RhoA GEF Mcf2lb regulates rosette integrity during collective cell migration

Multicellular rosettes are transient epithelial structures that serve as important cellular intermediates in the formation of diverse organs. Using the zebrafish posterior lateral line primordium (pLLP) as a model system, we investigated the role of the RhoA GEF Mcf2lb in rosette morphogenesis. The pLLP is a group of ∼150 cells that migrates along the zebrafish trunk and is organized into epithelial rosettes; these are deposited along the trunk and will differentiate into sensory organs called neuromasts (NMs). Using single-cell RNA-sequencing and whole-mount in situ hybridization, we showed that mcf2lb is expressed in the pLLP during migration. Live imaging and subsequent 3D analysis of mcf2lb mutant pLLP cells showed disrupted apical constriction and subsequent rosette organization. This resulted in an excess number of deposited NMs along the trunk of the zebrafish. Cell polarity markers ZO-1 and Par-3 were apically localized, indicating that pLLP cells are properly polarized. In contrast, RhoA activity, as well as signaling components downstream of RhoA, Rock2a and non-muscle Myosin II, were diminished apically. Thus, Mcf2lb-dependent RhoA activation maintains the integrity of epithelial rosettes.

Deletion of the mRNA stability factor ELAVL1 (HuR) in pancreatic cancer cells disrupts the tumor microenvironment integrity

Stromal cells promote extensive fibrosis in pancreatic ductal adenocarcinoma (PDAC), which is associated with poor prognosis and therapeutic resistance. We report here for the first time that loss of the RNA-binding protein human antigen R (HuR, ELAVL1) in PDAC cells leads to reprogramming of the tumor microenvironment. In multiple in vivo models, CRISPR deletion of ELAVL1 in PDAC cells resulted in a decrease of collagen deposition, accompanied by a decrease of stromal markers (i.e. podoplanin, α-smooth muscle actin, desmin). RNA-sequencing data showed that HuR plays a role in cell-cell communication. Accordingly, cytokine arrays identified that HuR regulates the secretion of signaling molecules involved in stromal activation and extracellular matrix organization [i.e. platelet-derived growth factor AA (PDGFAA) and pentraxin 3]. Ribonucleoprotein immunoprecipitation analysis and transcription inhibition studies validated PDGFA mRNA as a novel HuR target. These data suggest that tumor-intrinsic HuR supports extrinsic activation of the stroma to produce collagen and desmoplasia through regulating signaling molecules (e.g. PDGFAA). HuR-deficient PDAC in vivo tumors with an altered tumor microenvironment are more sensitive to the standard of care gemcitabine, as compared to HuR-proficient tumors. Taken together, we identified a novel role of tumor-intrinsic HuR in its ability to modify the surrounding tumor microenvironment and regulate PDGFAA.

Diabetes Remission Status During Seven-year Follow-up of the Longitudinal Assessment of Bariatric Surgery Study

CONTEXT

Few studies have examined the clinical characteristics that predict durable, long-term diabetes remission after bariatric surgery.

OBJECTIVE

To compare diabetes prevalence and remission rates during 7-year follow-up after Roux-en-Y gastric bypass (RYGB) and laparoscopic gastric banding (LAGB).

DESIGN

An observational cohort of adults with severe obesity recruited between 2006 and 2009 who completed annual research assessments for up to 7 years after RYGB or LAGB.

SETTING

Ten US hospitals.

PARTICIPANTS

A total sample of 2256 participants, 827 with known diabetes status at both baseline and at least 1 follow-up visit.

INTERVENTIONS

Roux-en-Y gastric bypass or LAGB.

MAIN OUTCOME MEASURES

Diabetes rates and associations of patient characteristics with remission status.

RESULTS

Diabetes remission occurred in 57% (46% complete, 11% partial) after RYGB and 22.5% (16.9% complete, 5.6% partial) after LAGB. Following both procedures, remission was greater in younger participants and those with shorter diabetes duration, higher C-peptide levels, higher homeostatic model assessment of β-cell function (HOMA %B), and lower insulin usage at baseline, and with greater postsurgical weight loss. After LAGB, reduced HOMA insulin resistance (IR) was associated with a greater likelihood of diabetes remission, whereas increased HOMA-%B predicted remission after RYGB. Controlling for weight lost, diabetes remission remained nearly 4-fold higher compared with LAGB.

CONCLUSIONS

Durable, long-term diabetes remission following bariatric surgery is more likely when performed soon after diagnosis when diabetes medication burden is low and beta-cell function is preserved. A greater weight-independent likelihood of diabetes remission after RYGB than LAGB suggests mechanisms beyond weight loss contribute to improved beta-cell function after RYGB.Trial Registration clinicaltrials.gov Identifier: NCT00465829.

Physical and Mental Health-Related Quality of Life Changes Among Insurer Subgroups Following Bariatric Surgery

OBJECTIVE

This study sought to determine improvements in mental and physical health-related quality of life (HRQOL) following bariatric surgery in Medicaid and commercially insured patients.

METHODS

Using data from the Longitudinal Assessment of Bariatric Surgery, an observational cohort study of adults undergoing bariatric surgery (2006-2009), changes in Short Form 36 mental component summary (MCS) and physical component summary (PCS) scores were examined in 1,529 patients who underwent Roux-en-Y gastric bypass, laparoscopic adjustable band, or sleeve gastrectomy and were followed for 5 years. Piecewise linear mixed-effects models estimated MCS and PCS scores as a function of insurance group (Medicaid, N = 177; commercial, N = 1,352) from 0 to 1 year and from 1 to 5 years after surgery, with interactions between insurance group and surgery type.

RESULTS

Patients with Medicaid had lower PCS and MCS scores at baseline. At 1 year after surgery, patients with Medicaid and commercial insurance experienced similar improvement in PCS scores (commercial-Medicaid difference in PCS change [95% CI]: Roux-en-Y gastric bypass, 1.5 [-0.2, 3.3]; laparoscopic adjustable band, 1.9 [-2.2, 6.0]; sleeve gastrectomy, 6.4 [0.0, 12.8]). One-year MCS score improvement was minimal and similar between insurance groups. In years 1 to 5, PCS and MCS scores were stable in all groups.

CONCLUSIONS

Both insurance groups experienced improvements in physical HRQOL and minimal changes in mental HRQOL.

Taar1 gene variants have a causal role in methamphetamine intake and response and interact with Oprm1

We identified a locus on mouse chromosome 10 that accounts for 60% of the genetic variance in methamphetamine intake in mice selectively bred for high versus low methamphetamine consumption. We nominated the trace amine-associated receptor 1 gene, Taar1, as the strongest candidate and identified regulation of the mu-opioid receptor 1 gene, Oprm1, as another contributor. This study exploited CRISPR-Cas9 to test the causal role of Taar1 in methamphetamine intake and a genetically-associated thermal response to methamphetamine. The methamphetamine-related traits were rescued, converting them to levels found in methamphetamine-avoiding animals. We used a family of recombinant inbred mouse strains for interval mapping and to examine independent and epistatic effects of Taar1 and Oprm1. Both methamphetamine intake and the thermal response mapped to Taar1 and the independent effect of Taar1 was dependent on genotype at Oprm1. Our findings encourage investigation of the contribution of Taar1 and Oprm1 variants to human methamphetamine addiction.