Browsing by Author "Mund, Julie Ann"

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    A Synthetic Lethal shRNA Screen and Genetic Proof of Concept Identifies RAC1 as a Novel Target to Disrupt Plexiform Neurofibroma Formation
    (2019-12) Mund, Julie Ann; Clapp, D. Wade; Goebl, Mark; Harrington, Maureen; Brutkiewicz, Randy
    Neurofibromatosis Type 1 (NF1) is a highly penetrant autosomal dominant genetic disorder where mutations in the tumor suppressor gene NF1 leads to decreased neurofibromin. The most debilitating manifestation is the presence of complex multilineage Schwann cell-derived plexiform neurofibromas (PN). Historically, little clinical success has been achieved targeting PN through surgery or chemotherapies. I performed an shRNA library screen of patient-derived Schwann cell lines to identify novel therapeutic targets to disrupt PN formation and progression. An shRNA library screen of human kinases and Rho-GTPases was performed in NF1-/- and paired NF1 competent immortalized Schwann cell lines. Following sequencing, candidates were identified. We previously developed a novel mouse model of NF1 wherein a neural crest specific Postncre targeted loxp-flanked Nf1 that replicated the PN found in patients. Additional cohorts of mice were generated with biallelic deletion of Rac1 (Nf1f/fRac1f/f Postn-Cre+; DKO ). Mice were aged for 9 months and peripheral nerves were harvested and fixed in formalin. Peripheral nerve size was measured and tumors were identified through blinded analysis of hematoxylin and eosin and Masson’s Trichrome (collagen) stained slides. Rho family members, including RAC1, were identified as candidates through an shRNA library screen. Genetic disruption of Rac1 in the Schwann cell lineage resulted in the prevention of tumor formation in DKO mice, as observed by peripheral nerve size and histological analysis. I observed an average of 14.8 +/- 2.65 tumors per mouse in the Nf1f/f Postnviii Cre+ cohort compared to 0 tumors in the DKO (p<0.0001). Following an shRNA library screen, RAC1 was identified as a candidate to modulate PN formation. Biallelic deletion of Rac1 in vivo prevented PN formation. I demonstrate that a candidate identified in an shRNA library screen can translate to an biological effect in a mouse model of PN.
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    Weight loss achieved using an energy restriction diet with normal or higher dietary protein decreased the number of CD14++CD16+ proinflammatory monocytes and plasma lipids and lipoproteins in middle-aged, overweight, and obese adults
    (Elsevier, 2017-04) Kim, Jung Eun; Lin, Ge; Zhou, Jing; Mund, Julie Ann; Case, Jamie; Campbell, Wayne W.; Department of Pediatrics, IU School of Medicine
    Monocytes are involved in immune responses, and specific monocyte subpopulations (MS) that express intermediate to high levels of CD16 are associated with obesity and cardiovascular events. Consuming high protein (HP) when dieting improves body composition and cardiometabolic health outcomes, but whether HP affects MS during weight loss remains unknown. We assessed the effect of HP on energy restriction (ER)–induced changes in MS in overweight and obese adults. The relations between MS and plasma lipids and lipoproteins were also examined. We hypothesized that, independent of protein intake, ER-induced weight loss would decrease the numbers of MS and that MS and plasma lipids and lipoproteins would be related. Thirty-two adults (age 52 ± 1 years, body mass index 31.3 ± 0.5 kg/m2, means ± S.E.) consumed either a normal protein (n=18) or HP (n=14) (0.8 vs 1.5 g•kg−1•d−1 protein) ER diet (750-kcal/d [3138-kJ/d] deficit) for 16 weeks. The HP diet included 0.7 g•kg−1•d−1 of milk protein isolate. Fasting plasma lipids, lipoproteins, and the numbers of MS were analyzed. Over time, independent of protein intake, CD14++CD16+ cell number decreased, whereas CD14dimCD16++, CD14+CD16+, and CD14+CD16− cell numbers remained unchanged. CD14dimCD16++ cell number was negatively associated with total cholesterol (TC) and triglyceride, while CD14++CD16+ cell number was positively associated with TC, low-density lipoprotein cholesterol (LDL), TC to high-density lipoprotein cholesterol (HDL) ratio, and LDL to HDL ratio. Weight loss achieved while consuming an ER diet with either normal or high protein may improve immunity by partially decreasing proinflammatory monocytes. Associations between MS and plasma lipids and lipoproteins are confirmed in overweight and obese adults.