Aims/hypothesis Precise regulation of insulin secretion by the pancreatic beta cell is essential for the maintenance of glucose homeostasis. Insulin secretory activity is initiated by the stepwise breakdown of ambient glucose to increase cellular ATP via glycolysis and mitochondrial respiration. Knockout of Lkb1, the gene encoding liver kinase B1 (LKB1) from the beta cell in mice enhances insulin secretory activity by an undefined mechanism. Here, we sought to determine the molecular basis for how deletion of Lkb1 promotes insulin secretion. Methods To explore the role of LKB1 on individual steps in the insulin secretion pathway, we used mitochondrial functional analyses, electrophysiology and metabolic tracing coupled with by gas chromatography and mass spectrometry. Results Beta cells lacking LKB1 surprisingly display impaired mitochondrial metabolism and lower ATP levels following glucose stimulation, yet compensate for this by upregulating both uptake and synthesis of glutamine, leading to increased production of citrate. Furthermore, under low glucose conditions, Lkb1 −/− beta cells fail to inhibit acetyl-CoA carboxylase 1 (ACC1), the rate-limiting enzyme in lipid synthesis, and consequently accumulate NEFA and display increased membrane excitability. Conclusions/interpretation Taken together, our data show that LKB1 plays a critical role in coupling glucose metabolism to insulin secretion, and factors in addition to ATP act as coupling intermediates between feeding cues and secretion. Our data suggest that beta cells lacking LKB1 could be used as a system to identify additional molecular events that connect metabolism to cellular excitation in the insulin secretion pathway.

Long-term impacts of prenatal alcohol exposure (PAE) may include cognitive, physical, and/or behavioral disabilities, collectively called fetal alcohol spectrum disorders (FASD) (Memo et al., 2013). Accurate measurement of PAE in any population is central to the estimation of current and predicted FASD prevalence, helping ensure that commensurate programs and facilities are in place to promote preconception health, educate individuals on the risks of PAE, and refer to substance abuse counseling if necessary (Popova et al., 2017). Rates of PAE can be ascertained by self-report, which is often under-reported for a variety of reasons (e.g., fear of punitive measure, embarrassment, and/or recall bias) or by biomarker quantification (Lange et al., 2014).

Background: Screening newborns for severe combined immunodeficiency (SCID) aims for early identification and treatment of the affected newborns. Adenosine deaminase (ADA) deficiency, a defect in the purine metabolic pathway, is a major cause of SCID and is characterized by the accumulation of adenosine (Ado) and deoxyadenosine (dAdo) in dried blood spots (DBSs). If left untreated, infants with this disorder are at risk of life-threatening infections. Analysis of T-cell receptor excision circles (TRECs) in DBS samples is the gold-standard screening method. However, TREC analysis is insufficient to determine SCID etiology, and a fraction of ADA-SCID may not be detected.

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