Browsing by Subject "Pituitary"

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    In Vivo Analysis of Human LHX3 Gene Regulation
    (2011-02) Mullen, Rachel D.; Rhodes, Simon J.; Herring, B. Paul; Skalnik, David Gordon; Thurmond, Debbie C.; Walvoord, Emily C.
    LHX3 is a transcription factor important in pituitary and nervous system development. Patients with mutations in coding regions of the gene have combined pituitary hormone deficiency (CPHD) that causes growth, fertility, and metabolic problems. Promoter and intronic elements of LHX3 important for basal gene expression in vitro have been identified, but the key regulatory elements necessary for in vivo expression were unknown. With these studies, I sought to elucidate how LHX3 gene expression is regulated in vivo. Based on sequence conservation between species in non-coding regions, I identified a 7.9 kilobase (kb) region 3' of the human LHX3 gene as a potential regulatory element. In a beta galactosidase transgenic mouse model, this region directed spatial and temporal expression to the developing pituitary gland and spinal cord in a pattern consistent with endogenous LHX3 expression. Using a systematic series of deletions, I found that the conserved region contains multiple nervous system enhancers and a minimal 180 base pair (bp) enhancer that direct expression to both the pituitary and spinal cord in transgenic mice. Within this minimal enhancer, TAAT/ATTA sequences that are characteristic of homeodomain protein binding sites are required to direct expression. I performed DNA binding experiments and chromatin immunoprecipitation assays to reveal that the ISL1 and PITX1 proteins specifically recognize these elements in vitro and in vivo. Based on in vivo mutational analyses, two tandem ISL1 binding sites are required for enhancer activity in the pituitary and spine and a PITX1 binding site is required for spatial patterning of gene expression in the pituitary. Additional experiments demonstrated that these three elements cannot alone direct gene expression, suggesting a combination of factors is required for enhancer activity. This study reveals that the key regulatory elements guiding developmental regulation of the human LHX3 gene lie in this conserved downstream region. Further, this work implicates ISL1 as a new transcriptional regulator of LHX3 and describes a possible mechanism for the regulation of LHX3 by a known upstream factor, PITX1. Identification of important regulatory regions will also enable genetic screening in candidate CPHD patients and will thereby facilitate patient treatment and genetic counseling.
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    Outcomes of Initial Management Strategies in Patients With Autoimmune Lymphocytic Hypophysitis: A Systematic Review and Meta-analysis
    (Oxford University Press, 2022) Donegan, Diane; Saeed, Zeb; Delivanis, Danae A.; Murad, Mohammad Hassan; Honegger, Juergen; Amereller, Felix; Oguz, Seda Hanife; Erickson, Dana; Bancps, Irina; Medicine, School of Medicine
    Context: Lymphocytic hypophysitis (LyHy) is characterized by inflammation of the pituitary and or neuroinfundibulum and is uncommon. Treatment options include observation, high-dose glucocorticoids (HD-GCs) or surgery. Optimal first-line management strategy, however, remains unknown. Objective: This work aimed to assess response to first-line treatment options (observation, HD-GCs, or surgery) of clinically relevant outcomes (symptomatic, hormonal, and radiographic improvement) among patients with LyHy. Methods: A systematic review was conducted in 6 databases through 2020. Meta-analysis was conducted when feasible using a random-effects model. Results: We included 33 studies reporting on 591 patients (423 women, 72%) with LyHy. Improvement/resolution of anterior pituitary dysfunction was highest when HD-GCs was first-line treatment. Surgery was associated with the greatest proportion of patients who had regression on imaging. Subgroup analysis comparing HD-GCs to observation showed the odds of anterior pituitary hormone recovery (OR 3.41; 95% CI, 1.68-6.94) or radiographic regression (OR 3.13; 95% CI, 1.54-6.36) were higher with HD-GCs, but so was the need for additional forms of treatment (OR 4.37; 95% CI, 1.70-11.22). No statistically significant difference was seen in recovery of diabetes insipidus (OR 0.9; 95% CI, 0.26-3.10). Certainty in these estimates was very low. Conclusion: Observation and use of HD-GCs both are successful first-line management strategies in LyHy. Although use of HD-GCs was associated with increased recovery of anterior pituitary hormone deficit, it also was associated with greater likelihood of additional treatment after withdrawal. Optimal dosing and duration of HD-GCs remains unknown.