population doublings, providing an almost unlimited source of human adipocyte progenitor cells. Original data obtained with SGBS cells led to more than 200 peer reviewed publications comprising investigations on adipogenesis and browning, insulin sensitivity, inflammatory response, adipokine production, as well as co-culture models and cell-cell communication. In this article, we provide an update on the characterization of SGBS cells, present basic methods for their application and summarize results of a systematic literature search on original data obtained with this cell strain.

miR-146a regulates insulin sensitivity via NPR3.

The pathogenesis of obesity-related metabolic diseases has been linked to the inflammation of white adipose tissue (WAT), but the molecular interconnections are still not fully understood. MiR-146a controls inflammatory processes by suppressing pro-inflammatory signaling pathways. The aim of this study was to characterize the role of miR-146a in obesity and insulin resistance. MiR-146a-/- mice were subjected to a high-fat diet followed by metabolic tests and WAT transcriptomics. Gain- and loss-of-function studies were performed using human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes. Compared to controls, miR-146a-/- mice gained significantly more body weight on a high-fat diet with increased fat mass and adipocyte hypertrophy. This was accompanied by exacerbated liver steatosis, insulin resistance, and glucose intolerance. Likewise, adipocytes transfected with an inhibitor of miR-146a displayed a decrease in insulin-stimulated glucose uptake, while transfecting miR-146a mimics caused the opposite effect. Natriuretic peptide receptor 3 (NPR3) was identified as a direct target gene of miR-146a in adipocytes and CRISPR/Cas9-mediated knockout of NPR3 increased insulin-stimulated glucose uptake and enhanced de novo lipogenesis. In summary, miR-146a regulates systemic and adipocyte insulin sensitivity via downregulation of NPR3.

HAND2 is a novel obesity-linked adipogenic transcription factor regulated by glucocorticoid signalling.

AIMS/HYPOTHESIS: Adipocytes are critical cornerstones of energy metabolism. While obesity-induced adipocyte dysfunction is associated with insulin resistance and systemic metabolic disturbances, adipogenesis, the formation of new adipocytes and healthy adipose tissue expansion are associated with metabolic benefits. Understanding the molecular mechanisms governing adipogenesis is of great clinical potential to efficiently restore metabolic health in obesity. Here we investigate the role of heart and neural crest derivatives-expressed 2 (HAND2) in adipogenesis. METHODS: Human white adipose tissue (WAT) was collected from two cross-sectional studies of 318 and 96 individuals. In vitro, for mechanistic experiments we used primary adipocytes from humans and mice as well as human multipotent adipose-derived stem (hMADS) cells. Gene silencing was performed using siRNA or genetic inactivation in primary adipocytes from loxP and or tamoxifen-inducible Cre-ERT2 mouse models with Cre-encoding mRNA or tamoxifen, respectively. Adipogenesis and adipocyte metabolism were measured by Oil Red O staining, quantitative PCR (qPCR), microarray, glucose uptake assay, western blot and lipolysis assay. A combinatorial RNA sequencing (RNAseq) and ChIP qPCR approach was used to identify target genes regulated by HAND2. In vivo, we created a conditional adipocyte Hand2 deletion mouse model using Cre under control of the Adipoq promoter (Hand2AdipoqCre) and performed a large panel of metabolic tests. RESULTS: We found that HAND2 is an obesity-linked white adipocyte transcription factor regulated by glucocorticoids that was necessary but insufficient for adipocyte differentiation in vitro. In a large cohort of humans, WAT HAND2 expression was correlated to BMI. The HAND2 gene was enriched in white adipocytes compared with brown, induced early in differentiation and responded to dexamethasone (DEX), a typical glucocorticoid receptor (GR, encoded by NR3C1) agonist. Silencing of NR3C1 in hMADS cells or deletion of GR in a transgenic conditional mouse model results in diminished HAND2 expression, establishing that adipocyte HAND2 is regulated by glucocorticoids via GR in vitro and in vivo. Furthermore, we identified gene clusters indirectly regulated by the GR-HAND2 pathway. Interestingly, silencing of HAND2 impaired adipocyte differentiation in hMADS and primary mouse adipocytes. However, a conditional adipocyte Hand2 deletion mouse model using Cre under control of the Adipoq promoter did not mirror these effects on adipose tissue differentiation, indicating that HAND2 was required at stages prior to Adipoq expression. CONCLUSIONS/INTERPRETATION: In summary, our study identifies HAND2 as a novel obesity-linked adipocyte transcription factor, highlighting new mechanisms of GR-dependent adipogenesis in humans and mice. DATA AVAILABILITY: Array data have been submitted to the GEO database at NCBI (GSE148699).

Biomarker profile for prediction of response to SMAC mimetic monotherapy in pediatric precursor B-cell acute lymphoblastic leukemia.

Second mitochondria-derived activator of caspase (SMAC) mimetics (SMs) targeting inhibitor of apoptosis proteins (IAPs) activate cell death pathways, and are currently being evaluated in clinical trials. Their successful therapeutic implementation requires upfront identification of patients who could benefit from a SM-based treatment but biomarkers for SM sensitivity have not yet been described. Here, we analyzed the intrinsic activity of two monovalent (AT406 and LCL161) and two bivalent (Birinapant and BV6) SMs on unselected patient-derived pediatric precursor B-cell acute lymphoblastic leukemia (BCP-ALL) identifying a subset of patient samples to be particularly sensitive to SM-induced cell death. This subset was defined by a characteristic gene expression signature with 127 differentially regulated genes, amongst them TNFRSF1A encoding TNFR1, and a critical role of TNFR1 in SM-induced cell death in sensitive BCP-ALL was confirmed on the functional level. Interestingly, samples with intermediate or low sensitivity to SMs were sensitized to SM-induced cell death by inhibition of caspases using zVAD.fmk or Emricasan, a pan-caspase inhibitor in clinical trials. When we compared our expression data to published data sets, we identified an overlap of four genes to be commonly differentially regulated in SM-sensitive BCP-ALL, that is, TSPAN7, DIPK1C, MTX2 and, again, TNFRSF1A. Functional testing revealed that this set of genes identified samples with high sensitivity to SM treatment. In summary, our data suggest using this gene signature as biomarker predicting response to SM treatment and point to the development of new combinatorial treatments consisting of SMs and pan-caspase inhibitors for a successful clinical implementation of SMs in treatment of BCP-ALL.

Induction of apoptosis in ovarian cancer cells by miR-493-3p directly targeting AKT2, STK38L, HMGA2, ETS1 and E2F5.

Apoptosis is a form of directed programmed cell death with a tightly regulated signalling cascade for the destruction of single cells. MicroRNAs (miRNAs) play an important role as fine tuners in the regulation of apoptotic processes. MiR-493-3p mimic transfection leads to the induction of apoptosis causing the breakdown of mitochondrial membrane potential and the activation of Caspases resulting in the fragmentation of DNA in several ovarian carcinoma cell lines. Ovarian cancer shows with its pronounced heterogeneity a very high death-to-incidence ratio. A target gene analysis for miR-493-3p was performed for the investigation of underlying molecular mechanisms involved in apoptosis signalling pathways. Elevated miR-493-3p levels downregulated the mRNA and protein expression levels of Serine/Threonine Kinase 38 Like (STK38L), High Mobility Group AT-Hook 2 (HMGA2) and AKT Serine/Threonine Kinase 2 (AKT2) by direct binding as demonstrated by luciferase reporter assays. Notably, the protein expression of RAF1 Proto-Oncogene, Serine/Threonine Kinase (RAF1) was almost completely downregulated by miR-493-3p. This interaction, however, was indirect and regulated by STK38L phosphorylation. In addition, RAF1 transcription was diminished as a result of reduced transcription of ETS proto-oncogene 1 (ETS1), another direct target of miR-493-3p. Taken together, our observations have uncovered the apoptosis inducing potential of miR-493-3p through its regulation of multiple target genes participating in the extrinsic and intrinsic apoptosis pathway.

Thermogenic Activation Downregulates High Mitophagy Rate in Human Masked and Mature Beige Adipocytes.

Thermogenic brown and beige adipocytes oxidize metabolic substrates producing heat, mainly by the mitochondrial uncoupling protein UCP1, and can thus counteract obesity. Masked beige adipocytes possess white adipocyte-like morphology, but can be made thermogenic by adrenergic stimuli. We investigated the regulation of mitophagy upon thermogenic activation of human masked and mature beige adipocytes. Human primary abdominal subcutaneous adipose-derived stromal cells (hASCs) and Simpson-Golabi-Behmel syndrome (SGBS) preadipocytes were differentiated to white and beige adipocytes, then their cAMP-induced thermogenic potential was assessed by detecting increased expressions of UCP1, mitochondrial DNA content and respiratory chain complex subunits. cAMP increased the thermogenic potential of white adipocytes similarly to beige ones, indicating the presence of a masked beige population. In unstimulated conditions, a high autophagic flux and mitophagy rates (demonstrated by LC3 punctae and TOM20 co-immunostaining) were observed in white adipocytes, while these were lower in beige adipocytes. Silencing and gene expression experiments showed that the ongoing mitophagy was Parkin-independent. cAMP treatment led to the downregulation of mitophagy through PKA in both types of adipocytes, resulting in more fragmented mitochondria and increased UCP1 levels. Our data indicates that mitophagy is repressed upon encountering a short-term adrenergic stimulus, as a fast regulatory mechanism to provide high mitochondrial content for thermogenesis.

CD90 Is Dispensable for White and Beige/Brown Adipocyte Differentiation.

Brown adipose tissue (BAT) is a thermogenic organ in rodents and humans. In mice, the transplantation of BAT has been successfully used to combat obesity and its comorbidities. While such beneficial properties of BAT are now evident, the developmental and cellular origins of brown, beige, and white adipocytes have remained only poorly understood, especially in humans. We recently discovered that CD90 is highly expressed in stromal cells isolated from human white adipose tissue (WAT) compared to BAT. Here, we studied whether CD90 interferes with brown or white adipogenesis or white adipocyte beiging. We applied flow cytometric sorting of human adipose tissue stromal cells (ASCs), a CRISPR/Cas9 knockout strategy in the human Simpson-Golabi-Behmel syndrome (SGBS) adipocyte model system, as well as a siRNA approach in human approaches supports the hypothesis that CD90 affects brown or white adipogenesis or white adipocyte beiging in humans. Taken together, our findings call the conclusions drawn from previous studies, which claimed a central role of CD90 in adipocyte differentiation, into question.

[The immune system of adipose tissue: obesity-associated inflammation]. / Das Fettgewebe im Fokus des Immunsystems: adipositasassoziierte Inflammation.

Adipose tissue is an important endocrine organ. Via its secretion products, it cross-talks with other organs of the body and communicates the filling state of its triglyceride stores. Obesity is characterized by the excessive accumulation of body fat and leads to the infiltration and accumulation of immune cells in white adipose tissue. In this review article we introduce the various immune cell populations of adipose tissue and discuss their local and systemic influence.

Age- and BMI-Associated Expression of Angiogenic Factors in White Adipose Tissue of Children.

The growth of adipose tissue and its vasculature are tightly associated. Angiogenic factors have been linked to obesity, yet little is known about their expression during early childhood. To identify associations of angiogenic factors with characteristics on individual and tissue level, subcutaneous white adipose tissue samples were taken from 45 children aged 0-9 years undergoing elective surgery. We measured the expression of vascular endothelial growth factor A (VEFGA), fibroblast growth factor 1 and 2 (FGF1, FGF2), angiopoietin 1 and 2 (ANGPT1, ANGPT2), TEK receptor tyrosine kinase (TEK), and von Willebrand factor (VWF). In addition, we determined the mean adipocyte size in histologic tissue sections. We found positive correlations of age with FGF1 and FGF2 and a negative correlation with ANGPT2, with pronounced differences in the first two years of life. FGF1, FGF2, and ANGPT1 correlated positively with adipocyte size. Furthermore, we identified a correlation of ANGPT1 and TEK with body mass index-standard deviation score (BMI-SDS), a measure to define childhood obesity. Except for ANGPT2, all angiogenic factors correlated positively with the endothelial marker VWF. In sum, our findings suggest that differences related to BMI-SDS begin early in childhood, and the analyzed angiogenic factors possess distinct roles in adipose tissue biology.

Increased Ifi202b/IFI16 expression stimulates adipogenesis in mice and humans.

AIMS/HYPOTHESIS: Obesity results from a constant and complex interplay between environmental stimuli and predisposing genes. Recently, we identified the IFN-activated gene Ifi202b as the most likely gene responsible for the obesity quantitative trait locus Nob3 (New Zealand Obese [NZO] obesity 3). The aim of this study was to evaluate the effects of Ifi202b on body weight and adipose tissue biology, and to clarify the functional role of its human orthologue IFI16. METHODS: The impact of Ifi202b and its human orthologue IFI16 on adipogenesis was investigated by modulating their respective expression in murine 3T3-L1 and human Simpson-Golabi-Behmel syndrome (SGBS) pre-adipocytes. Furthermore, transgenic mice overexpressing IFI202b were generated and characterised with respect to metabolic traits. In humans, expression levels of IFI16 in adipose tissue were correlated with several variables of adipocyte function. RESULTS: In mice, IFI202b overexpression caused obesity (Δ body weight at the age of 30 weeks: 10.2 ± 1.9 g vs wild-type mice) marked by hypertrophic fat mass expansion, increased expression of Zfp423 (encoding the transcription factor zinc finger protein [ZFP] 423) and white-selective genes (Tcf21, Tle3), and decreased expression of thermogenic genes (e.g. Cidea, Ucp1). Compared with their wild-type littermates, Ifi202b transgenic mice displayed lower body temperature, hepatosteatosis and systemic insulin resistance. Suppression of IFI202b/IFI16 in pre-adipocytes impaired adipocyte differentiation and triacylglycerol storage. Humans with high levels of IFI16 exhibited larger adipocytes, an enhanced inflammatory state and impaired insulin-stimulated glucose uptake in white adipose tissue. CONCLUSIONS/INTERPRETATION: Our findings reveal novel functions of Ifi202b and IFI16, demonstrating their role as obesity genes. These genes promote white adipogenesis and fat storage, thereby facilitating the development of obesity-associated insulin resistance.

Biologically inactive leptin and early-onset extreme obesity.

Mutations in the gene encoding leptin (LEP) typically lead to an absence of circulating leptin and to extreme obesity. We describe a 2-year-old boy with early-onset extreme obesity due to a novel homozygous transversion (c.298G→T) in LEP, leading to a change from aspartic acid to tyrosine at amino acid position 100 (p.D100Y) and high immunoreactive levels of leptin. Overexpression studies confirmed that the mutant protein is secreted but neither binds to nor activates the leptin receptor. The mutant protein failed to reduce food intake and body weight in leptin-deficient ob/ob mice. Treatment of the patient with recombinant human leptin (metreleptin) rapidly normalized eating behavior and resulted in weight loss.

Early childhood BMI trajectories in monogenic obesity due to leptin, leptin receptor, and melanocortin 4 receptor deficiency.

OBJECTIVE: To evaluate whether early childhood body mass index (BMI) is an appropriate indicator for monogenic obesity. METHODS: A cohort of n = 21 children living in Germany or Austria with monogenic obesity due to congenital leptin deficiency (group LEP, n = 6), leptin receptor deficiency (group LEPR, n = 6) and primarily heterozygous MC4 receptor deficiency (group MC4R, n = 9) was analyzed. A control group (CTRL) was defined that consisted of n = 22 obese adolescents with no mutation in the above mentioned genes. Early childhood (0-5 years) BMI trajectories were compared between the groups at selected time points. RESULTS: The LEP and LEPR group showed a tremendous increase in BMI during the first 2 years of life with all patients displaying a BMI >27 kg/m2 (27.2-38.4 kg/m2) and %BMIP95 (percentage of the 95th percentile BMI for age and sex) >140% (144.8-198.6%) at the age of 2 years and a BMI > 33 kg/m2 (33.3-45.9 kg/m2) and %BMIP95 > 184% (184.1-212.6%) at the age of 5 years. The MC4R and CTRL groups had a later onset of obesity with significantly lower BMI values at both time points (p < 0.01). CONCLUSION: As result of the investigation of early childhood BMI trajectories in this pediatric cohort with monogenic obesity we suggest that BMI values >27.0 kg/m2 or %BMIP95 > 140% at the age of 2 years and BMI values >33.0 kg/m2 or %BMIP95 > 184% at the age of 5 years may be useful cut points to identify children who should undergo genetic screening for monogenic obesity due to functionally relevant mutations in the leptin gene or leptin receptor gene.

Impact of X-ray Exposure on the Proliferation and Differentiation of Human Pre-Adipocytes.

Radiotherapy is a widely used treatment option for cancer patients as well as for patients with musculoskeletal disorders. Adipocytes, the dominant cell type of adipose tissue, are known to constitute an active part of the tumor microenvironment. Moreover, adipocytes support inflammatory processes and cartilage degradation in chronic inflammatory diseases, i.e., rheumatoid and osteoarthritis. Since the production of inflammatory factors is linked to their differentiation stages, we set out to explore the radiation response of pre-adipocytes that may influence their inflammatory potential and differentiation capacity. This is the first study investigating the effects of X-ray irradiation on the proliferation and differentiation capacity of human primary pre-adipocytes, in comparison to Simpson⁻Golabi⁻Behmel Syndrome (SGBS) pre-adipocytes, an often-used in vitro model of human primary pre-adipocytes. Our results demonstrate a dose-dependent reduction of the proliferation capacity for both cell strains, whereas the potential for differentiation was mostly unaffected by irradiation. The expression of markers of adipogenic development, such as transcription factors (PPARγ, C/EBPα and C/EBPß), as well as the release of adipokines (visfatin, adiponectin and leptin) were not significantly changed upon irradiation. However, after irradiation with high X-ray doses, an increased lipid accumulation was observed, which suggests a radiation-induced response of adipocytes related to inflammation. Our results indicate that pre-adipocytes are radio-resistant, and it remains to be elucidated whether this holds true for the overall inflammatory response of adipocytes upon irradiation.