Androgen receptor inhibition suppresses anti-tumor neutrophil response against bone metastatic prostate cancer via regulation of TβRI expression.

Bone metastatic disease of prostate cancer (PCa) is incurable and progression in bone is largely dictated by tumor-stromal interactions in the bone microenvironment. We showed previously that bone neutrophils initially inhibit bone metastatic PCa growth yet metastatic PCa becomes resistant to neutrophil response. Further, neutrophils isolated from tumor-bone lost their ability to suppress tumor growth through unknown mechanisms.

Modified chitosan for effective renal delivery of siRNA to treat acute kidney injury.

Acute kidney injury (AKI) is characterized by a sudden decrease in renal function and impacts growing number of people worldwide. RNA interference (RNAi) showed potential to treat diseases with no or limited conventional therapies, including AKI. Suitable carriers are needed to protect and selectively deliver RNAi to target cells to fully explore this therapeutic modality.

Dually Active Polycation/miRNA Nanoparticles for the Treatment of Fibrosis in Alcohol-Associated Liver Disease.

Alcohol-associated liver disease (AALD) is a major cause of liver disorders worldwide. Current treatment options are limited, especially for AALD-associated fibrosis. Promising approaches include RNA interference for miR-155 overexpression in Kupffer cells (KCs), as well as the use of CXCR4 antagonists that inhibit the activation of hepatic stellate cells (HSCs) through the CXCL12/CXCR4 axis.

Machine learning analyses of highly-multiplexed immunofluorescence identifies distinct tumor and stromal cell populations in primary pancreatic tumors.

Background: Pancreatic ductal adenocarcinoma (PDAC) is a formidable challenge for patients and clinicians.

Objective: To analyze the distribution of 31 different markers in tumor and stromal portions of the tumor microenvironment (TME) and identify immune cell populations to better understand how neoplastic, non-malignant structural, and immune cells, diversify the TME and influence PDAC progression.

Methods: Whole slide imaging (WSI) and cyclic multiplexed-immunofluorescence (MxIF) was used to collect 31 different markers over the course of nine distinctive imaging series of human PDAC samples.

Collagen fiber regulation in human pediatric aortic valve development and disease.

Congenital aortic valve stenosis (CAVS) affects up to 10% of the world population without medical therapies to treat the disease. New molecular targets are continually being sought that can halt CAVS progression. Collagen deregulation is a hallmark of CAVS yet remains mostly undefined.

Targeting the Tumor Core: Hypoxia-Responsive Nanoparticles for the Delivery of Chemotherapy to Pancreatic Tumors.

In pancreatic ductal adenocarcinoma (PDAC), early onset of hypoxia triggers remodeling of the extracellular matrix, epithelial-to-mesenchymal transition, increased cell survival, the formation of cancer stem cells, and drug resistance. Hypoxia in PDAC is also associated with the development of collagen-rich, fibrous extracellular stroma (desmoplasia), resulting in severely impaired drug penetration. To overcome these daunting challenges, we created polymer nanoparticles (polymersomes) that target and penetrate pancreatic tumors, reach the hypoxic niches, undergo rapid structural destabilization, and release the encapsulated drugs.

Human Islet Response to Selected Type 1 Diabetes-Associated Bacteria: A Transcriptome-Based Study.

Type 1 diabetes (T1D) is a chronic autoimmune disease that results from destruction of pancreatic β-cells. T1D subjects were recently shown to harbor distinct intestinal microbiome profiles. Based on these findings, the role of gut bacteria in T1D is being intensively investigated.

Inhibition of geranylgeranyl diphosphate synthase is a novel therapeutic strategy for pancreatic ductal adenocarcinoma.

Rab proteins play an essential role in regulating intracellular membrane trafficking processes. Rab activity is dependent upon geranylgeranylation, a post-translational modification that involves the addition of 20-carbon isoprenoid chains via the enzyme geranylgeranyl transferase (GGTase) II. We have focused on the development of inhibitors against geranylgeranyl diphosphate synthase (GGDPS), which generates the isoprenoid donor (GGPP), as anti-Rab agents.

Aminoglycosides rapidly inhibit NAD(P)H metabolism increasing reactive oxygen species and cochlear cell demise.

Despite causing permanent hearing loss by damaging inner ear sensory cells, aminoglycosides (AGs) remain one of the most widely used classes of antibiotics in the world. Although the mechanisms of cochlear sensory cell damage are not fully known, reactive oxygen species (ROS) are clearly implicated. Mitochondrial-specific ROS formation was evaluated in acutely cultured murine cochlear explants exposed to gentamicin (GM), a representative ototoxic AG antibiotic.

Met receptor inhibitor SU11274 localizes in the endoplasmic reticulum.

We discovered that SU11274, a class I c-Met inhibitor, fluoresces when excited by 488 nm laser light and showed rapid specific accumulation in distinct subcellular compartments. Given that SU11274 reduces cancer cell viability, we exploited these newly identified spectral properties to determine SU11274 intracellular distribution and accumulation in human pancreatic cancer cells. The aim of the studies reported here was to identify organelle(s) to which SU11274 is trafficked.

Gentamicin differentially alters cellular metabolism of cochlear hair cells as revealed by NAD(P)H fluorescence lifetime imaging.

Aminoglycoside antibiotics are implicated as culprits of hearing loss in more than 120,000 individuals annually. Research has shown that the sensory cells, but not supporting cells, of the cochlea are readily damaged and/or lost after use of such antibiotics. High-frequency outer hair cells (OHCs) show a greater sensitivity to antibiotics than high- and low-frequency inner hair cells (IHCs).

Gentamicin rapidly inhibits mitochondrial metabolism in high-frequency cochlear outer hair cells.

Aminoglycosides (AG), including gentamicin (GM), are the most frequently used antibiotics in the world and are proposed to cause irreversible cochlear damage and hearing loss (HL) in 1/4 of the patients receiving these life-saving drugs. Akin to the results of AG ototoxicity studies, high-frequency, basal turn outer hair cells (OHCs) preferentially succumb to multiple HL pathologies while inner hair cells (IHCs) are much more resilient. To determine if endogenous differences in IHC and OHC mitochondrial metabolism dictate differential sensitivities to AG-induced HL, IHC- and OHC-specific changes in mitochondrial reduced nicotinamide adenine dinucleotide (NADH) fluorescence during acute (1 h) GM treatment were compared.

The roles of conserved and nonconserved cysteinyl residues in the oligomerization and function of mammalian prestin.

The creation of several prestin knockout and knockin mouse lines has demonstrated the importance of the intrinsic outer hair cell membrane protein prestin to mammalian hearing. However, the structure of prestin remains largely unknown, with even its major features in dispute. Several studies have suggested that prestin forms homo-oligomers that may be stabilized by disulfide bonds.

MicroRNA-183 family expression in hair cell development and requirement of microRNAs for hair cell maintenance and survival.

MicroRNAs (miRNAs) post-transcriptionally repress complementary target gene expression and can contribute to cell differentiation. The coordinate expression of miRNA-183 family members (miR-183, miR-96, and miR-182) has been demonstrated in sensory cells of the mouse inner ear and other vertebrate sensory organs. To further examine hair cell miRNA expression in the mouse inner ear, we have analyzed miR-183 family expression in wild type animals and various mutants with defects in neurosensory development.

A flow cytometric assay to quantify in vivo bacterial uptake by alveolar macrophages.

Our laboratory has developed a flow cytometric assay to quantify alveolar macrophage (Mcapital EF, Cyrillic) phagocytosis of bacteria within a live animal. Mcapital EF, Cyrillics collected by bronchoalveolar lavage from rats infected transtracheally with Syto 9-labeled bacteria are fluorescently labeled for identification and analyzed by flow cytometry to quantify their bacterial uptake.

Fluorescence microscopy methods in the study of protein structure and function.

As more and more proteins specific to hair cells are discovered, it becomes imperative to understand their structure and how that contributes to their function. The fluorescence microscopic methods described here can be employed to provide information on protein-protein interactions, whether homomeric or heteromeric, and on protein conformation. Here, we describe two fluorescence microscopic methodologies applied to the outer hair cell-specific membrane protein prestin: the intensity and fluorescence lifetime (FLIM) variants of FRET (Fluorescence Resonance Energy Transfer), used in the study of protein-protein interactions, and the Scanning Cysteine Accessibility Method (SCAM), used for the determination of protein conformation.

Localization of betav tubulin in the cochlea and cultured cells with a novel monoclonal antibody.

Tubulin, the dimeric structural protein of microtubules, is a heterodimer of alpha and beta subunits; both alpha and beta exist as numerous isotypes encoded by different genes. In vertebrates the sequence differences among the beta(I), beta(II), beta(III), beta(IV) and beta(V) isotypes are highly conserved in evolution, implying that the isotypes may have functional significance. Isotype-specific monoclonal antibodies have been useful in determining the cellular and sub-cellular distributions and possible functions of the beta(I), beta(II), beta(III), and beta(IV) isotypes; however, little is known about the beta(V) isotype.

Long-distance three-color neuronal tracing in fixed tissue using NeuroVue dyes.

Dissecting development of neuronal connections is critical for understanding neuronal function in both normal and diseased states. Charting the development of the multitude of connections is a monumental task, since a given neuron typically receives hundreds of convergent inputs from other neurons and provides divergent outputs for hundreds of other neurons. Although progress is being made utilizing various mutants and/or genetic constructs expressing fluorescent proteins like GFP, substantial work remains before a database documenting the development and final location of the neuronal pathways in an adult animal is completed.

Lateral wall protein content mediates alterations in cochlear outer hair cell mechanics before and after hearing onset.

Specialized outer hair cells (OHCs) housed within the mammalian cochlea exhibit active, nonlinear, mechanical responses to auditory stimulation termed electromotility. The extraordinary frequency resolution capacity of the cochlea requires an exquisitely equilibrated mechanical system of sensory and supporting cells. OHC electromotile length change, stiffness, and force generation are responsible for a 100-fold increase in hearing sensitivity by augmenting vibrational input to non-motile sensory inner hair cells.

Cell type-specific reduction of beta tubulin isotypes synthesized in the developing gerbil organ of Corti.

There are seven isotypic forms of the microtubule protein beta tubulin in mammals, but not all isotypes are synthesized in every cell type. In the adult organ of Corti, each of the five major cell types synthesizes a different subset of isotypes. Inner hair cells synthesize only betaI and betaII tubulin, while outer hair cells make betaI and betaIV tubulin.

Selective expression of beta tubulin isotypes in gerbil vestibular sensory epithelia and neurons.

The seven mammalian isotypes of beta tubulin are strikingly similar in amino acid sequence. The differences in isotypic sequence, although small, are nonetheless conserved in evolution, which suggests that they may confer distinct functional roles. If so, such roles should be reflected in the selective expression of isotypes by cell type, or even in the sorting of isotypes to within-cell pools.

Requirement for the betaI and betaIV tubulin isotypes in mammalian cilia.

Nielsen et al., [2001: Curr Biol 11:529-533], based on studies in Drosophila, have proposed that beta tubulin in axonemal microtubules must contain a specific acidic seven amino acid sequence in its carboxyl terminus. In mammals, the two betaIV isotypes (betaIVa and betaIVb) contain that sequence.

Differential synthesis of beta-tubulin isotypes in gerbil nasal epithelia.

Compartmentalization of beta-tubulin isotypes within cells according to function was examined in gerbil olfactory and respiratory epithelia by using specific antibodies to four beta-tubulin isotypes (beta(I), beta(II), beta(III), and beta(IV)). Isotype synthesis was cell-type-specific, but the localization of the isotypes was not compartmentalized. All four isotypes were found in the cilia, dendrites, somata, and axons of olfactory neurons.