No abstract

The gut microbiota contributes to host health and fitness, and imbalances in its composition are associated with pathology. However, what shapes microbiota composition is not clear, in particular the role of genetic factors. Previous work in Caenorhabditis elegans defined a characteristic worm gut microbiota significantly influenced by host genetics. The current work explores the role of central regulators of host immunity and stress resistance, employing qPCR and CFU counts to measure abundance of core microbiota taxa in mutants raised on synthetic communities of previously-isolated worm gut commensals. This revealed a bloom, specifically of Enterobacter species, in immune-compromised TGFβ/BMP mutants. Imaging of fluorescently labeled Enterobacter showed that TGFβ/BMP-exerted control operated primarily in the anterior gut and depended on multi-tissue contributions. Enterobacter commensals are common in the worm gut, contributing to infection resistance. However, disruption of TGFβ/BMP signaling turned a normally beneficial Enterobacter commensal to pathogenic. These results demonstrate specificity in gene-microbe interactions underlying gut microbial homeostasis and highlight the pathogenic potential of their disruption.

Background: Aberrant Hedgehog signaling due to PATCHED or SMOOTHENED mutations is critical to the development of both hereditary and sporadic human basal cell carcinomas (BCCs). GDC-0449 is a first-in-class, potent, oral systemic inhibitor of Hedgehog signal transduction. A dose escalation Phase I trial for refractory solid tumors was conducted. Because of activity seen in initial patients with BCC, an expansion cohort was added to evaluate activity in locally advanced, multifocal, or metastatic BCC patients. Methods: Patients were enrolled in a first-in-human, 3+3 design Phase I study with modified dose doubling to evaluate safety, tolerability, maximum tolerated dose, pharmacokinetics, and pharmacodynamics. In the dose escalation portion, patients received 150, 270, or 540 mg GDC-0449 administered orally as a single dose on day 1, followed by a 1-week pharmacokinetics break, and then once daily on a continuous 28-day schedule (cycle 1=35 days). The expansion cohort BCC patients received 150 mg GDC-0449 daily without interruption beginning day 1. Surrogate tissues were assessed for expression levels of Hedgehog target gene, GLI1. Results: Eight of 9 BCC patients enrolled have been evaluated. In 4 patients with measurable met disease, 2 confirmed RECIST partial responses, 1 stable disease, and 1 progressive disease have been observed. In 4 patients with clinically evaluable locally advanced or multifocal disease, 2 patients had complete response in subcutaneous masses by physical exam and 2 patients had stable disease in skin lesions. One met BCC patient is too early to assess. Metabolic responses by EORTC positron emission tomography (PET) criteria were achieved in 5 out of 5 patients to date. Durable clinical benefit (range 56+ to 375+ days, median 112+ days) was achieved in 8 out of 9 patients. GLI1 expression in skin biopsies was reduced >2-fold in all patients tested to date. Conclusions: GDC-0449 was evaluated in locally advanced, multifocal, and metastatic BCC patients on a continuous daily oral schedule and without significant toxicities. Antitumor activity was observed in almost all BCC patients enrolled, thereby confirming the importance of inhibiting aberrant Hedgehog signaling in BCC. Table 1.BCC Patient Data for GDC-0449 Phase I StudyPt #Disease State (Site)Dose [mg] (Cohort)GLI1 Reduction (>2-fold)PET ResponseRECIST ResponseComments1met150 (DE)++PR*375+ days on study, improved dyspnea, decreased bone pain2LA (ear)270 (DE)++CR (physical exam184+ days, reduced ear canal drainage, mutant PATCHED3met540 (DE)NDNDPD45 days on study, ear lesion healing4met150 (EC)++PR126+ days, improved dyspnea, reduced fatigue5LA (ear)150 (EC++CR (physical exam)112+ days, decreased ear bleeding6MF150 (EC)++SD113+ days, skin lesions healing7met150 (EC)NDNDSD67+ days, improved dyspnea8MF150 (EC)NDPET negSD60+ days, skin lesions healing9met150 (EC)NDTETE56+ days*PR, partial response; CR, complete response; SD, stable disease; PD, progressive disease.

Automated differential counts produced by the Coulter S-Plus IV (S + 4) and the Technicon H-1 (H-1) were compared with routine and reference manual differentials with the use of samples from the adult emergency room (ER) and the neonatal intensive care unit (NICU), populations in which rapid reporting of laboratory results is considered important. Error rates for routine technologists were 9.3% in the ER and 15.3% in the NICU. Error rates for the two instruments were higher than those for technologists with samples from the ER but could be reduced to 4-5% if instrument flags and additional criteria were used to signal the need for a conventional differential. Instrument error rates were higher yet with NICU samples, and specificity was very low (10% for each device). There were small differences between the instruments in detection of immature neutrophils, but flags from the H-1 were more specific (except for detection of nucleated red blood cells in samples from the ER). If either instrument were used in an adult ER and flags and additional criteria were used to signal the need for conventional differentials, 64-75% fewer manual counts would be performed with no decrease in accuracy and a considerable improvement in turnaround time.