All eukaryotic cells have to maintain cholesterol concentrations within defined margins in order to function normally. Perturbing cholesterol homeostasis can result in a wide range of cellular and systemic defects, including cardiovascular diseases, as well as Niemann-Pick and Tangier diseases. Here, we show that DHR96 is indispensable for mediating the transcriptional response to dietary cholesterol and that it acts as a key regulator of the Niemann-Pick type C gene family, as well as of other genes involved in cholesterol uptake, metabolism, and transport. DHR96 mutants are viable and phenotypically normal on a standard medium but fail to survive on diets that are low in cholesterol. DHR96 mutants have aberrant cholesterol levels, demonstrating a defect in maintaining cholesterol homeostasis. Remarkably, we found that a high-cholesterol diet phenocopied the genomic profile of the DHR96 mutation, indicating that DHR96 resides at the top of a genetic hierarchy controlling cholesterol homeostasis in insects. We propose a model whereby DHR96 is activated when cellular cholesterol concentrations drop below a critical threshold in order to protect cells from severe cholesterol deprivation.

Introduction People with neuropathic bladder (NB) secondary to spinal cord injury (SCI) are at risk for multiple genitourinary complications, the most frequent of which is urinary tract infection (UTI). Despite the high frequency with which UTI occurs, our understanding of the role of urinary microbes in health and disease is limited. In this paper, we present the first prospective case study integrating symptom reporting, urinalysis, urine cultivation, and 16S ribosomal ribonucleic acid (rRNA) sequencing of the urine microbiome. Case presentation A 55-year-old male with NB secondary to SCI contributed 12 urine samples over an 8-month period during asymptomatic, symptomatic, and postantibiotic periods. All bacteria identified on culture were present on 16S rRNA sequencing, however, 16S rRNA sequencing revealed the presence of bacteria not isolated on culture. In particular, Burkholderia fungorum was present in three samples during both asymptomatic and symptomatic periods. White blood cells of ≥5-10/high power field and leukocyte esterase ≥2 on urinalysis was associated with the presence of symptoms. Discussion In this patient, there was a predominance of pathogenic bacteria and a lack of putative probiotic bacteria during both symptomatic and asymptomatic states. Urinalysis-defined inflammatory markers were present to a greater extent during symptomatic periods compared to the asymptomatic state, which may underscore a role for urinalysis or other inflammatory markers in differentiating asymptomatic bacteriuria from UTI in patients with NB. The finding of potentially pathogenic bacteria identified by sequencing but not cultivation, suggests a need for greater understanding of the relationships amongst bacterial species in the bacteriuric neuropathic bladder.

No abstract

No abstract

No abstract