Paper Highlights
Kurthkoti et al. 2017. The Capacity of Mycobacterium tuberculosis To Survive Iron Starvation Might Enable It To Persist in Iron-Deprived Microenvironments of Human Granulomas.
One-third of the world population may harbor persistent M. tuberculosis, causing an asymptomatic infection that is refractory to treatment and can reactivate to become potentially lethal tuberculosis disease. However, little is known about the factors that trigger and maintain M. tuberculosis persistence in infected individuals. Iron is an essential nutrient for M. tuberculosis growth. In this study, we show, first, that in human granulomas the immune defense creates microenvironments in which M. tuberculosis likely experiences drastic Fe deprivation and, second, that Fe-starved M. tuberculosis is capable of long-term persistence without growth. Together, these observations suggest that Fe deprivation in the lung might trigger a state of persistence in M. tuberculosis and promote chronic TB. We also identified vulnerabilities of iron-restricted persistent M. tuberculosis,which can be exploited for the design of new antitubercular therapies.
Kurthkoti K, Amin H, Marakalala MJ, Ghanny S, Subbian S, Sakatos A, Livny J, Fortune SM, Berney M, Rodriguez GM (2017) The Capacity of Mycobacterium tuberculosis To Survive Iron Starvation Might Enable It To Persist in Iron-Deprived Microenvironments of Human Granulomas. MBio 8. PMI: 28811344
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Arrigucci et al. 2017. FISH-Flow, a protocol for the concurrent detection of mRNA and protein in single cells using fluorescence in situ hybridization and flow cytometry.
This Nature Method manuscript describes a flow-cytometry-based protocol for intracellular mRNA measurements in nonadherent mammalian cells using fluorescence in situ hybridization (FISH) probes. The method, which is called FISH-Flow, allows for high-throughput multiparametric measurements of gene expression, a task that was not feasible with earlier, microscopy-based approaches. The FISH-Flow protocol involves cell fixation, permeabilization and hybridization with a set of fluorescently labeled oligonucleotide probes. In this protocol, surface and intracellular protein markers can also be stained with fluorescently labeled antibodies for simultaneous protein and mRNA measurement. Moreover, a semiautomated, single-tube version of the protocol can be performed with a commercially available cell-wash device that reduces cell loss, operator time and interoperator variability. It takes ~30 h to perform this protocol. An example of FISH-Flow measurements of cytokine mRNA induction by ex vivo stimulation of primed T cells with specific antigens is described.
Arrigucci R, Bushkin Y, Radford F, Lakehal K, Vir P, Pine R, Martin D, Sugarman J, Zhao Y, Yap GS, Lardizabal AA, Tyagi S, Gennaro ML (2017) FISH-Flow, a protocol for the concurrent detection of mRNA and protein in single cells using fluorescence in situ hybridization and flow cytometry. Nat Protoc 12: 1245-1260. PMI: 28518171
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Vinnard C et al. 2017. Long-term Mortality of Patients With Tuberculous Meningitis in New York City: A Cohort Study.
Tuberculosis meningitis (TBM) is the most devastating clinical presentation of infection with M. tuberculosis; delayed initiation of effective anti-tuberculosis (TB) therapy is associated with poor treatment outcomes. Our objective was to determine the relationship between drug resistance and 10-year mortality among TBM patients. We conducted a retrospective cohort study of patients with culture-confirmed TBM reported to the TB registry in New York City, NY (US) between January 1, 1992 and December 31, 2001. Date of death was ascertained by matching the TB registry with death certificate data for 1992 through 2012 from the New York Office of Vital Statistics. Among TBM patients without rifampin-resistant isolates, isoniazid resistance was associated with mortality after the first 60 days of treatment when controlling for age and HIV infection (adjusted HR 2.77, 95% CI: 1.28-6.01). We observed rapid early mortality in patients with rifampin-resistant isolates, and an independent association between isoniazid-resistant isolates and death after the first 60 days of therapy. These findings support the continued evaluation of rapid diagnostic techniques and the empiric addition of second-line drugs for patients with clinically suspected drug-resistant TBM.
Vinnard C, King L, Munsiff S, Crossa A, Iwata K, Pasipanodya J, Proops D, Ahuja S (2016) Long-term Mortality of Patients With Tuberculous Meningitis in New York City: A Cohort Study. Clin Infect Dis. PMI: 27927856
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