Previously, we reported a method for the attachment of living cells to surfaces through the hybridization of synthetic DNA strands attached to their plasma membrane. The oligonucleotides were introduced using metabolic carbohydrate engineering, which allowed reactive tailoring of the cell surface glycans for chemoselective bioconjugation. While this method is highly effective for cultured mammalian cells, we report here a significant improvement of this technique that allows the direct modification of cell surfaces with NHS-DNA conjugates. This method is rapid and efficient, allowing virtually any mammalian cell to be patterned on surfaces bearing complementary DNA in under 1 h. We demonstrate this technique using several types of cells that are generally incompatible with integrin-targeting approaches, including red blood cells and primary T-cells. Cardiac myoblasts were also captured. The immobilization procedure itself was found not to activate primary T-cells, in contrast to previously reported antibody- and lectin-based methods. Myoblast cells were patterned with high efficiency and remained undifferentiated after surface attachment. Upon changing to differentiation media, myotubes formed in the center of the patterned areas with an excellent degree of edge alignment. The availability of this new protocol greatly expands the applicability of the DNA-based attachment strategy for the generation of artificial tissues and the incorporation of living cells into device settings.
Childhood obesity is increasing at an alarming rate in the United States. This trend carries serious risk of children developing obesity-related diseases including Type 2 diabetes and cardiovascular disease. Non-nutritive sweeteners (NNS) are used as substitution for table sugar as a way to prevent weight gain. Their consumption is ubiquitous in adults and children; however the long-term health outcomes of chronic NNS consumption in children are unclear. Conflicting observational studies suggest that children consuming NNS are at risk of obesity and development of type 2 diabetes, while others concluded some benefits in weight reduction. Here, we review the physiological mechanisms that can contribute to the negative metabolic effects of NNS. We will focus on how NNS alters the sweet perception leading to increase caloric consumption, how NNs alters the gut microbiota, and how NNS may disrupt glucose homeostasis and initiate a vicious cycle of pancreatic endocrine dysfunction. Studies focused on the pediatric population are limited but necessary to determine whether the potential weight loss benefits outweigh the potential negative metabolic outcomes during this critical development period.
Central giant cell granuloma (CGCG) is a rare disease characterized by sporadic, benign, intraosseous mandibular lesions of unknown etiology. Histologically, these lesions are indistinguishable from brown tumors of hyperparathyroidism and cherubism, and occasionally have been associated with different syndromes raising a question for genetic etiology. The CGCG has varied presentation ranging from nonaggressive and indolent to aggressive, destructive, and recurrent, often posing diagnostic and therapeutic challenges. Herein, we present the first case of a 10-year-old boy with CGCG and 16p13.11 microdeletion syndrome, highlight the diagnostic challenges inherent to this heterogeneous disorder, and discuss the genetics and treatment approaches of these complex lesions.
Background: Juvenile onset of primary osteoporosis is a rare skeletal disorder with a highly heterogenous clinical presentation and complex poorly understood genetic etiology. Low-density lipoprotein receptor-related protein 5 (LRP5), a Wnt-β-catenin pathway receptor involved in bone mineral density (BMD) regulation, has been reported in children with primary osteoporosis mainly due to missense and frame-shift mutations. To our knowledge, there is only one report of in-frame deletions in exon 21 possibly being implicated in pregnancy related osteoporosis (1). We report the first case of a rare heterozygous de novo in-frame deletion in exon 21 of LRP5 gene in a girl with juvenile onset primary osteoporosis. Clinical Case: A 7.5 yo previously healthy European-African-American female born to non-consanguineous family, was noted to have left ankle and bilateral wrists fractures during sport activities occurring over the span of 1 y. On exam, she was of normal stature, had normal sclerae and vision, but was found to have hypermobile joints. Initial blood work revealed an elevated iPTH 72 pg/mL (9-59), normal Ca 9.6 mg/dL (8.9-10.4), and low 25OH-Vitamin D 17 ng/mL (30-100), which normalized with supplementation to 30.4 ng/mL. By 10.5 yo, she had sustained multiple sports related and pathologic fractures of long bones with progressive bone pain and functional ambulatory impairment. Radiographic evaluation showed osteopenia, multiple healed long bone fractures with presumed non-ossifying fibroma in the distal right femoral metaphysis, and subtle height loss of T4-5 vertebrae. CT bone densitometry at 12 yo showed low mean cancellous lumbar vertebral BMD of 190 mg/cm3 (ref. 285 ± 45) and normal cortical BMD of the femoral midshaft of 1977 mg/cm3 (ref. 2000 ± 60). Genetic testing for Osteogenesis Imperfecta returned negative for COL1A1 and COL1A2 mutations. Whole exome sequencing (WES) revealed a rare, de novo heterozygous mutation in exon 21 that involved deletion of nucleotides 4454 to 4465 resulting in an in-frame deletion of amino acid 1485 to 1488. This mutation is predicted to be deleterious by in silico analysis. Conclusion: We present the first case of a young female with progressive pathologic fractures, functional ambulatory impairment, and low BMD in childhood, consistent with juvenile onset primary osteoporosis. WES revealed a rare de novo heterozygous in-frame deletion mutation in LRP5, providing a plausible biological mechanism for her clinical presentation, and further contributing to the increasing genetic heterogeneity of juvenile onset primary osteoporosis and LRP5-related bone disorders. Reference: (1) Cook, F., Mumm, S., Whyte, M., Wenkert, D. Pregnancy-associated osteoporosis with a heterozygous deactivating LDL receptor-related protein 5 (LRP5) mutation and a homozygous methylenetetrahydrofolate reductase (MTHRF) polymorphism. JBMR. 2014;29 (4): 922-8.
Presentation of type 1 diabetes (T1D) appears to differ among patients with different ancestries. In this study, medical record data were taken from type 1 diabetes patients, diagnosed from 2010 to 2017 at a single site, UCSF Benioff Children’s Hospital Oakland (BCHO). Patients were grouped into ancestry classes based on medical records. European (EUR; n = 81), Hispanic (HIS; n = 84), and African (AFR; n = 48) groups were compared for C-peptide levels at diagnosis and for levels of four autoantibodies (aAb); insulin (IAA), protein phosphatase-like IA-2 (IA-2A), glutamic acid decarboxylase (GADA), and zinc transporter (ZnT8A). All aAb measurements were performed at a single reference laboratory in Denver. The proportion of patients with no evidence of any aAb was similar in EUR and AFR groups (5% and 4%, respectively) but higher in HIS (14%). For up to three aAb, the number of aAb was correlated with the number of patients in the EUR (r = 0.96; p = 0.039) and AFR (r = 0.96; p = 0.038) groups but not in the HIS group (r = 0.58; p = 0.24). The pattern of autoantibody positivity differed among groups; most prevalent were IA-2A in EUR (75%), GADA in AFR (75%), and both IA-2A and GADA (both at 68%) in HIS. Differences in aAb patterns did not reach statistical significance but were consistent with published reports. As expected, C-peptide levels were below the normal range in the EUR group, regardless of aAb positivity. In contrast, in the HIS group, mean C-peptide levels were in the normal range for patients with up to three positive aAb; only HIS patients with all four aAb positive had C-peptide levels below the normal range. The AFR group was similar to the EUR group, with below normal C-peptide levels, except that the subset of AFR patients with a single positive aAb had C-peptide in the normal range. Observed differences in C-peptide mean and median values were significant between HIS and EUR groups (mean p = 0.013; median p = 0.046). Differences in biomarkers between HIS and EUR T1D patients may have implications for both differential diagnosis and management of T1D. Disclosure N. Keller: None. K.E. Fuller: None. B.J. Shum: None. J. Noble: Employee; Spouse/Partner; Roche Diagnostic USA.
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