Nonclinical pharmacokinetics and biodistribution of VSV-GP using methods to decouple input drug disposition and viral replication.

Viral replication places oncolytic viruses (OVs) in a unique niche in the field of drug pharmacokinetics (PK) as their self-amplification obscures exposure-response relationships. Moreover, standard bioanalytical techniques are unable to distinguish the input from replicated drug products. Here, we combine two novel approaches to characterize PK and biodistribution (BD) after systemic administration of vesicular stomatitis virus pseudotyped with lymphocytic choriomeningitis virus glycoprotein (VSV-GP) in healthy mice. First: to decouple input drug PK/BD versus replication PK/BD, we developed and fully characterized a replication-incompetent tool virus that retained all other critical attributes of the drug. We used this approach to quantify replication in blood and tissues and to determine its impact on PK and BD. Second: to discriminate the genomic and antigenomic viral RNA strands contributing to replication dynamics in tissues, we developed an in situ hybridization method using strand-specific probes and assessed their spatiotemporal distribution in tissues. This latter approach demonstrated that distribution, transcription, and replication localized to tissue-resident macrophages, indicating their role in PK and BD. Ultimately, our study results in a refined PK/BD profile for a replicating OV, new proposed PK parameters, and deeper understanding of OV PK/BD using unique approaches that could be applied to other replicating vectors.

Uropathogenic Escherichia coli-induced fibrosis, leading to lower urinary tract symptoms, is associated with type 2 cytokine signaling.

Chronic inflammation and prostate fibrosis have been identified as contributors to lower urinary tract symptoms (LUTS) pathophysiology in humans. It has been shown that transurethral infection of an Escherichia coli strain named CP1, which was isolated from a patient with chronic prostatitis, can lead to the develop of differential chronic inflammation and pain in certain mouse strains. Therefore, we hypothesized that differential inflammation would influence fibrotic response in the prostate. This study showed that while prostatic infection by CP1 causes the development of chronic tactile allodynia in NOD/ShiltJ (NOD) but not C57BL/6 (B6) mice, both mice developed evidence of prostate inflammation, prostate fibrosis, and urinary dysfunction. Fibrosis was confirmed by the upregulation of fibrosis-associated messenger RNAs (mRNAs), α-smooth muscle actin immunohistochemistry, and collagen staining with picrosirius red. These findings were mainly focused on the dorsolateral lobes of the prostate. Both mouse strains also developed smaller, more frequent voiding patterns postinfection, examined via cystometry. B6 mice responded to CP1 infection with type 2 cytokines (IL-4 and IL-13), while NOD mice did not, which may explain the differing tactile allodynia responses and level of collagen deposition. When mice lacking signal transducer and activator of transcription 6 (STAT6), a transcription factor known to be important for the production and signaling of IL-4 and IL-13, were infected with CP1, fibrosis was attenuated. This study provides a potential model for studying the development of infection-induced prostatic fibrosis and LUTS. This study also demonstrates that CP1-induced prostate fibrosis has a STAT6-dependent mechanism in B6 mice.