Is Transforming Stem Cells to Pancreatic Beta Cells Still the Holy Grail for Type 2 Diabetes?

Diabetes is a progressive disease affecting millions of people worldwide. There are several medications and treatment options to improve the life quality of people with diabetes. One of the strategies for the treatment of diabetes could be the use of human pluripotent stem cells or induced pluripotent stem cells. The recent advances in differentiation of stem cells into insulin-secreting beta-like cells in vitro make the transplantation of the stem cell-derived beta-like cells an attractive approach for treatment of type 1 and type 2 diabetes. While stem cell-derived beta-like cells provide an unlimited cell source for beta cell replacement therapies, these cells can also be used as a platform for drug screening or modeling diseases.

Pediatric Graves' disease: decisions regarding therapy.

PURPOSE OF REVIEW: Graves' disease is the most common cause of hyperthyroidism in the pediatric population. It occurs more often in adolescence and in girls; however, prepubertal children tend to have more severe disease, require longer medical therapy, and have a lower rate of remission as compared with pubertal children. The choice of which of the three therapeutic options to use (medical therapy, radioactive iodine ablation, or surgery) must be individualized. This update will focus on the current diagnostic and treatment modalities available, as well as address the controversy that exists with regards to permanent therapy. RECENT FINDINGS: The diagnosis of Graves' disease is often made clinically. With the development of second-generation and third-generation thyroid-stimulating hormone receptor antibody assays, it can be more reliably confirmed. An improved understanding of the underlying autoimmune process and genetics is underway; however, remission rates in children and adolescents remain low. Because of its ease of administration and long-term follow-up, there is a trend towards permanent therapy with radioactive iodine ablation when remission cannot be achieved with medical therapy. SUMMARY: New genes and susceptibility loci have been identified with the hope of better understanding the refractory nature of Graves' disease. Despite the low rates of remission, permanent therapy with radioactive iodine remains a good option.

Two Cases of Thyroiditis in Adolescents Following COVID-19 Vaccinations.

With the onset of the COVID-19 pandemic and the development of widespread vaccination strategies, there have been case reports in the adult literature suggesting an increase in thyroiditis after COVID-19 vaccination. We herein describe 2 children who presented with thyroiditis after COVID-19 vaccination. Two children who received Pfizer-BioNTech COVID-19 messenger RNA vaccines later developed symptoms of thyroid hyperactivity, had positive thyroid-stimulating immunoglobulin (TSI) levels and received treatment directed toward Graves disease. Our case series is the first to demonstrate Graves disease after COVID-19 vaccination in the pediatric population. Given this possibility, it is important for pediatricians to be watchful for symptoms of thyroiditis post vaccination to prevent treatment delays.

Essential roles of insulin and IGF-1 receptors during embryonic lineage development.

The insulin and insulin-like growth factor-1 (IGF-1) receptors are important for the growth and development of embryonic tissues. To directly define their roles in the maintenance of pluripotency and differentiation of stem cells, we knocked out both receptors in induced pluripotent stem cells (iPSCs). iPSCs lacking both insulin and IGF-1 receptors (double knockout, DKO) exhibited preserved pluripotency potential despite decreased expression of transcription factors Lin28a and Tbx3 compared to control iPSCs. While embryoid body and teratoma assays revealed an intact ability of DKO iPSCs to form all three germ layers, the latter were composed of primitive neuroectodermal tumor-like cells in the DKO group. RNA-seq analyses of control vs DKO iPSCs revealed differential regulation of pluripotency, developmental, E2F1, and apoptosis pathways. Signaling analyses pointed to downregulation of the AKT/mTOR pathway and upregulation of the STAT3 pathway in DKO iPSCs in the basal state and following stimulation with insulin/IGF-1. Directed differentiation toward the three lineages was dysregulated in DKO iPSCs, with significant downregulation of key markers (Cebpα, Fas, Pparγ, and Fsp27) in adipocytes and transcription factors (Ngn3, Isl1, Pax6, and Neurod1) in pancreatic endocrine progenitors. Furthermore, differentiated pancreatic endocrine progenitor cells from DKO iPSCs showed increased apoptosis. We conclude that insulin and insulin-like growth factor-1 receptors are indispensable for normal lineage development and perturbations in the function and signaling of these receptors leads to upregulation of alternative compensatory pathways to maintain pluripotency.

An Unusual Cause of Secondary Amenorrhea in an Adolescent: Expanding the Differential.

Secondary amenorrhea is not uncommon in the adolescent female population. There are multiple etiologies to consider, and a comprehensive evaluation is often pursued. Sometimes, however, despite a thorough workup, the diagnosis remains unclear. Here, we report an unusual cause of secondary amenorrhea in a 15-year-old girl. Our patient presented with secondary amenorrhea after a 4-year history of regular menstrual cycles. Her evaluation was notable for very low FSH and low estradiol but normal LH; pregnancy, adrenal, thyroid, prolactin studies, and brain magnetic resonance imaging scan did not reveal a cause of her amenorrhea. Her transabdominal ultrasound showed an enlarged right ovary, initially suggestive of a hemorrhagic cyst. Inhibin A and B were measured because of the persistently low FSH; these were found to be very elevated, concerning for an inhibin-producing tumor. The patient had surgical removal of her right ovary; pathology revealed a juvenile granulosa-cell tumor. Postoperatively, the patient had normalization of serum inhibin A and B and resumption of normal menstrual cycles. This report illustrates that careful consideration of laboratory findings and other studies is essential for correctly identifying the underlying cause of secondary amenorrhea, particularly when the results are not consistent with common causes of this condition.

Breast Cancer Risk in Postmenopausal Women with Medical History of Thyroid Disorder in the Women's Health Initiative.

Background: The association between thyroid disorders and breast cancer remains controversial, in part, due to small cohort sizes and inconsistent findings. We investigated this association in postmenopausal women to determine whether hyper- or hypothyroidism is associated with the risk of developing breast cancer and to determine whether menopausal hormone therapy (MHT) further modifies the risk. Methods: We conducted a prospective cohort study of multiethnic U.S. postmenopausal women aged 50 to 79 years enrolled in both clinical trial and observational study arms between 1993 and 1998 and followed up through February 28, 2017. Development of invasive breast cancer after enrollment was recorded and a history of hyper- or hypothyroidism before the diagnosis of breast cancer was identified. The effect modification by MHT in both study arms was analyzed. All statistical tests were two sided. Results: Among a total of 134,122 women who were included in our study, 8137 participants developed invasive breast cancer during the follow-up period. There was a significant inverse association of invasive breast cancer among women with a history of hypothyroidism (hazard ratio [HR] 0.91, confidence interval [95% CI] 0.86-0.97) and among women who had taken levothyroxine [HR 0.89, 95% CI 0.82-0.96]. Evaluating effect modification by MHT use, the inverse association between hypothyroidism treated with thyroid replacement medications and breast cancer risk was strongest in non-MHT users [HR 0.80, 95% CI 0.69-0.93]. The results did not significantly differ by race/ethnicity. Although a history of hyperthyroidism was associated with an increased risk of invasive breast cancer [HR 1.11, 95% CI 0.91-1.35], this finding did not reach statistical significance. We did not see significant differences in the breast cancer Surveillance, Epidemiology, and End Results stages, histologic types, morphologic grades, or receptor status (estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2) according to thyroid disorder status. Conclusions: Compared with women with no history of thyroid disorder, hypothyroidism was associated with a lower risk of breast cancer. This was mainly seen among those who received thyroid replacement therapy and had never used MHT. Among the treatment options for hypothyroidism, levothyroxine had the strongest inverse association with breast cancer risk.

Insulin Signaling Regulates the FoxM1/PLK1/CENP-A Pathway to Promote Adaptive Pancreatic ß Cell Proliferation.

Investigation of cell-cycle kinetics in mammalian pancreatic ß cells has mostly focused on transition from the quiescent (G0) to G1 phase. Here, we report that centromere protein A (CENP-A), which is required for chromosome segregation during the M-phase, is necessary for adaptive ß cell proliferation. Receptor-mediated insulin signaling promotes DNA-binding activity of FoxM1 to regulate expression of CENP-A and polo-like kinase-1 (PLK1) by modulating cyclin-dependent kinase-1/2. CENP-A deposition at the centromere is augmented by PLK1 to promote mitosis, while knocking down CENP-A limits ß cell proliferation and survival. CENP-A deficiency in ß cells leads to impaired adaptive proliferation in response to pregnancy, acute and chronic insulin resistance, and aging in mice. Insulin-stimulated CENP-A/PLK1 protein expression is blunted in islets from patients with type 2 diabetes. These data implicate the insulin-FoxM1/PLK1/CENP-A pathway-regulated mitotic cell-cycle progression as an essential component in the ß cell adaptation to delay and/or prevent progression to diabetes.

Definition and characterization of a region of 1p36.3 consistently deleted in neuroblastoma.

Substantial genomic and functional evidence from primary tumors and cell lines indicates that a consistent region of distal chromosome 1p is deleted in a sizable proportion of human neuroblastomas, suggesting that this region contains one or more tumor suppressor genes. To determine systematically and precisely the location and extent of 1p deletion in neuroblastomas, we performed allelic loss studies of 737 primary neuroblastomas and genotype analysis of 46 neuroblastoma cell lines. Together, the results defined a single region within 1p36.3 that was consistently deleted in 25% of tumors and 87% of cell lines. Two neuroblastoma patients had constitutional deletions of distal 1p36 that overlapped the tumor-defined region. The tumor- and constitutionally-derived deletions together defined a smallest region of consistent deletion (SRD) between D1S2795 and D1S253. The 1p36.3 SRD was deleted in all but one of the 184 tumors with 1p deletion. Physical mapping and DNA sequencing determined that the SRD minimally spans an estimated 729 kb. Genomic content and sequence analysis of the SRD identified 15 characterized, nine uncharacterized, and six predicted genes in the region. The RNA expression profiles of 21 of the genes were investigated in a variety of normal tissues. The SHREW1 and KCNAB2 genes both had tissue-restricted expression patterns, including expression in the nervous system. In addition, a novel gene (CHD5) with strong homology to proteins involved in chromatin remodeling was expressed mainly in neural tissues. Together, these results suggest that one or more genes involved in neuroblastoma tumorigenesis or tumor progression are likely contained within this region.

Role of microRNAs in epigenetic silencing of the CHD5 tumor suppressor gene in neuroblastomas.

Neuroblastoma (NB), a tumor of the sympathetic nervous system, is the most common extracranial solid tumor of childhood. We and others have identified distinct patterns of genomic change that underlie diverse clinical behaviors, from spontaneous regression to relentless progression. We first identified CHD5 as a tumor suppressor gene that is frequently deleted in NBs. Mutation of the remaining CHD5 allele is rare in these tumors, yet expression is very low or absent, so expression is likely regulated by epigenetic mechanisms. In order to understand the potential role of miRNA regulation of CHD5 protein expression in NBs, we examined all miRNAs that are predicted to target the 3'-UTR using miRanda, TargetScan and other algorithms. We identified 18 miRNAs that were predicted by 2 or more programs: miR-204, -211, -216b, -17, -19ab, -20ab, -93, -106ab, -130ab, -301ab, -454, -519d, -3666. We then performed transient transfections in two NB cell lines, NLF (MYCN amplified) and SY5Y (MYCN non-amplified), with the reporter plasmid and miRNA mimic, as well as appropriate controls. We found seven miRNAs that significantly downregulated CHD5 expression in NB: miR-211, 17, -93, -20b, -106b, -204, and -3666. Interestingly, MYCN upregulates several of the candidates we identified: miR-17, -93, -106b & -20b. This suggests that miRNAs driven by MYCN and other genes represent a potential epigenetic mechanism to regulate CHD5 expression.

CHD5, a tumor suppressor gene deleted from 1p36.31 in neuroblastomas.

BACKGROUND: Neuroblastomas are characterized by hemizygous 1p deletions, suggesting that a tumor suppressor gene resides in this region. We previously mapped the smallest region of consistent deletion to a 2-Mb region of 1p36.31 that encodes 23 genes. Based on mutation analysis, expression pattern, and putative function, we identified CHD5 as the best tumor suppressor gene candidate. METHODS: We determined the methylation status of the CHD5 gene promoter in NLF and IMR5 (with 1p deletion) and SK-N-SH and SK-N-FI neuroblastoma cell lines using methylation-specific sequencing and measured CHD5 mRNA expression by reverse transcription polymerase chain reaction in cells treated with or without 5-aza-2-deoxycytidine, an inhibitor of DNA methylation. We transfected the cells with CHD5 and antisense (AS) CHD5 DNA to assess the effect of CHD5 overexpression and suppression, respectively, on colony formation in soft agar and growth of xenograft tumors in athymic mice. We also analyzed the association of CDH5 expression with outcomes of 99 neuroblastoma patients. Statistical tests were two-sided. RESULTS: CHD5 expression was very low or absent in neuroblastoma cell lines. The CHD5 promoter was highly methylated in NLF and IMR5 lines, and CHD5 expression increased after treatment with 5-aza-2-deoxycytidine. Clonogenicity and tumor growth were abrogated in NLF and IMR5 cells overexpressing CHD5 compared with antisense CHD5 (clonogenicity: mean no. of colonies per plate, NLF-CHD5, 43 colonies, 95% confidence interval [CI] = 35 to 51 colonies, vs NLF-CHD5-AS, 74 colonies, 95% CI = 62 to 86 colonies, P < .001; IMR5-CHD5, 11 colonies, 95% CI = 2 to 20 colonies, vs IMR5-CHD5-AS, 39 colonies, 95% CI = 17 to 60 colonies, P = .01; tumor growth, n = 10 mice per group: mean tumor size at 5 weeks, NLF-CHD5, 0.36 cm(3), 95% CI = 0.17 to 0.44 cm(3), vs NLF-CHD5-AS, 1.65 cm(3), 95% CI = 0.83 to 2.46 cm(3), P = .002; IMR5-CHD5, 0.28 cm(3), 95% CI = 0.18 to 0.38 cm(3), vs IMR5-CHD5-AS, 1.15 cm(3), 95% CI = 0.43 to 1.87 cm(3); P = .01). High CHD5 expression was strongly associated with favorable event-free and overall survival (P < .001), even after correction for MYCN amplification and 1p deletion (P = .027). CONCLUSIONS: CHD5 is the strongest candidate tumor suppressor gene that is deleted from 1p36.31 in neuroblastomas, and inactivation of the second allele may occur by an epigenetic mechanism.