Use this URL to cite or link to this record in EThOS:
Title: Identification of a ciliary defect associated with pulmonary nontuberculous mycobacterial disease
Author: Fowler, Cedar
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2013
Availability of Full Text:
Access from EThOS:
Full text unavailable from EThOS. Please try the link below.
Access from Institution:
Over the past several decades, the rate of pulmonary nontuberculous my- cobacterial (PNTM) disease has been increasing. PNTM patients gener- ally consist of lean and tall women presenting with symptoms in the sixth decade of life. They have a de nitive morphophenotype, but no consistent immunological abnormalities despite extensive investigation. I hypothesized that respiratory epithelial dysfunction might play a critical role in PNTM disease predisposition because diseases with defects of mucociliary transport have high rates of PNTM disease that increase with age, suggesting a direct connection between airway epithelial function and PNTM disease. I found that PNTM patients have a distinct respiratory epithelial phenotype ex vivo and decreased nasal nitric oxide levels in vivo. The PNTM ex vivo phenotype consists of an abnormally low resting ciliary beat frequency (CBF) and abnormal CBF response to toll-like receptor (TLR) agonists. The depressed baseline CBF response in PNTM patient cells can be normalized ex vivo by augmenting the nitric oxide-cyclic guanosine monophosphate pathway without appreciable e ect on CBF in healthy controls. In healthy controls, bacterial TLR agonists increase CBF and viral TLR agonists decrease CBF. In PNTM patients these responses are impaired and are not normalized with the normalization of the resting CBF rate. Inhibitor-induced disruption of signalling pathways associated with CBF regulation demonstrated that the majority of the CBF response to TLR agonists involves the PI-3K pathway and PKC. Inhibition of the PI-3K pathway (PI-3K , Akt1, and PDK1) closely mimicked the ex vivo phenotype seen in PNTM patient respiratory epithelia. These data identify a novel aspect of PNTM disease with in vivo and ex vivo correlates that suggest that PNTM infection is associated with abnormal function at both the CBF and TLR response levels. This phenotype is novel, reproducible, and provide a foundation with which to determine the genetic basis of PNTM infection.
Supervisor: Not available Sponsor: National Institutes of Health ; National Institute of Allergy and Infectious Diseases
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
Keywords: Toll-Like Receptors ; Cilia ; Nontuberculous Mycobacterium Infections ; Nitric Oxide ; Lung Disease ; Respiratory Mucosa ; Female ; Human ; Ciliary Beat Frequency ; PI-3K ; Sildenafil ; Primary Ciliary Dyskensia ; Cystic Fibrosis ; AKT