Tamm-Horsfall protein augments neutrophil NETosis during urinary tract infection

Urinary neutrophils are a hallmark of urinary tract infection (UTI), yet the mechanisms governing their activation, function, and efficacy in controlling infection remain incompletely understood. Tamm-Horsfall glycoprotein (THP), the most abundant protein in urine, uses terminal sialic acids to bind an inhibitory receptor and dampen neutrophil inflammatory responses. We hypothesized that neutrophil modulation is an integral part of THP-mediated host protection. In a UTI model, THP-deficient mice showed elevated urinary tract bacterial burdens, increased neutrophil recruitment, and more severe tissue histopathological changes compared to WT mice. Furthermore, THP-deficient mice displayed impaired urinary NETosis during UTI. To investigate the impact of THP on NETosis, we coupled in vitro fluorescence-based NET assays, proteomic analyses, and standard and imaging flow cytometry with peripheral human neutrophils. We found that THP increases proteins involved in respiratory chain, neutrophil granules, and chromatin remodeling pathways, enhances NETosis in an ROS-dependent manner, and drives NET-associated morphologic features including nuclear decondensation. These effects were observed only in the presence of a NETosis stimulus and could not be solely replicated with equivalent levels of sialic acid alone. We conclude that THP is a critical regulator of NETosis in the urinary tract, playing a key role in host defense against UTI.

Molecular dissection and testing of PRSS37 function through LC-MS/MS and the generation of a PRSS37 humanized mouse model

The quest for a non-hormonal male contraceptive pill for men still exists. Serine protease 37 (PRSS37) is a sperm-specific protein that when ablated in mice renders them sterile. In this study we sought to examine the molecular sequelae of PRSS37 loss to better understand its molecular function, and to determine whether human PRSS37 could rescue the sterility phenotype of knockout (KO) mice, allowing for a more appropriate model for drug molecule testing. To this end, we used CRISPR-EZ to create mice lacking the entire coding region of Prss37, used pronuclear injection to create transgenic mice expressing human PRSS37, intercrossed these lines to generate humanized mice, and performed LC-MS/MS of KO and control tissues to identify proteomic perturbances that could attribute a molecular function to PRSS37. We found that our newly generated Prss37 KO mouse line is sterile, our human transgene rescues the sterility phenotype of KO mice, and our proteomics data not only yields novel insight into the proteome as it evolves along the male reproductive tract, but also demonstrates the proteins significantly influenced by PRSS37 loss. In summary, we report vast biological insight including insight into PRSS37 function and the generation of a novel tool for contraceptive evaluation.

Abstract 3922: Proteomic profiling of muscle invasive bladder cancer

Background: Only one quarter of patients with muscle invasive urothelial bladder cancer (MIBC) gain approximately 5% improvement in 5-year overall survival from cisplatin-based neoadjuvant chemotherapy (NAC). For patients with residual invasive cancer post radical cystectomy there is no standard of care and high mortality. Previous TCGA projects focused on pre-NAC MIBC genomic and transcriptomic alterations and identified 5 molecular subtypes with differential risk and response. For this study we hypothesized that comprehensive proteomic and phosphoproteomic profiling of MIBC prior to NAC will further define mechanisms responsible for chemotherapy resistance, and identify specific and actionable targeted therapies for patients with NAC-resistant tumors.

Methods: OCT-embedded and flash frozen tissue samples from 143 eligible patients were processed and tested for proteomics quality control (QC). Samples containing >45% tumor content, less than 10% muscle content and >2,000 protein identifications in a single-shot quality control assay were selected for deep-scale proteomic and phosphoproteomic profiling. A final cohort of 60 samples (52 pre-treatment and 8 patient-matched post-treatment tumors) were multiplexed using tandem mass tags (TMT-11), fractionated by basic reverse phase chromatography and analyzed by liquid chromatography and mass spectrometry (LC-MS).

Results: Over 12,000 proteins were identified in total, and 8,353 proteins identified in all samples, including 425 kinases and 77 targets of FDA approved cancer therapies. Principal component analysis identified two distinct resistant clusters and one sensitive cluster. The samples were clustered based on the 5 TCGA subtypes which resulted in the sub stratification of the resistant clusters into two resistance-enriched basal-squamous clusters (BS1 and BS2 respectively), one infiltrated-luminal cluster (L1), one sensitive luminal cluster (L2) and one intermediary cluster (L3) (with 86% samples resistant). UV response, Epithelial to Mesenchymal transition and Myogenesis were significantly elevated in both L1 and L3 (resistant) relative to L2 (sensitive). Similar, these pathways are significantly altered in L1 relative to L3. EGFR, CDK6, ITPKC and CSNK1 were elevated in the B4 subtype, all of which are potentially druggable targets. Matched samples and phosphoproteomics data will be presented.

Conclusion: Surrounding non-tumor tissue can obfuscate true tumor signatures in MIBC, cohort selection through stringent pathologic QC allows proteomic profiling to identify tumor features that correlate with NAC resistance. This dataset provides proof of principle that actionable targets and subtype distinctions can be identified through discovery proteomics and further analysis in NAC treated cohorts are justified.

Citation Format: Matthew V. Holt, Meggie N. Young, Karoline Kremers, Alexander Saltzman, Antrix Jain, Mei Leng, Hugo Villanueva, Lacey E. Dobrolecki, Beom-Jun Kim, Meenakshi Anurag, Matthew J. Ellis, Anna Malovannaya, Seth P. Lerner. Proteomic profiling of muscle invasive bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3922.

Intestinal Deletion of 3-Hydroxy-3-Methylglutaryl-Coenzyme A Reductase Promotes Expansion of the Resident Stem Cell Compartment

BACKGROUND

The intestine occupies the critical interface between cholesterol absorption and excretion. Surprisingly little is known about the role of de novo cholesterol synthesis in this organ, and its relationship to whole body cholesterol homeostasis. Here, we investigate the physiological importance of this pathway through genetic deletion of the rate-limiting enzyme.

METHODS

Mice lacking 3-hydroxy-3-methylglutaryl-coenzyme A reductase (Hmgcr) in intestinal villus and crypt epithelial cells were generated using a Villin-Cre transgene. Plasma lipids, intestinal morphology, mevalonate pathway metabolites, and gene expression were analyzed.

RESULTS

Mice with intestine-specific loss of Hmgcr were markedly smaller at birth, but gain weight at a rate similar to wild-type littermates, and are viable and fertile into adulthood. Intestine lengths and weights were greater relative to body weight in both male and female Hmgcr intestinal knockout mice. Male intestinal knockout had decreased plasma cholesterol levels, whereas fasting triglycerides were lower in both sexes. Lipidomics revealed substantial reductions in numerous nonsterol isoprenoids and sterol intermediates within the epithelial layer, but cholesterol levels were preserved. Hmgcr intestinal knockout mice also showed robust activation of SREBP-2 (sterol-regulatory element binding protein-2) target genes in the epithelium, including the LDLR (low-density lipoprotein receptor). At the cellular level, loss of Hmgcr is compensated for quickly after birth through a dramatic expansion of the stem cell compartment, which persists into adulthood.

CONCLUSIONS

Loss of Hmgcr in the intestine is compatible with life through compensatory increases in intestinal absorptive surface area, LDLR expression, and expansion of the resident stem cell compartment.

Multiplexed drug-based selection and counterselection genetic manipulations in Drosophila

The power of Drosophila melanogaster as a model system relies on tractable germline genetic manipulations. Despite Drosophila's expansive genetics toolbox, such manipulations are still accomplished one change at a time and depend predominantly on phenotypic screening. We describe a drug-based genetic platform consisting of four selection and two counterselection markers, eliminating the need to screen for modified progeny. These markers work reliably individually or in combination to produce specific genetic outcomes. We demonstrate three example applications of multiplexed drug-based genetics by generating (1) transgenic animals, expressing both components of binary overexpression systems in a single transgenesis step; (2) dual selectable and counterselectable balancer chromosomes; and (3) selectable, fluorescently tagged P[acman] bacterial artificial chromosome (BAC) strains. We perform immunoprecipitation followed by proteomic analysis on one tagged BAC line, demonstrating our platform's applicability to biological discovery. Lastly, we provide a plasmid library resource to facilitate custom transgene design and technology transfer to other model systems.

Partial loss of CFIm25 causes learning deficits and aberrant neuronal alternative polyadenylation

We previously showed that NUDT21-spanning copy-number variations (CNVs) are associated with intellectual disability (Gennarino et al., 2015). However, the patients' CNVs also included other genes. To determine if reduced NUDT21 function alone can cause disease, we generated Nudt21+/- mice to mimic NUDT21-deletion patients. We found that although these mice have 50% reduced Nudt21 mRNA, they only have 30% less of its cognate protein, CFIm25. Despite this partial protein-level compensation, the Nudt21+/- mice have learning deficits, cortical hyperexcitability, and misregulated alternative polyadenylation (APA) in their hippocampi. Further, to determine the mediators driving neural dysfunction in humans, we partially inhibited NUDT21 in human stem cell-derived neurons to reduce CFIm25 by 30%. This induced APA and protein level misregulation in hundreds of genes, a number of which cause intellectual disability when mutated. Altogether, these results show that disruption of NUDT21-regulated APA events in the brain can cause intellectual disability.

Abstract GS2-05: Microscaled proteogenomic methods for precision oncology

Cancer proteogenomics combines genomics, transcriptomics and mass spectrometry-based proteomics to gain insights into cancer biology and treatment responsiveness. While proteogenomics analyses have already shown great potential to deepen our understanding of cancer tissue complexity and signaling, how a patient’s tumor changes upon treatment has largely been the province of genomics. This is due to technical difficulties associated with doing proteogenomic analysis on clinic-derived core-needle biopsies. To address this critical need, we have developed a “microscaled” proteogenomics approach for tumor-rich OCT-embedded core needle biopsies. Tissue-sparing specimen processing (“Biopsy Trifecta EXTraction”, BioTExt) and microscaled proteomics (MiProt) methodologies allowed generation of deep-scale proteogenomics datasets, with copy number and transcript information for >20,000 genes and mass spectrometry-based identification and quantification of nearly all expressed proteins in a tumor (>10,000 proteins) and more than >20,000 phosphosites starting with just 25 micrograms of protein per sample. In order to understand the capabilities and limitations our our approach relative to more conventional deepscale proteomics requiring >10X more starting material, we compared preclinical patient derived xenograft (PDX) models at conventional scale with data obtained by core-needle biopsy of the same tissues. Comparable depth and biological insights were obtained from the cores relative to surgically resected tumors. As a proof-of-concept for implementation in clinical trials, we applied microscaled proteogenomic methods to a small-scale clinical study where biopsies were accrued from patients with ERBB2+ locally advanced breast cancer before and 48 to 72 hours after the first dose of neoadjuvant Trastuzumab-based chemotherapy. Multi-omics comparisons were conducted between samples associated with residual disease versus samples associated with complete pathological response. Integrative, microscaled proteogenomic analyses efficiently diagnosed the molecular bases of diverse candidate treatment resistance mechanisms including: 1) absence of ERBB2 amplification (false-ERBB2+); 2) insufficient ERBB2 activity for therapeutic sensitivity despite ERBB2 amplification (pseudo-ERBB2+); 3) resistance features in true-ERBB2+ cases including androgen receptor signaling, mucin expression and an inactive immune microenvironment; 4) lack of acute phospho-ERBB2 down-regulation in non-pCR cases. In summary, we have developed a robust proteogenomics pipeline well suited for large-scale cancer clinical studies to identify potential resistance mechanism in patients. We conclude that microscaled cancer proteogenomics could improve diagnostic precision in the clinical setting.

Citation Format: Shankha Satpathy, Eric Jaehnig, Krug Karsten, Beom-Jun Kim, Alexander Saltzman, Doug Chan, Kimberly Holloway, Meenakshi Anurag, Chen Huang, Purba Singh, Ari Gao, Noel Namai, Yongchao Dou, Bo Wen, Suhas Vasaikar, David Mutch, Mark Watson, Cynthia Ma, Foluso Ademuyiwa, Mothaffar Rimawi, Jeremy Hoog, Samuel Jacobs, Anna Malovannaya, Terry Hyslop, D.R Mani, Charles Perou, George Miles, Bing Zhang, Michael Gillette, Steven Carr, Matthew Ellis. Microscaled proteogenomic methods for precision oncology [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr GS2-05.

Abstract P5-08-01: DPYSL3 modulates mitosis, migration and epithelial to mesenchymal transition in claudin-low breast cancer

Proteogenomics is the field of integrating data from mass spectrometry-based shotgun proteomics, and phosphoproteomics into next-generation RNA and DNA sequencing data analysis pipelines that promises new insights into cancer biology and therapeutic targeting. As well as analyses of clinical samples for disease phenotype association analysis, the application of proteogenomics to model systems also has considerable potential. A Clinical Proteomic Tumor Analysis Consortium (CPTAC) proteogenomic analysis prioritized dihydropyrimidinase-like-3 (DPYSL3) as a multi-level (RNA/Protein/Phosphoprotein) expression outlier specific to the Claudin-Low (CLOW) subset of triple negative breast cancers. A Pubmed informatics tool indicated a paucity of data in the context of breast cancer which further prioritized DPYSL3 for study.

DPYSL3 was identified as a protein that is regulated during neuronal differentiation in the cerebral cortex and in neuronal cell lines and plays a role in regulating neurite outgrowth somehow through an association with vesicles in the growth cone. In addition, DPYSL3 expression has been observed in several malignant tumors, including prostate cancer, pancreatic cancer, gastric cancer and neuroblastoma. DPYSL3 is reported to play a role in cell migration and metastasis suppression in prostate cancer. However, in pancreatic cancer, DPYSL3 is positively associated with liver metastasis and poor outcome.

DPYSL3 knock-down in DPYSL3 (+) CLOW cell lines demonstrated reduced proliferation, yet enhanced motility and increased expression of Epithelial to Mesenchymal Transition (EMT) markers suggesting that DPYSL3 is a multi-functional signaling modulator. Slower proliferation in DPYSL3 (-) CLOW cells was associated with accumulation of multi-nucleated cells indicating a mitotic defect that was associated with a collapse of the vimentin (VIM) microfilament networkinduced by VIM hyperphosphorylation. On the other hand, DPYSL3 suppressed the expression of EMT regulators TWIST and SNAIL and opposed p21 activated kinase 2 (PAK2) dependent migration, but these EMT regulators in turn induced DPYSL3 expression, suggesting DPYSL3 participates in negative feedback in EMT. Cell migration in DPYSL3 (-) cells correlated with increased phosphorylation of PAK2 on Ser20 and was sensitive to PAK2 siRNA and pharmacological PAK inhibition.Immunoprecipitation and mass spectrometry-based proteomics or western blotting strongly suggests that PAKs interact such that DPYSL3 may function as a direct negative regulator of PAK family kinases. Thus, a PAK inhibitor could potentially mitigate increase migration as an adverse effect of DPYSL3 suppression.

In conclusion, DPYSL3 is a remarkable multifunctional signaling scaffold that should be examined further to provide insights into the stem cell-like state of claudin-low breast cancers, particularly in terms of their cell cycle dependencies, migratory activity and capacity for EMT.

Citation Format: Matsunuma R, Chan DW, Kim B-J, Singh P, Han A, Saltzman A, Cheng C, Lei JT, Sahin E, Leng M, Fan C, Perou CM, Malovannaya A, Ellis MJ. DPYSL3 modulates mitosis, migration and epithelial to mesenchymal transition in claudin-low breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-08-01.

Connections between the Anomalous Volumetric Properties of Alcohols in Aqueous Solution and the Volume of Hydrophobic Association

The partial molar volumes of alcohols in water exhibit a non-monotonic dependence on concentration at room temperature, initially decreasing with increasing concentration before passing through a minimum and rising to the pure liquid plateau. This anomalous behavior is associated with hydrophobic interactions. We report molecular simulations of short chain alcohols and alkanes in water to examine the volumetric properties of these mixtures at infinite dilution over a range of temperatures. Our simulations find this anomaly disappears at a crossover temperature, above which the solute volume only varies monotonically with concentration. A Voronoi volume analysis of solution configurations finds that solutes in clusters take up less space than individual solutes at low temperature and more space at elevated temperatures. These changes in cluster volumes are subsequently shown to correlate with the derivative of the solute partial molar volume with respect to solute concentration. The changes in solute volume upon nonpolar solute association impact the response of molecular-scale hydrophobic interactions for assembly with increasing pressure.

Communication: Stiffening of dilute alcohol and alkane mixtures with water

We probe the anomalous compressibilities of dilute mixtures of alcohols and alkane gases in water using molecular simulations. The response to increasing solute concentration depends sensitively on temperature, with the compressibility decreasing upon solute addition at low temperatures and increasing at elevated temperatures. The thermodynamic origin of stiffening is directly tied to the solute's partial compressibility, which is negative at low temperatures and rises above water's compressibility with increasing temperature. Hydration shell waters concurrently tilt towards clathrate-like structures at low temperatures that fade with heating. Kirkwood-Buff theory traces the solute's partial compressibility to changes in the solute-water association volume upon heating and incongruous packing of waters at the boundary between the more structured hydration shell and bulk water.

Understanding human dendritic cell biology through gene profiling

Dendritic cells are potent antigen presenting cells whose function has been associated with a variety of immunological disorders. Because of their relevance to human disease, extensive efforts have been made to gain a better understanding of their biology. One aspect of these efforts has been in the identification of pertinent molecules expressed in these cells through gene profiling experiments and proteomics. In this review, we summarize the results from the various profiling studies that have been done with human dendritic cells. We focus on molecules, which have been confirmed by other methods, such as quantitative PCR, or have been identified in multiple profiling studies to be expressed in the respective dendritic cell type. Through such profiling experiments and subsequent analysis, interesting molecules have been identified which can be further studied to determine their role in dendritic cell biology.

Pyridoxine (vitamin B6) toxicity: enhancement by uremia in rats

Pyridoxine is not completely innocuous. Large doses can cause a peripheral neuropathy despite renal excretion of this water-soluble vitamin. Renal failure patients are treated with pyridoxine to prevent a deficiency. The safety of pyridoxine treatment in the presence of renal dysfunction has not been studied. Our experiments on anephric rats show that the uremic state, in a mere 3 or 4 days, causes a 5- to 10-fold increase in susceptibility to pyridoxine-induced neuronopathy. These results suggest a need for caution in prescribing pyridoxine to uremic patients who will probably take the vitamin daily for many years.

Proliferation of glial cells induced by lithium in the neural lobe of the rat pituitary is enhanced by dehydration

Rats dehydrated by 6 days of water deprivation had a low level of mitotic activity in the astrocytes ('pituicytes') of the neural lobe of the pituitary. Mitotic activity in the pituicytes was greatly increased when isotonic lithium was administered in the last 3 days of water deprivation. Rehydration on the last day of the experiment produced a further increase in mitoses. Isotonic solutions of sodium, potassium or rubidium chloride did not increase mitoses. This model of cell proliferation is of interest because the mitotic activity is related to a physiological attempt to maintain homeostasis rather than a response to injury or the development of neoplasia.

Proliferation of glial cells in vivo induced in the neural lobe of the rat pituitary by lithium

Lithium salts are widely used for treatment of psychiatric illness. Lithium also affects cell proliferation. During investigation of the effect of lithium chloride on the central nervous system (CNS) of nephrectomized rats, we noted numerous mitotic figures in the neural lobe of the pituitary. Morphologic criteria established that the mitotic cells were astrocytes, the supporting glial cells of the CNS, also known as pituicytes. Equimolar doses of chlorides of chemically related cations (sodium, potassium, rubidium) had no such effect.

Prevention of chronic peritonitis caused by osmotic dysequilibrium in rats

OBJECTIVE AND DESIGN

This study was done to determine whether peritonitis caused by osmotic dysequilibrium could be prevented by pretreatment.

SUBJECTS

Young adult rats were used after induction of peritonitis by intraperitoneal injections of large volumes of pure water to create severe osmotic dysequilibrium.

TREATMENT

During the 1 or 2 weeks before induction of peritonitis, the rats were pretreated by intraperitoneal injections of small volumes of pure water or large volumes of moderately hypotonic electrolytes to produce a slight degree of osmotic dysequilibrium.

METHODS

Peritonitis was evaluated by macroscopic and microscopic study of peritoneal tissues.

RESULTS

The severity of peritonitis was greatly reduced by the pretreatments.

CONCLUSIONS

This study adds the peritoneum to the list of tissues in which adaptation to an injury can be accomplished by pretreatment with the same injurious agent, albeit in a less noxious form.

Peritoneal toxicity of water: a model of chronic peritonitis caused by osmotic dysequilibrium in rats

The purpose of this work was to determine whether the osmotic dysequilibrium created by intraperitoneal (i.p.) injection of pure water has any permanent, damaging toxic sequelae. Rats were injected i.p. with pure water on five successive days. Necropsies were performed 1 week after the last injection. Necropsies revealed fibrosis of peritoneal surfaces of liver and spleen, similar to the effects of chemical irritants but milder. The severity of the lesions depended on the dose of water and the number of injections. A few minutes of contact with pure water was sufficient to ensure subsequent development of fibrosis. Soon after the initial injury, the inoculum became less hypotonic and then isotonic. Isotonic or moderately hypotonic electrolyte solutions did not produce peritoneal fibrosis but very hypotonic solutions were toxic. Injection of the synthetic compound 48/80, which is known to cause discharge of mast cell granules, did not produce peritonitis, nor was contamination by endotoxin or by blood responsible for the lesions. Injection of water may be a useful method for investigating the role, if any, of mast cells and/or mesothelial cells in the toxic effects of osmotic dysequilibrium.

Are urea and creatinine uremic toxins in the rat?

Urea and creatinine are not generally considered to be important uremic toxins despite evidence from dialysis experiments to the contrary, and despite striking elevations of these nitrogenous waste products in uremia. In order to study this problem in acute uremia, we used a new dietary method for prolonging the survival of bilaterally nephrectomized rats. Urea or creatinine were injected on three successive days starting one day after the inception of uremia. Urea or creatinine injections shortened the survival time of acutely uremic rats, and increased the involution of thymus and spleen. The extra urea, but not creatinine, increased the serum osmolality. These data indicate that urea and creatinine are toxic in the acutely uremic rat. Hypertonicity of the serum may contribute to the toxicity of urea. Additional mechanisms of toxicity and additional toxins are not excluded.

Repeated toxic injury of peritoneum: accumulation of toxicity and adaptation to injury

In order to develop new methods for the study of pathogenesis of post-injury fibroplasia, a rat model of chemical peritonitis was explored. Sodium hypochlorite (NaOCl) of various concentrations was injected intraperitoneally one or more times using different intervals between doses. Some time later, the surface fibrosis of liver, spleen, omentum and other abdominal organs was evaluated. A dose-response relation at intermediate concentrations and an apparent threshold at low concentrations were observed. Fibroplasia was increased by repeated doses (accumulation) but it was ameliorated compared to the same total amount of chemical given as a single injection (adaptation during repeated dosing). The rapid disappearance of the chemical irritant and the large size and easy accessibility of the peritoneal cavity suggest that this model may be useful in further study of chemical toxicity and fibroplasia in relation to human fibrosing diseases and injuries (trauma, surgery, peritoneal dialysis). The model has the unique feature of evaluating the morphological effects of the toxic injury and secondary functional effects at the same time.

Feeding sugar overnight maintains metabolic homeostasis in rats and is preferable to overnight starvation

Rats are often starved overnight for many different reasons. Overnight starvation causes loss of body and liver weights, depletion of liver glycogen, decrease of blood glucose and loss of amino acids because of gluconeogenesis. Providing pure sucrose cubes as the sole overnight nutrient is a simple, inexpensive way to empty the gastrointestinal (GI) tract, while minimizing liver changes and preventing decrease of blood glucose and loss of amino acids. Adding sugars to the overnight drinking water as the sole nutrient has the same beneficial effects, provided the type of sugar and its concentration allow for sufficient intake and provided hyponatremia is avoided. Feeding sucrose cubes or sugar solutions will empty the gastrointestinal tract as effectively as starvation. In all instances, simple precautions against coprophagy and pica should be taken in order to secure optimal benefit.

Pertussis vaccine and pertussis toxin increase lithium levels in rats: possible role of G-proteins

A single dose of lithium was injected intravenously or intraperitoneally in rats. Lithium levels in serum and tissues 5 or 24 hours later were elevated when the rats were pretreated with pertussis vaccine (PV). The vaccine was effective whether given locally (subcutaneous) or systemically (intravenous). Tests of heated (inactivated) PV suggested that pertussis toxin might be responsible for the effects of PV. Injection of purified pertussis toxin (PT) confirmed this suggestion. Elevation of serum urea nitrogen suggested that lithium levels were increased because the combination of PV or PT with lithium reduced renal excretory function which could cause retention of lithium. Inasmuch as PV and PT are known to inactivate the inhibitory G-proteins, these data suggest G-protein involvement in the elevation of lithium levels by PV and PT.

Ascites produced in rats without tubercle bacilli or tumor cells

Intraperitoneal injection of rats with two doses of pertussis vaccine produces a small amount of ascitic fluid. Much larger amounts of fluid are produced when two spaced injections of the vaccine are preceded by a small amount of liquid petrolatum. A similar result is obtained by a single injection of pertussis vaccine emulsified in liquid petrolatum and Arlacel A. Ascites produced without tubercle bacilli or tumor cells may increase the use of rats for antibody production.

Effects of coprophagy on serum urea and the weight of the gastrointestinal tract of fed or fasted rats

Coprophagy can be minimized by fitting rat cages with metal grids which allow faecal pellets to pass through to the floor of the cage. When bedding was omitted overnight, the extent of coprophagy could be estimated from the weight of the droppings on the cage floor or the weight of the gastrointestinal (GI) tract removed from rats housed with or without grids. The effect of coprophagy was also demonstrated by the elevation of serum urea nitrogen in rats that consumed faeces. Therefore, precautions against coprophagy, or their absence, should be specified in all experimental protocols and reports.

Transforming growth factor-beta-mediated apoptosis in the Ramos B-lymphoma cell line is accompanied by caspase activation and Bcl-XL downregulation

Upon transforming growth factor-beta (TGF-beta) treatment, Ramos cells, a B-cell lymphoma cell line, undergo apoptosis, as measured by annexin V labeling, DNA fragmentation, and propidium iodide staining. Apoptosis could be observed by 24 h after TGF-beta exposure and occurred before the development of a significant blockage of cell cycle progression. TGF-beta-mediated apoptosis was also accompanied by a strong induction of caspase-3 subfamily activity. Incubation of cells with the caspase inhibitor Z-VAD.FMK at 20 microM, but not at 10 microM, prevented TGF-beta-induced apoptosis from occurring. By comparison, caspase-3 subfamily activity was 87% inhibited at 10 microM Z-VAD.FMK and completely inhibited at 20 microM. Because of TGF-beta's well-established role of regulating gene transcription, the mRNA levels for proteins associated with apoptosis (Fas- and Fas-associated proteins, Bcl-2 family members, IAP proteins, and I kappa B) were also studied. After 24 h of TGF-beta treatment, the most significant mRNA changes occurred with Bcl-XL (two-fold decrease) and Bik (twofold increase). TGF-beta treatment also resulted after 48 h in a fivefold decrease in Bcl-XL protein levels, based on immunoblotting analysis. Therefore, TGF-beta-mediated apoptosis involves the activation of caspases. In addition, TGF-beta transcriptionally regulates Bcl-2 family members, Bcl-XL and Bik, to further influence the apoptosis process.

Prevention of lithium nephrotoxicity in a novel one-hour model in rats

It is well established that lithium can cause morphologically visible damage to the kidneys of humans and animals. Although the clinical significance of its nephrotoxicity is debatable, it would be desirable to find a method to prevent lithium's effect on the kidneys. Toward this end, we have developed a novel method for producing nephrotoxicity that will be useful for research on prevention. A single, large, toxic dose of lithium chloride (LiCl) caused necrosis of the distal convoluted tubules, which was visible by light microscopy in 30 min, had fully developed in 1 h, and had disappeared by the next day. The lesions were seen after i.p. or i.v. injections of fasted rats of three different strains. Equivalent doses of NaCl, KCl, MgCl2 and combinations thereof had no such effect, nor did they inhibit nephrotoxicity when incorporated into the LiCl solution. However, relatively small doses of LiCl injected by any route 3 or 24 h beforehand prevented the nephrotoxicity. The mechanism of prevention is not known, but it does not involve reduction of lithium levels in the kidneys.

Cloning and characterization of human Jak-2 kinase: high mRNA expression in immune cells and muscle tissue

We report on the cloning and sequence analysis of the mRNA coding for full-length human Janus kinase 2 (Jak2). The human form of Jak2 is 1132 amino acids in length with a M(r) of 131 KDa. It has 95% sequence similarity to pig and rat Jak2. The highest level of mRNA expression was found in the spleen, peripheral blood leukocytes, and testis. Also a significantly high level of Jak2 mRNA was found in heart and skeletal muscle. Northern blot analysis showed three mRNA species in all tissues tested, except heart and skeletal muscle, of 7.6, 5.9, and 4.8 Kb. In skeletal muscle and heart, three mRNA species of 7.6, 4.8, and 3.9 Kb were identified. The catalytic domain of the human Jak2 was expressed and its specificity for phosphorylating peptide substrates derived from the gp130, STAT, and Jak3 molecules was determined and compared to that for human Jak1 and Jak3.

Petechial hemorrhages in the small intestinal Peyer's patches: a new manifestation of systemic anaphylaxis

Systemic anaphylaxis in the rat has major manifestations in the small intestine. In August rats, but not in other strains, intestinal anaphylaxis was accompanied by petechial hemorrhages in Peyer's patches. The occurrence of petechiae was not proportional to the intensity of prostration, cyanosis or gut congestion. No hemorrhages were found in other organs. The petechiae occurred in August rats of either sex after sensitization and challenge with any of several antigens and adjuvants and after passive sensitization with antiserum. The number of Peyer's patches with hemorrhage varied from one to all 20 in individual rats. The occurrence of petechiae was not influenced significantly by the route of sensitization or challenge, by the presence or absence of pinworms in the cecum, or by ancillary treatment at time of challenge with normal serum, normal blood, heparin, pertussis vaccine or lipopolysaccharide. The intestinal mast cells of the susceptible August rats were not different from the mast cells of the resistant strains. Furthermore, mast cells did not reside in the lymphoid follicles of Peyer's patches which was the site of the petechial hemorrhages in anaphylactic August rats. Nor did injections of histamine, serotonin or both cause hemorrhages in Peyer's patches.

hUBC9 associates with MEKK1 and type I TNF-alpha receptor and stimulates NFkappaB activity

hUBC9, an E2 ubiquitin conjugating enzyme, was identified by yeast two-hybrid screening and coprecipitation studies to interact with MEKK1 and the type I TNF-alpha receptor, respectively. Because both of these proteins regulate NFkappaB activity, the role of hUBC9 in modulating NFkappaB activity was investigated. Overexpression of hUBC9 in HeLa cells stimulated the activity of NFkappaB as determined by NFkappaB reporter and IL-6 secretion assays. hUBC9 also synergized with MEKK1 to activate NFkappaB reporter activity. Thus, hUBC9 modulates NFkappaB activity which, at least in part, can be attributed to its interaction with MEKK1 and the type I TNF-alpha receptor.

Distribution of small intestinal lesions in anaphylaxis of rats

Hemorrhage and congestion were not uniformly distributed along the small intestine during systemic anaphylaxis in rats. Duodenum had little hemorrhage and congestion and the terminal ileum had even less. Maximum involvement occurred in jejunum of 13% of rats, in ileum of 47%, and in both jejunum and ileum of 40%. Sequential scoring along the entire length of small intestine revealed different patterns of distribution with more than one peak of intensity in some of the rats. Within a lesioned area, banding was common except where hemorrhage and congestion were so severe as to obliterate all patterns. Banding represented a gradient of injury with respect to the vascular supply. The pale stripes (less severe hemorrhage) contained the penetrating vessels derived from the terminal mesenteric arcades. The dark stripes (more severe hemorrhage) did not contain such vessels. In addition, the mesenteric side of the intestine was less affected than the antimesenteric side. This constituted a second gradient that might also be related to the distance from the vascular supply. In both instances, proximity to larger blood vessels had a protective effect. These two gradients and the variable sites and patterns of distribution have not been described previously in intestinal anaphylaxis. Gradients and the variability of the distribution of lesions in intestinal anaphylaxis should be considered in experiments on pathogenesis and altered function.

Fluorinated anesthetics differ in toxic effects on peritoneum and subjacent tissues

Intraperitoneal injection of fluorinated anesthetics produced anesthesia in rats. This was followed by toxic effects on peritoneal organs and surfaces, except for sevoflurane, which did not produce any lesions.

Influence of body size on lithium levels in rats

Lithium chloride was injected into rats by the intraperitoneal or intravenous route. The dose was proportional to body weight, in the conventional manner. Lithium levels in blood serum and organs were determined after 3-24 h. Within a given strain, large rats had higher levels than small rats. The size of the rats, and not their age, was the determining factor. The large rats had more adipose tissue than the small rats. Inasmuch as lithium distributes in body water, the excess fat in large rats reduces its volume of distribution, which may be responsible for raising the lithium levels in aqueous compartments, including serum. Male and female rats of equal body size developed equal lithium levels in serum.

"Movement" in work status after pain facility treatment

STUDY DESIGN

This was a randomized prospective follow-up study of pain facility treatment of chronic pain patients with low back pain, with return to work and work capacity as the outcome measures.

OBJECTIVES

To determine if after pain facility treatment chronic pain patients "move" in and out of work and in their work capacity; to determine the patterns of "movement;" and to determine the post-pain facility treatment follow-up sampling time points that would maximize the number of chronic pain patients correctly classified according to their final work and work capacity status.

SUMMARY OF BACKGROUND DATA

Past research and empiric observation have indicated that chronic pain patients may "move" after pain facility treatment in and out of work and in their job work capacity. Such "movement" can affect the results of outcome studies.

METHODS

Two hundred thirty-six consecutive chronic pain patients who fit study selection criteria were followed up at 1, 3, 6, 12, 18, 24, and 30 months after pain facility treatment for determination of work and work capacity status and separated according to the pattern of movement. Stepwise discriminant analysis was used to answer the study objectives. "Movement" in and out of work for these chronic pain patients also was compared with the US general population.

RESULTS

Chronic pain patients demonstrated eight work and four work capacity movement patterns. The 24- and 1-month time points predicted final work status correctly for 97.0% and 77.0% of the chronic pain patients, respectively, whereas the most significant predictor for correct work capacity status was the 24-month point. The annual percentage change in employment status for these chronic pain patients was more than in the US general population.

CONCLUSIONS

Because chronic pain patients "move" in and out of employment and for work capacity status after pain facility treatment, future outcome studies using these measures will have to consider carefully the impact of "movement" on their results.

Abdominal cocoon: an animal model for a complication of peritoneal dialysis

OBJECTIVE

The purpose of this work was to develop an animal model of sclerosing encapsulating peritonitis, a complication of continuous ambulatory peritoneal dialysis in which the intestines are conglomerated into an ovoid cocoonlike structure.

DESIGN

Toward this end, rats were injected with a chemical irritant (household bleach) intraperitoneally. One week later, before the resultant peritonitis could cause adhesions, 10 or 25 mL of fresh whole rat blood was injected into the peritoneal cavity. Two weeks later, the effect of the treatments was evaluated by macroscopic and microscopic study.

RESULTS

The irritant caused a chemical peritonitis. The subsequently injected blood clotted on the surfaces of the inflamed intestines, and contraction of the clot (syneresis) was responsible for bringing the intestinal loops together. This conglomeration was made permanent by the fibrosis evoked by the chemical peritonitis. The end result was an ovoid encapsulated mass of intestines and other viscera.

CONCLUSION

An animal model for an abdominal cocoon has been produced. It can be used for studies of the pathogenesis and prevention of this complication of peritoneal dialysis.

Lithium distribution in experimental inflammation of brain and spinal cord

1. Autoimmune inflammation of the nervous system caused extensive changes in the distribution of lithium injected into rats. 2. Serum lithium levels were greatly increased because of failure of renal excretion caused by pre-renal azotemia, urinary retention and lack of dietary sodium. Brain, spinal cord, pituitary and adrenal levels of lithium were also elevated, reflecting the high serum levels. 3. However, the location and degree of this elevation corresponded to the predominant location of the inflammation. As a result, lithium levels in spinal cord approached and even exceeded the lithium content of brain.

Metallic tin-induced lymphadenopathy in rat strains and hybrids

Metallic tin powder, injected into Lewis rats obtained from three different sources, caused enlargement of the regional draining lymph nodes. The histopathology featured epithelioid cell granulomas around phagocytosed particles of tin and an intense hyperplasia of plasma cells. The same material injected into August rats enlarged the lymph nodes but the enlargement was caused by granulomas without a major concomitant plasma cell response. In most other strains, tin produced less lymph node enlargement and the plasma cell response was minimal. However, F1 hybrids of Lewis rats with either the August, Brown-Norway (BN), or Dark Agouti (DA) strains developed plasma cell hyperplasia similar to that seen in the parental Lewis strain. The response to tin was the same whether the tin was injected into the feet or into the peritoneal cavity. Thus, the lymph node response to metallic tin varied from a slight, banal response to insoluble foreign particles, to an exuberant granulomatous hyperplasia, to an intense plasmacellular hyperplasia, depending on the genetic characteristics of the subjects.

Quality of life assessment in gynaecological cancer patients

The feasibility of quality of life (QOL) assessment in a heterogeneous group of gynaecological cancer patients undergoing chemotherapy was determined. All new patients being prescribed cytotoxic chemotherapy were asked to complete a modified QOL assessment tool. The elected assessment tool is the Functional Assessment Cancer Therapy-General (FACT-G) tool, comprising 33 questions under 5 broad categories: physical well-being, social well-being, relationship with doctor, emotional well-being and functional well-being. Raw scores were calculated and then transformed to a 0-100 scale. Twenty eight patients received a total of 75 treatment cycles of chemotherapy. Four patients were not offered the assessment due to language difficulties. All patients offered the test satisfactorily completed the test to allow statistical analysis. The average number of chemotherapy courses received was 2.5 (range: 1-6). Of a total possible 2,475 study items (33 items x 75 cycles), 240 items were not answered (10%). Of these 240 unanswered items, 2 items (#14 and #15) comprised 38%. The mean transformed score for physical well-being was 32 (SE 2.5), for social well-being the mean transformed score was 50 (SE 1.7), relationship with doctor 86 (SE 2.4), emotional well-being 41 (SE 2) and functional well-being was 54 (SE 2.6). The assessment of QOL indices in gynaecological cancer patients undergoing chemotherapy is feasible. Further research needs to determine the optimal QOL tool for this patient population.

Gene expression of the androgen repressed rat TR2 orphan receptor: a member of steroid receptor superfamily

A full-length rat cDNA clone was obtained from the TR2 orphan receptor, a member of the steroid receptor superfamily, using cDNA library screening and 3' RACE-PCR technology. Under these conditions, only the TR2-11 form of the TR2 orphan receptor, the major form found in prostate, was identified. The overall amino acid homology between human and rat TR2-11 orphan receptors was near 90% with one amino acid difference in the DNA-binding domain sequence. Northern blot analysis identified multiple forms of the TR2 orphan receptor mRNAs expressed in human and rat prostates. Androgens repressed TR2 orphan receptor mRNA levels in human prostate LNCaP cells and rat ventral prostate. Polyclonal anti-TR2 orphan receptor antibodies raised from a unique TR2 orphan receptor 20 amino acid peptide were used to localize the TR2 orphan receptor in the nuclei of prostate and epididymis epithelium cells. Together, these data demonstrate that the TR2 orphan receptor can be expressed at mRNA and protein levels in the human and rat prostrates and may have some potential function in mediating androgen action in these tissues.

Androgen receptor: an overview

The action of androgens in regulating development and growth is mediated by androgen receptor (AR). AR is a member of the steroid hormone receptor superfamily, a class of receptors that function through their ability to regulate the transcription of specific genes. The AR is located in various target tissues, with its levels and activity altered with the onset of various cellular events (e.g., sexual development, malignant transformation). The modulation of AR levels occurs through a number of mechanisms, including transcription, and is regulated by various factors (e.g., androgens). The ability of AR to modulate gene transcription is through its interaction with specific DNA sequences located near or within the target gene promoter. The importance of the AR in reproductive physiology has been emphasized by the finding of AR mutations, leading to a variety of disorders, including testicular feminization syndrome. In this article, we review the structure and function of AR and the role AR plays in the function of the mammalian system.

Signal transduction differences between 5-hydroxytryptamine type 2A and type 2C receptor systems

The cDNAs for human 5-hydroxytryptamine (5-HT)2C and 5-HT2A receptors were stably transfected separately into parent Chinese hamster ovary cells, and cell lines in which levels of transfected receptor protein expression and accumulation of inositol phosphates in response to 5-HT were comparable were chosen for study. The effect of activation of these receptors on 5-HT1B-like receptor-mediated responsiveness (i.e., inhibition of forskolin-stimulated cAMP accumulation) was studied. Activation of 5-HT2C receptors with 5-HT (0.1-100 microM) abolished the 5-HT1B-like response, which returned when 5-HT2C receptors were blocked with mesulergine (1 microM). Furthermore, the maximal response to 5-carboxytryptamine was reduced in a concentration-dependent manner by the 5-HT2A/5-HT2C-selective partial agonist (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane. In contrast, activation of 5-HT2A receptors with either 5-HT or (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane did not alter the 5-HT1B-like response. The reduction of 5-HT1B-like responsiveness produced by 5-HT2C receptor activation was independent of protein kinase C activation and increases in the intracellular calcium concentration. Although 5-HT2A and 5-HT2C receptors are strikingly similar in structure and pharmacology, and the signal transduction systems coupled to these receptors have been thought to be similar, if not identical, these data provide the first evidence for fundamental differences in the signal transduction systems of these 5-HT2 receptor subtypes.

The balance between lymphatic and systemic absorption determines the outcome of sensitization for anaphylaxis in rats

Rats were sensitized to chicken ovalbumin or human gamma-globulin by inoculation without adjuvants into the peritoneal cavity in the healing phase of a chemical peritonitis. This phase is associated with striking enhancement of lymphatic absorption. Small doses of antigen sensitized the rats for subsequent induction of anaphylaxis, but large doses were almost completely ineffective (inverse dose-response relation). When certain adjuvants were added to the antigen, both high and low doses of antigen were effective sensitizers for anaphylaxis. Neither high nor low doses of antigen sensitized if injected without adjuvants into the unprepared peritoneal cavity or by any other route. The effects of sensitization with low or high doses of antigen and the results of inoculation by effective and ineffective routes were interpreted in terms of the balance between absorption into the lymphatics and into the systemic blood circulation. Supplemental antigen inoculated into the systemic circulation was able to tip the balance against sensitization even when sensitization was done with potent adjuvants and by a favorable route. Splenectomy had little or no effect on suppression by supplemental antigen.

Method for systemic anaphylactic challenge in the rat using subplantar route

Intravenous injection of antigen is the fastest and most effective way of eliciting anaphylactic shock in previously sensitized rats. When intravenous injection is difficult or undesirable, subplantar challenge is a preferable alternative to the intraperitoneal route.

Neogenesis of skeletal muscle in the postinflammatory rat peritoneum

During the healing phase of a chemical peritonitis, one or several skeletal muscle fibers develop, de novo, in the peritoneum of the adult of weanling rat diaphragm. One week after the initial injury the new muscle fibers are narrow and have central nuclei and cross-striations. The fibers increase progressively in caliber and the nuclei take up a subsarcolemmal location. The newly formed muscle fibers are separated from the intrinsic diaphragmatic muscle by an elastic membrane and by a hand of hyaline connective tissue. They are separated from the peritoneal surface by a zone of granulation tissue. Most new fibers are oriented at right angles to the intrinsic diaphragmatic muscle fibers. Their location and orientation suggest an origin from mesothelium or from fibroblasts in the granulation tissue rather than from the intrinsic diaphragmatic muscle. A similar phenomenon can be induced in the pleura on the other side of the diaphragm. In contrast, damage to the diaphragmatic muscle by injection of aluminum lactate does not engender myogenesis in the location described despite active regeneration in the intrinsic muscle.