The rising tide raises all ships.

It is easy to feel as if you are alone in academia, especially if you face challenges that not everyone does, or can, understand. Community is essential in facing these challenges, and we each have a role to play in creating a more equitable research community. Here, I discuss the importance of community, finding your village and being part of the academic support system.

Pharmacological inhibition of protein tyrosine phosphatase 1B protects against atherosclerotic plaque formation in the LDLR-/- mouse model of atherosclerosis.

Cardiovascular disease (CVD) is the most prevalent cause of mortality among patients with type 1 or type 2 diabetes, due to accelerated atherosclerosis. Recent evidence suggests a strong link between atherosclerosis and insulin resistance, due to impaired insulin receptor (IR) signalling. Here, we demonstrate that inhibiting the activity of protein tyrosine phosphatase 1B (PTP1B), the major negative regulator of the IR prevents and reverses atherosclerotic plaque formation in an LDLR-/- mouse model of atherosclerosis. Acute (single dose) or chronic PTP1B inhibitor (trodusquemine) treatment of LDLR-/- mice decreased weight gain and adiposity, improved glucose homeostasis and attenuated atherosclerotic plaque formation. This was accompanied by a reduction in both, circulating total cholesterol and triglycerides, a decrease in aortic monocyte chemoattractant protein-1 (MCP-1) expression levels and hyperphosphorylation of aortic Akt/PKB and AMPKα. Our findings are the first to demonstrate that PTP1B inhibitors could be used in prevention and reversal of atherosclerosis development and reduction in CVD risk.

Detection and Eradication of a Demodex Infestation in Specific Pathogen-free High-barrier Laboratory Mouse Facility Housing Immunocompromised Animals.

Demodex mites are a common ectoparasite in nonlaboratory Mus musculus (mouse) populations. While infrequently reported in laboratory research mice, the prevalence is thought to be as high as 35% of all colonies. Here, we discuss an outbreak of Demodex within an SPF high-barrier vivarium housing laboratory mice first identified through commercial sentinel-free PCR testing. Consequently, in-house PCR-mediated identification of individually infected cages was conducted, and a successful method for eradication of secondary reemergent infection was generated via recurrent testing and empirical 12-wk treatment with 3 mg/kg moxidectin and 13 mg/kg imidacloprid. While we were unable to determine the source of our primary outbreak, the secondary outbreak was traced to nongenetically modified C57B6/J immunocompetent mice, which were capable of harboring subclinical infection below our PCR threshold. Our eventual successful eradication of Demodex confirmed, first, that in-house PCR detection is a cost-effective means of monitoring an outbreak; second, that treatment with 3 mg/kg moxidectin and 13 mg/kg imidacloprid does kill Demodex mites in laboratory mice; and third, that treatment of only PCR-positive mice is an insufficient way to control an outbreak. Taken together, our methodological approach for infestations such as Demodex suggests it is possible to eradicate them but that it requires a thorough, systematic, and aggressive treatment regimen. Moreover, we recommend that all cages derived from infected animals be treated as positive, regardless of PCR positivity, to prevent recurrent and/or persistent infections within an animal colony.

SHP2 as a primordial epigenetic enzyme expunges histone H3 pTyr-54 to amend androgen receptor homeostasis.

Mutations that decrease or increase the activity of the tyrosine phosphatase, SHP2 (encoded by PTPN11), promotes developmental disorders and several malignancies by varying phosphatase activity. We uncovered that SHP2 is a distinct class of an epigenetic enzyme; upon phosphorylation by the kinase ACK1/TNK2, pSHP2 was escorted by androgen receptor (AR) to chromatin, erasing hitherto unidentified pY54-H3 (phosphorylation of histones H3 at Tyr54) epigenetic marks to trigger a transcriptional program of AR. Noonan Syndrome with Multiple Lentigines (NSML) patients, SHP2 knock-in mice, and ACK1 knockout mice presented dramatic increase in pY54-H3, leading to loss of AR transcriptome. In contrast, prostate tumors with high pSHP2 and pACK1 activity exhibited progressive downregulation of pY54-H3 levels and higher AR expression that correlated with disease severity. Overall, pSHP2/pY54-H3 signaling acts as a sentinel of AR homeostasis, explaining not only growth retardation, genital abnormalities and infertility among NSML patients, but also significant AR upregulation in prostate cancer patients.

Deficiency in Protein Tyrosine Phosphatase PTP1B Shortens Lifespan and Leads to Development of Acute Leukemia.

Protein tyrosine phosphatase PTP1B is a critical regulator of signaling pathways controlling metabolic homeostasis, cell proliferation, and immunity. In this study, we report that global or myeloid-specific deficiency of PTP1B in mice decreases lifespan. We demonstrate that myeloid-specific deficiency of PTP1B is sufficient to promote the development of acute myeloid leukemia. LysM-PTP1B-/- mice lacking PTP1B in the innate myeloid cell lineage displayed a dysregulation of bone marrow cells with a rapid decline in population at midlife and a concomitant increase in peripheral blood blast cells. This phenotype manifested further with extramedullary tumors, hepatic macrophage infiltration, and metabolic reprogramming, suggesting increased hepatic lipid metabolism prior to overt tumor development. Mechanistic investigations revealed an increase in anti-inflammatory M2 macrophage responses in liver and spleen, as associated with increased expression of arginase I and the cytokines IL10 and IL4. We also documented STAT3 hypersphosphorylation and signaling along with JAK-dependent upregulation of antiapoptotic proteins Bcl2 and BclXL. Our results establish a tumor suppressor role for PTP1B in the myeloid lineage cells, with evidence that its genetic inactivation in mice is sufficient to drive acute myeloid leukemia.Significance: This study defines a tumor suppressor function for the protein tyrosine phosphatase PTP1B in myeloid lineage cells, with evidence that its genetic inactivation in mice is sufficient to drive acute myeloid leukemia. Cancer Res; 78(1); 75-87. ©2017 AACR.

A key role for PTP1B in dendritic cell maturation, migration, and T cell activation.

Dendritic cells (DC) are the major antigen-presenting cells bridging innate and adaptive immunity, a function they perform by converting quiescent DC to active, mature DC with the capacity to activate naïve T cells. They do this by migrating from the tissues to the T cell area of the secondary lymphoid tissues. Here, we demonstrate that myeloid cell-specific genetic deletion of PTP1B (LysM PTP1B) leads to defects in lipopolysaccharide-driven bone marrow-derived DC (BMDC) activation associated with increased levels of phosphorylated Stat3. We show that myeloid cell-specific PTP1B deletion also causes decreased migratory capacity of epidermal DC, as well as reduced CCR7 expression and chemotaxis to CCL19 by BMDC. PTP1B deficiency in BMDC also impairs their migration in vivo. Further, immature LysM PTP1B BMDC display fewer podosomes, increased levels of phosphorylated Src at tyrosine 527, and loss of Src localization to podosome puncta. In co-culture with T cells, LysM PTP1B BMDC establish fewer and shorter contacts than control BMDC. Finally, LysM PTP1B BMDC fail to present antigen to T cells as efficiently as control BMDC. These data provide first evidence for a key regulatory role for PTP1B in mediating a central DC function of initiating adaptive immune responses in response to innate immune cell activation.