Faculty Bibliography

BACKGROUND: One of the major constraints in elucidating the mechanisms involved in the etiology of benign prostatic hyperplasia (BPH) is the lack of suitable model systems that are readily manipulable in vitro and in vivo. To address this issue, we have used murine prostatic cell lines to establish a novel in vivo model for studying prostatic cell interactions. METHODS: Luminal, basal, and smooth muscle (SM) cell lines were inoculated alone or in combinations under the renal capsule of intact or castrated male mice, and the growth and composition of prostatic tissue in the absence or presence of doxazosin was determined. RESULTS: Both the luminal and basal cell lines reconstituted prostatic tissue if co-inoculated under the renal capsule with normal SM cells, whereas none of the lines formed significant tissue when inoculated alone. Luminal cells produced and secreted prostatic secretory products. The growth of prostatic tissue formed from co-inoculation of basal and SM cells was androgen responsive. In addition, a significant reduction in prostatic tissue was noted in animals treated with doxazosin. CONCLUSION: We have established an in vivo model that uses prostatic epithelial and SM cell lines for investigating cellular interactions between epithelial and SM cells that regulate prostatic growth and function. This model will be useful for delineating the mechanisms by which prostatic cells interact and in determining the efficacy of new approaches aimed at interfering with prostatic stromal/epithelial interactions that result in abnormal cellular proliferation

Carcinoma in situ (CIS) of the bladder has recently been proposed to be a heterogeneous group of diseases with varied histogenesis and biological behavior. In this study, we describe the sequential steps of CIS development and progression in a transgenic mouse model expressing low levels of the SV40 large T antigen. We found that CIS in transgenic mice arose from urothelial dysplasia, that CIS could persist for an extended period of time without invasion, and that the majority of CIS eventually evolved into high-grade, superficial, papillary tumors before a small fraction of them advanced to invasion/metastasis. A genome-wide search of chromosomal imbalances by comparative genomic hybridization revealed that 9 of 11 (82%) of CIS had losses on chromosome 11. Southern blotting demonstrated the allelic loss of the p53 gene, which resides on mouse chromosome 11, in four comparative genomic hybridization-tested tumors and 10 of 11 (91%) additional CIS examined. Consistent with the reduced p53 gene dosage because of the allelic loss and the functional inactivation of p53 protein of the remaining allele by SV40T antigen, there was a dramatic decrease in CIS of Mdm-2, a major p53 target. In contrast, the level of p21, another p53 target, was largely unaltered, suggesting that p21 expression can be regulated by p53-independent mechanisms. These results delineate the early stages of bladder tumorigenesis and suggest that the loss of a p53-bearing chromosome is an early event in bladder tumorigenesis and is crucial for the genesis and the maintenance, but not the progression, of bladder CIS. On the basis of our current and previous transgenic studies, we have proposed an integrated pathway progression model of bladder cancer

Our laboratory's recent observations that transcriptionally inactive phosphoprotein (P) mutants can efficiently function in replicating vesicular stomatitis virus (VSV) defective interfering particle in a three-plasmid-based (L, P, and N) reverse genetics system in vivo (A. K. Pattnaik, L. Hwang, T. Li, N. Englund, M. Mathur, T. Das, and A. K. Banerjee, J. Virol. 71:8167-8175, 1997) led us to propose that a tripartite complex consisting of L-(N-P) protein may represent the putative replicase for synthesis of the full-length genome RNA. In this communication we demonstrate that such a complex is indeed detectable in VSV-infected BHK cells. Furthermore, coexpression of L, N, and P proteins in Sf21 insect cells by recombinant baculovirus containing the respective genes also resulted in the formation of a tripartite complex, as shown by immunoprecipitation with specific antibodies. A basic amino acid mutant of P protein, P260A, previously shown to be inactive in transcription but active in replication (T. Das, A. K. Pattnaik, A. M. Takacs, T. Li, L. N. Hwang, and A. K. Banerjee, Virology 238:103-114, 1997) was also capable of forming the mutant [L-(N-Pmut)] complex in both insect cells and BHK cells. Sf21 extract containing either the wild-type P protein or the mutant P protein along with the L and N proteins was capable of synthesizing 42S genome-sense RNA in an in vitro replication reconstitution reaction. Addition of N-Pmut or wild-type N-P complex further stimulated the synthesis of the genome-length RNA. These results indicate that the transcriptase and replicase complexes of VSV are possibly two distinct entities involved in carrying out capped mRNAs and uncapped genome and antigenome RNAs, respectively.

Polarized cells contain numerous membrane domains, but it is unclear how the formation of these domains is coordinated to create a single integrated cell architecture. Genetic screens of Drosophila melanogaster embryos have identified three complexes, each containing one of the PDZ domain proteins--Stardust (Sdt), Bazooka (Baz) and Scribble (Scrib)--that control epithelial polarity and formation of zonula adherens. We find that these complexes can be ordered into a single regulatory hierarchy that is initiated by cell adhesion-dependent recruitment of the Baz complex to the zonula adherens. The Scrib complex represses apical identity along basolateral surfaces by antagonizing Baz-initiated apical polarity. The Sdt-containing Crb complex is recruited apically by the Baz complex to counter antagonistic Scrib activity. Thus, a finely tuned balance between Scrib and Crb complex activity sets the limits of the apical and basolateral membrane domains and positions cell junctions. Our data suggest a model in which the maturation of epithelial cell polarity is driven by integration of the sequential activities of PDZ-based protein complexes

BACKGROUND: Acute dacryoadenitis is an uncommon disease. CASE: We present what we believe to be the first reported case of herpes zoster ophthalmicus with the onset of acute dacryoadenitis. OBSERVATIONS: A 30-year-old man complained of severe ocular pain and hyperemia in his right eye. Magnetic resonance imaging (MRI) demonstrated enlargement of the right lacrimal gland and acute dacryoadenitis was diagnosed. Two days after treatment with systemic antibiotics he developed iridocyclitis and skin lesions confined to the first division of the trigeminal nerve; therefore, herpes zoster ophthalmicus was diagnosed. Treatment with acyclovir immediately resolved the ocular pain and swelling of the upper eyelid. MRI conducted in the 4 months after the initial examination showed there was no longer enlargement of the right lacrimal gland. CONCLUSION: Clinicians should be aware that varicella-zoster virus may cause acute dacryoadenitis.

Clostridial botulinum neurotoxins (BoNTs) abort the process of neurotransmitter release at presynaptic motor nerve terminals, causing muscle paralysis. An enigmatic step in the intoxication process is the mechanism by which the neurotoxin heavy chain (HC) forms the conduit for the translocation of the light chain (LC) protease across the endosomal membrane into the cytosol, its site of action. Here we investigate the mechanism of LC translocation by using the combined detection of channel currents and substrate proteolysis, the two hallmark activities of BoNT. Our data are consistent with the translocation of the LC through the HC channel and show that the LC protease activity is retrieved in the trans compartment after translocation. We propose that the BoNT HC-LC complex embedded in the membrane is a transmembrane chaperone, a dynamic structural device that prevents aggregation and achieves translocation of the LC. In this regard, the complex is similar to the protein conducting/translocating channels of the endoplasmic reticulum, mitochondria and chloroplasts.