PDGFRβ-P2A-CreER<Superscript>T2</Superscript> mice: a genetic tool to target pericytes in angiogenesis

Pericytes are essential mural cells distinguished by their association with small caliber blood vessels and the presence of a basement membrane shared with endothelial cells. Pericyte interaction with the endothelium plays an important role in angiogenesis; however, very few tools are currently available that allow for the targeting of pericytes in mouse models, limiting our ability to understand their biology. We have generated a novel mouse line expressing tamoxifen-inducible Cre-recombinase under the control of the platelet-derived growth factor receptor β promoter: PDGFRβ-P2A-CreER ^T2 . We evaluated the expression of the PDGFRβ-P2A-CreER ^T2 line by crossing it with fluorescent reporter lines and analyzed reporter signal in the angiogenic retina and brain at different time points after tamoxifen administration. Reporter lines showed labeling of NG2⁺, desmin⁺, PDGFRβ⁺ perivascular cells in the retina and the brain, indicating successful targeting of pericytes; however, signal from reporter lines was also observed in a small subset of glial cells both in the retina and the brain. We also evaluated recombination in tumors and found efficient recombination in perivascular cells associated with tumor vasculature. As a proof of principle, we used our newly generated driver to delete Notch signaling in perivascular cells and observed a loss of smooth muscle cells in retinal arteries, consistent with previously published studies evaluating Notch3 null mice. We conclude that the PDGFRβ-P2A-CreER ^T2 line is a powerful new tool to target pericytes and will aid the field in gaining a deeper understanding of the role of these cells in physiological and pathological settings.     

Persuading People with Depression to Seek Help: Respect the Boomerang

People with depression are likely to process information with a negative bias when confronted with self-relevant information. Accordingly, we feared exposing depressed people to a public service announcement (PSA) addressing the stigma of depression would possibly boomerang and result in less intention to seek help and in increased self-stigma. College students (N?=?271; M_age ?=?22.51, SD?=?4.71; 63.1% female; 37.3% White, 31.9% Hispanic, 12.9% Asian, 6.8% multiethnic, 3.4% Black, 7.6% other) were randomly assigned to receive a print ad focused on depression or a nonrelevant comparison ad. A paper-and-pencil survey consisting of the Beck Depression Inventory–II, Self-Stigma of Seeking Help scale, help-seeking intentions, and demographics followed. Regression analysis indicated that viewing a depression ad caused people with greater depressive symptoms to experience greater levels of self-stigma than depressed people exposed to a nonrelevant comparison ad. Bootstrap mediation analysis showed that for individuals who viewed a depression PSA, self-stigma mediated the relationship between depressive symptoms and professional help-seeking intentions. While this current study offers no direct evidence in regard to the utility of current and past depression campaigns, results indicate a definite need for caution when developing materials targeting people with depression to seek help.     

Ulnar artery aneurysm causing palmar mass in 5-month-old girl

A 5-month-old previously healthy girl presented to the emergency department with a large palpable nontender mass in the hypothenar soft tissues of her left hand. US revealed a well-demarcated nonvascular soft tissue mass. Subsequent MR imaging showed a rim-enhancing mass with heterogeneous intrinsic signal characteristics. Abscess and necrotic tumor were the primary considerations. Surgery demonstrated a thrombosed aneurysm continuous with the ulnar artery system. The aneurysm was resected and the ulnar artery was ligated at the wrist.     

Both frontal and temporal cortex exhibit phonological and semantic specialization during spoken language processing in 7‐ to 8‐year‐old children

A previous functional magnetic resonance imaging (fMRI) study by Weiss et al. (Weiss et al., Human Brain Mapping, 2018, 39, 4334–4348) examined brain specialization for phonological and semantic processing of spoken words in young children who were 5 to 6 years old and found evidence for specialization in the temporal but not the frontal lobe. According to a prominent neurocognitive model of language development (Skeide & Friederici, Nature Reviews Neuroscience, 2016, 17, 323–332), the frontal lobe matures later than the temporal lobe. Thus, the current study aimed to examine if brain specialization in the frontal lobe can be observed in a slightly older cohort of children aged 7 to 8 years old using the same experimental and analytical approach as in Weiss et al. (Weiss et al., Human Brain Mapping, 2018, 39, 4334–4348). One hundred and ten typically developing children were recruited and were asked to perform a sound judgment task, tapping into phonological processing, and a meaning judgment task, tapping into semantic processing, while in the MRI scanner. Direct task comparisons showed that these children exhibited language specialization in both the temporal and the frontal lobes, with the left posterior dorsal inferior frontal gyrus (IFG) showing greater activation for the sound than the meaning judgment task, and the left anterior ventral IFG and the left posterior middle temporal gyrus (MTG) showing greater activation for the meaning than the sound judgment task. These findings demonstrate that 7‐ to 8‐year‐old children have already begun to develop a language‐related specialization in the frontal lobe, suggesting that early elementary schoolers rely on both specialized linguistic manipulation and representation mechanisms to perform language tasks.