Klotho is highly expressed in the chief sites of regulated potassium secretion, and it is stimulated by potassium intake

Klotho regulates many pathways in the aging process, but it remains unclear how it is physiologically regulated. Because Klotho is synthesized, cleaved, and released from the kidney; activates the chief urinary K+ secretion channel (ROMK) and stimulates urinary K+ secretion, we explored if Klotho protein is regulated by dietary K+ and the potassium-regulatory hormone, Aldosterone. Klotho protein along the nephron was evaluated in humans and in wild-type (WT) mice; and in mice lacking components of Aldosterone signaling, including the Aldosterone-Synthase KO (AS-KO) and the Mineralocorticoid-Receptor KO (MR-KO) mice. We found the specific cells of the distal nephron in humans and mice that are chief sites of regulated K+ secretion have the highest Klotho protein expression along the nephron. WT mice fed K+-rich diets increased Klotho expression in these cells. AS-KO mice exhibit normal Klotho under basal conditions but could not upregulate Klotho in response to high-K+ intake in the K+-secreting cells. Similarly, MR-KO mice exhibit decreased Klotho protein expression. Together, i) Klotho is highly expressed in the key sites of regulated K+ secretion in humans and mice, ii) In mice, K+-rich diets increase Klotho expression specifically in the potassium secretory cells of the distal nephron, iii) Aldosterone signaling is required for Klotho response to high K+ intake.

Enriched Single-Nucleus RNA-Sequencing Reveals Unique Attributes of Distal Convoluted Tubule Cells

SIGNIFICANCE STATEMENT

High-resolution single-nucleus RNA-sequencing data indicate a clear separation between primary sites of calcium and magnesium handling within distal convoluted tubule (DCT). Both DCT1 and DCT2 express Slc12a3, but these subsegments serve distinctive functions, with more abundant magnesium-handling genes along DCT1 and more calcium-handling genes along DCT2. The data also provide insight into the plasticity of the distal nephron-collecting duct junction, formed from cells of separate embryonic origins. By focusing/changing gradients of gene expression, the DCT can morph into different physiological cell states on demand.

BACKGROUND

The distal convoluted tubule (DCT) comprises two subsegments, DCT1 and DCT2, with different functional and molecular characteristics. The functional and molecular distinction between these segments, however, has been controversial.

METHODS

To understand the heterogeneity within the DCT population with better clarity, we enriched for DCT nuclei by using a mouse line combining "Isolation of Nuclei Tagged in specific Cell Types" and sodium chloride cotransporter-driven inducible Cre recombinase. We sorted the fluorescently labeled DCT nuclei using Fluorescence-Activated Nucleus Sorting and performed single-nucleus transcriptomics.

RESULTS

Among 25,183 DCT cells, 75% were from DCT1 and 25% were from DCT2. In addition, there was a small population (<1%) enriched in proliferation-related genes, such as Top2a , Cenpp , and Mki67 . Although both DCT1 and DCT2 expressed sodium chloride cotransporter, magnesium transport genes were predominantly expressed along DCT1, whereas calcium, electrogenic sodium, and potassium transport genes were more abundant along DCT2. The transition between these two segments was gradual, with a transitional zone in which DCT1 and DCT2 cells were interspersed. The expression of the homeobox genes by DCT cells suggests that they develop along different trajectories.

CONCLUSIONS

Transcriptomic analysis of an enriched rare cell population using a genetically targeted approach clarifies the function and classification of distal cells. The DCT segment is short, can be separated into two subsegments that serve distinct functions, and is speculated to derive from different origins during development.

Poly(ADP-ribose) polymerase-1 affects vasopressin-mediated AQP2 expression in collecting duct cells of the kidney

Poly(ADP-ribosyl)ation (PARylation), as a posttranslational modification mediated by poly(ADP-ribose) polymerases (PARPs) catalyzing the transfer of ADP-ribose from NAD+ molecules to acceptor proteins, involves a number of cellular processes. As mice lacking the PARP-1 gene (Parp1) produce more urine, we investigated the role of PARP-1, the most prevalent member of the PARP family, in the vasopressin-responsive expression of aquaporin-2 (AQP2). In biotin-conjugated nicotinamide adenine dinucleotide (biotin-NAD+) pulldown and immunoprecipitation assays of poly(ADP)-ribose in mpkCCDc14 cells, immunoblots demonstrated that 1-deamino-8-D-arginine vasopressin (dDAVP) induced the PARylation of total proteins, associated with an increase in the cleavage of PARP-1 and cleaved caspase-3 expression. By inhibiting PARP-1 with siRNA, the abundance of dDAVP-induced AQP2 mRNA and protein was significantly diminished. In contrast, despite a substantial decrease in PARylation, the PARP-1 inhibitor (PJ34) had no effect on the dDAVP-induced regulation of AQP2 expression. The findings suggest that PARP-1 protein expression itself, and not PARP-1-mediated PARylation, is necessary for dDAVP-regulated AQP2 expression. Bioinformatic analysis revealed that 408 proteins interact with PARP-1 in the collecting duct (CD) cells of the kidney. Among them, the signaling pathway of the vasopressin V2 receptor was identified for 49 proteins. In particular, β-catenin, which is phosphorylated at Ser552 by dDAVP, was identified as the PARP-1-interacting protein. A significant decrease of β-catenin phosphorylation (Ser552) in response to dDAVP was associated with siRNA-mediated PARP-1 knockdown. Taken together, PARP-1 is likely to play a role in vasopressin-induced AQP2 expression by interacting with β-catenin in renal CD cells.NEW & NOTEWORTHY The poly(ADP-ribose) polymerase (PARP) family catalyzes poly(ADP-ribosylation) (PARylation), which is one of the posttranslational modifications of largely undetermined physiological significance. This study investigated the role of PARP-1, the most prevalent member of the PARP family, in the vasopressin-responsive expression of aquaporin-2 (AQP2). The results demonstrated that PARP-1 protein expression itself, and not PARP-1-mediated PARylation, is necessary for dDAVP-regulated AQP2 expression. β-Catenin, which is phosphorylated at Ser552 by dDAVP, was identified as the PARP-1-interacting protein.

Single cell and spatial transcriptomics analysis of kidney double negative T lymphocytes in normal and ischemic mouse kidneys

T cells are important in the pathogenesis of acute kidney injury (AKI), and TCR+CD4-CD8- (double negative-DN) are T cells that have regulatory properties. However, there is limited information on DN T cells compared to traditional CD4+ and CD8+ cells. To elucidate the molecular signature and spatial dynamics of DN T cells during AKI, we performed single-cell RNA sequencing (scRNA-seq) on sorted murine DN, CD4+, and CD8+ cells combined with spatial transcriptomic profiling of normal and post AKI mouse kidneys. scRNA-seq revealed distinct transcriptional profiles for DN, CD4+, and CD8+ T cells of mouse kidneys with enrichment of Kcnq5, Klrb1c, Fcer1g, and Klre1 expression in DN T cells compared to CD4+ and CD8+ T cells in normal kidney tissue. We validated the expression of these four genes in mouse kidney DN, CD4+ and CD8+ T cells using RT-PCR and Kcnq5, Klrb1, and Fcer1g genes with the NIH human kidney precision medicine project (KPMP). Spatial transcriptomics in normal and ischemic mouse kidney tissue showed a localized cluster of T cells in the outer medulla expressing DN T cell genes including Fcer1g. These results provide a template for future studies in DN T as well as CD4+ and CD8+ cells in normal and diseased kidneys.

Polycystin-2-dependent transcriptome reveals early response of autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations in polycystin genes, Pkd1 and Pkd2, but the underlying pathogenic mechanisms are poorly understood. To identify genes and pathways that operate downstream of polycystin-2 (PC2), a comprehensive gene expression database was created, cataloging changes in the transcriptome immediately following PC2 protein depletion. To explore cyst initiation processes, an immortalized mouse inner medullary collecting duct line was developed with the ability to knock out the Pkd2 gene conditionally. Genome-wide transcriptome profiling was performed using RNA sequencing in the cells immediately after PC2 was depleted and compared with isogenic control cells. Differentially expressed genes were identified, and a bioinformatic analysis pipeline was implemented. Altered expression of candidate cystogenic genes was validated in Pkd2 knockout mice. The expression of nearly 900 genes changed upon PC2 depletion. Differentially expressed genes were enriched for genes encoding components of the primary cilia, the canonical Wnt pathway, and MAPK signaling. Among the PC2-dependent ciliary genes, the transcription factor Glis3 was significantly downregulated. MAPK signaling formed a key node at the epicenter of PC2-dependent signaling networks. Activation of Wnt and MAPK signaling, concomitant with the downregulation of Glis3, was corroborated in Pkd2 knockout mice. The data identify a PC2 cilia-to-nucleus signaling axis and dysregulation of the Gli-similar subfamily of transcription factors as a potential initiator of cyst formation in ADPKD. The catalog of PC2-regulated genes should provide a valuable resource for future ADPKD research and new opportunities for drug development.NEW & NOTEWORTHY Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disease. Mutations in polycystin genes cause the disease, but the underlying mechanisms of cystogenesis are unknown. To help fill this knowledge gap, we created an inducible cell model of ADPKD and assembled a catalog of genes that respond in immediate proximity to polycystin-2 depletion using transcriptomic profiling. The catalog unveils a ciliary signaling-to-nucleus axis proximal to polycystin-2 dysfunction, highlighting Glis, Wnt, and MAPK signaling.

Signaling mechanisms in renal compensatory hypertrophy revealed by multi-omics

Loss of a kidney results in compensatory growth of the remaining kidney, a phenomenon of considerable clinical importance. However, the mechanisms involved are largely unknown. Here, we use a multi-omic approach in a unilateral nephrectomy model in male mice to identify signaling processes associated with renal compensatory hypertrophy, demonstrating that the lipid-activated transcription factor peroxisome proliferator-activated receptor alpha (PPARα) is an important determinant of proximal tubule cell size and is a likely mediator of compensatory proximal tubule hypertrophy.

Circadian gene expression in mouse renal proximal tubule

Circadian variability in kidney function is well recognized but is often ignored as a potential confounding variable in physiological experiments. Here, we have created a data resource consisting of expression levels for mRNA transcripts in microdissected proximal tubule segments from mice as a function of the time of day. Small-sample RNA sequencing was applied to microdissected S1 proximal convoluted tubules and S2 proximal straight tubules. After stringent filtering, the data were analyzed using JTK-Cycle to detect periodicity. The data set is provided as a user-friendly webpage at https://esbl.nhlbi.nih.gov/Databases/Circadian-Prox2/. In proximal convoluted tubules, 234 transcripts varied in a circadian manner (4.0% of the total). In proximal straight tubules, 334 transcripts varied in a circadian manner (5.3%). Transcripts previously known to be associated with corticosteroid action and with increased flow were found to be overrepresented among circadian transcripts peaking during the "dark" portion of the day [zeitgeber time (ZT)14-22], corresponding to peak levels of corticosterone and glomerular filtration rate in mice. To ask whether there is a time-of-day dependence of protein abundances in the kidney, we carried out LC-MS/MS-based proteomics in whole mouse kidneys at ZT12 and ZT0. The full data set (n = 6,546 proteins) is available at https://esbl.nhlbi.nih.gov/Databases/Circadian-Proteome/. Overall, 293 proteins were differentially expressed between ZT12 and ZT0 (197 proteins greater at ZT12 and 96 proteins greater at ZT0). Among the regulated proteins, only nine proteins were found to be periodic in the RNA-sequencing analysis, suggesting a high level of posttranscriptional regulation of protein abundances.NEW & NOTEWORTHY Circadian variation in gene expression can be an important determinant in the regulation of kidney function. The authors used RNA-sequencing transcriptomics and LC-MS/MS-based proteomics to identify gene products expressed in a periodic manner. The data were used to construct user-friendly web resources.

Abstract 071: Hypertension Rewrites The Kidney Transcriptome And Drives Nephropathy

Hypertensive nephropathy is a commonly diagnosed form of chronic kidney disease (CKD), but the biological processes underlying disease initiation are poorly understood. Here, we explore if non-malignant hypertension (HTN) is sufficient to initiate kidney damage and seek to identify pathways that drive disease development. We created a genetically defined hypertensive mouse by introducing activating mutations in the Ste20p-related proline alanine-rich kinase (SPAK) that are solely expressed in distal convoluted tubule cells. These constitutively active SPAK mice (CA-SPAK) develop salt-sensitive HTN due to hyperactivation of the thiazide-sensitive sodium chloride cotransporter (NCC). For these studies, CA-SPAK and control mice were fed either control salt (0.74% NaCl, CSD) or high salt diets (2% NaCl, HSD) for 24 weeks, and renal function and blood pressure were evaluated. RNASeq was performed to assess changes in the kidney transcriptional profile, the results of which were used for pathway enrichment analysis. CA-SPAK mice fed CSD develop HTN and show declining renal function starting at 26 weeks old and progresses over the next 10 weeks until they develop azotemia (BUN 30.8 vs 21.5 mg/dl; PCr - 0.42 vs 0.25 mg/dl, n=8) and albuminuria (5.2 vs 1.8 mg/day; n=8). HSD exacerbates HTN in CA-SPAK and initiates the same decline of renal function after only 8 weeks (20 weeks old). To identify changes in renal gene expression associated with the onset of function decline, we performed RNASeq on cortical tissue from both genotypes fed HSD for 8 weeks. We identified 3568 deferentially expressed genes in CA-SPAK. Pathway enrichment analysis found 3 biological processes associated with the early decline in CA-SPAK renal function that includes alterations of the filtration barrier (e.g. decreased nephrin, podocalyxin, synaptopodin, CD2AP, collagen 4a3, laminin B2), albuminuria associated genes (e.g. decreased cubilin, megalin, mucin 1), and immune system activation (e.g. increased MHC class II, T and B lymphocytes markers). Our findings from CA-SPAK mice demonstrate that non-malignant HTN can induce altered renal gene expression, the consequence of which is sufficient to disrupt kidney function resulting in the onset of hypertensive nephropathy.

Systems Biology of the Vasopressin V2 Receptor: New Tools for Discovery of Molecular Actions of a GPCR

Systems biology can be defined as the study of a biological process in which all of the relevant components are investigated together in parallel to discover the mechanism. Although the approach is not new, it has come to the forefront as a result of genome sequencing projects completed in the first few years of the current century. It has elements of large-scale data acquisition (chiefly next-generation sequencing-based methods and protein mass spectrometry) and large-scale data analysis (big data integration and Bayesian modeling). Here we discuss these methodologies and show how they can be applied to understand the downstream effects of GPCR signaling, specifically looking at how the neurohypophyseal peptide hormone vasopressin, working through the V2 receptor and PKA activation, regulates the water channel aquaporin-2. The emerging picture provides a detailedframework for understanding the molecular mechanisms involved in water balance disorders, pointing the way to improved treatment of both polyuric disorders and water-retention disorders causing dilutional hyponatremia.

Diesel Exhaust Particles Impair Therapeutic Effect of Human Wharton's Jelly-Derived Mesenchymal Stem Cells against Experimental Colitis through ROS/ERK/cFos Signaling Pathway

Background and Objectives

Epidemiological investigations have shown positive correlations between increased diesel exhaust particles (DEP) in ambient air and adverse health outcomes. DEP are the major constituent of particulate atmospheric pollution and have been shown to induce proinflammatory responses both in the lung and systemically. Here, we report the effects of DEP exposure on the properties of human Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs), including stemness, regeneration, and immunomodulation.

Methods and Results

Non-apoptotic concentrations of DEP (10 μg/ml) inhibited the migration and osteogenic differentiation capacity of WJ-MSCs. Gene expression profiling showed that DEP increased intracellular reactive oxygen species (ROS) and expression of pro-inflammatory and metabolic-process-related genes including cFos. Furthermore, WJ-MSCs cultured with DEP showed impaired suppression of T cell proliferation that was reversed by inhibition of ROS or knockdown of cFos. ERK inhibition assay revealed that DEP-induced ROS regulated cFos through activation of ERK but not NF-κB signaling. Overall, low concentrations of DEP (10 μg/ml) significantly suppressed the stemness and immunomodulatory properties of WJ-MSCs through ROS/ERK/cFos signaling pathways. Furthermore, WJ-MSCs cultured with DEP impaired the therapeutic effect of WJ-MSCs in experimental colitis mice, but was partly reversed by inhibition of ROS.

Conclusions

Taken together, these results indicate that exposure to DEP enhances the expression of pro-inflammatory cytokines and immune responses through a mechanism involving the ROS/ERK/cFos pathway in WJ-MSCs, and that DEP-induced ROS damage impairs the therapeutic effect of WJ-MSCs in colitis. Our results suggest that modulation of ROS/ERK/cFos signaling pathways in WJ-MSCs might be a novel therapeutic strategy for DEP-induced diseases.

Doxycycline Changes the Transcriptome Profile of mIMCD3 Renal Epithelial Cells

Tetracycline-inducible gene expression systems have been used successfully to study gene function in vivo and in vitro renal epithelial models but the effects of the common inducing agent, doxycycline (DOX), on gene expression are not well appreciated. Here, we evaluated the DOX effects on the transcriptome of a widely used renal epithelial cell model, mIMCD3 cells, to establish a reference. Cells were grown on permeable filter supports in the absence and presence of DOX (3 or 6 days), and genome-wide transcriptome profiles were assessed using RNA-Seq. We found DOX significantly altered the transcriptome profile, changing the abundance of 1,549 transcripts at 3 days and 2,643 transcripts at 6 days. Within 3 days of treatment, DOX significantly decreased the expression of multiple signaling pathways (ERK, cAMP, and Notch) that are associated with cell proliferation and differentiation. Genes associated with cell cycle progression were subsequently downregulated in cells treated with DOX for 6 days, as were genes involved in cellular immune response processes and several cytokines and chemokines, correlating with a remarkable repression of genes encoding cell proliferation markers. The results provide new insight into responses of renal epithelial cells to DOX and a establish a resource for DOX-mediated gene expression systems.

Association between air pollution and chronic rhinosinusitis: a nested case-control study using meteorological data and national health screening cohort data

BACKGROUND

Inconsistent results about the effect of air pollution on chronic rhinosinusitis (CRS) have been reported. This study aimed to evaluate the impact of meteorological conditions/air pollution on the prevalence of CRS in adult Koreans.

METHODOLOGY

The data from the Korean National Health Insurance Service-Health Screening Cohort from 2002 through 2015 were used. A CRS group (defined as ICD-10 codes J32, n=6159) was matched with a control group (n=24,636) in 1:4 ratios by age, sex, income, and region of residence. The meteorological conditions and air pollution data included the daily mean, highest, and lowest temperature (°C), daily temperature range (°C), relative humidity (%), ambient atmospheric pressure (hPa), sunshine duration (hr), and the rainfall (mm), SO2 (ppm), NO2 (ppm), O3 (ppm), CO (ppm), and PM10 (μg/m3) levels before the CRS diagnosis. Crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for CRS were analyzed using logistic regression analyses.

RESULTS

When the NO2 level increased by 0.1 ppm, the odds for CRS increased 5.40 times, and when the CO level increased by 1 ppm and PM10 increased by 10 μg/m3, the odds for CRS decreased 0.75 times and 0.93 times, respectively. Other meteorological conditions, such as the mean/highest/lowest temperature, temperature range, rainfall and other air pollution, such as SO2 and O3, were not statistically significant. NO2 for 90 days before the index date increased the risk of CRS in all subgroups, except for the nasal polyp and older age subgroups.

CONCLUSION

CRS is related to high concentrations of NO2.

Bayesian identification of candidate transcription factors for the regulation of Aqp2 gene expression

Aquaporin-2 (Aqp2) gene transcription is strongly regulated by vasopressin in the renal collecting duct. However, the transcription factors (TFs) responsible for the regulation of expression of Aqp2 remain largely unknown. We used Bayes' theorem to integrate several -omics data sets to stratify the 1,344 TFs present in the mouse genome with regard to probabilities of regulating Aqp2 gene transcription. Also, we carried out new RNA sequencing experiments mapping the time course of vasopressin-induced changes in the transcriptome of mpkCCD cells to identify TFs that change in tandem with Aqp2. The analysis identified 17 of 1,344 TFs that are most likely to be involved in the regulation of Aqp2 gene transcription. These TFs included eight that have been proposed in prior studies to play a role in Aqp2 regulation, viz., Cebpb, Elf1, Elf3, Ets1, Jun, Junb, Nfkb1, and Sp1. The remaining nine represent new candidates for future studies (Atf1, Irf3, Klf5, Klf6, Mef2d, Nfyb, Nr2f6, Stat3, and Nr4a1). Conspicuously absent is CREB (Creb1), which has been widely proposed to mediate vasopressin-induced regulation of Aqp2 gene transcription (Nielsen S, Frokiaer J, Marples D, Kwon TH, Agre P, Knepper MA. Physiol Rev 82: 205-244, 2002; Kortenoeven ML, Fenton RA. Biochim Biophys Acta 1840: 1533-1549, 2014; Bockenhauer D, Bichet DG. Nat Rev Nephrol 11: 576-588, 2015; Pearce D, Soundararajan R, Trimpert C, Kashlan OB, Deen PM, Kohan DE. Clin J Am Soc Nephrol 10: 135-146, 2015). Instead, another CREB-like TF, Atf1, ranked fourth among all TFs. RNA sequencing time-course experiments showed a rapid increase in Aqp2 mRNA, within 3 h of vasopressin exposure. This response was matched by an equally rapid increase in the abundance of the mRNA coding for Cebpb, which we have shown by chromatin immunoprecipitation-sequencing studies to bind downstream from the Aqp2 gene. The identified TFs provide a roadmap for future studies to understand regulation of Aqp2 gene expression.NEW & NOTEWORTHY Abetted by the advent of systems biology-based ("-omics") techniques in the 21st century, there has been a massive expansion of published data relevant to virtually every physiological question. The authors have developed a large-scale data integration approach based on the application of Bayes'' theorem. In the current work, they integrated 12 different -omics data sets to identify the transcription factors most likely to mediate vasopressin-dependent regulation of transcription of the aquaporin-2 gene.

Mask-induced dermatoses during the COVID-19 pandemic: a questionnaire-based study in 12 Korean hospitals

BACKGROUND

During the coronavirus disease 2019 (COVID-19) pandemic, various adverse skin reactions to long-term mask wearing have been reported.

AIM

To assess the clinical features of mask-induced dermatoses and to recommend prevention and treatment options.

METHODS

From April to August 2020, questionnaires including topics such as demographic information, pre-existing skin disorders, reported mask-related symptoms, daily mask-wearing duration and frequency, types of masks used and whether the participant was a healthcare worker, were distributed to patients in 12 hospitals. Dermatologists assessed skin lesions, confirmed diagnosis and recorded treatments.

RESULTS

Itchiness was the most frequent symptom, mostly affecting the cheeks. The most common skin disease was new-onset contact dermatitis (33.94%), followed by new-onset acne (16.97%) and worsening of pre-existing acne (16.97%). Daily wearing of masks was significantly (P = 0.02) associated with new-onset contact dermatitis. More than half of patients with pre-existing skin problems experienced disease worsening while wearing masks. Longer duration of wearing (> 6 h/day, P = 0.04) and use of cotton masks (P < 0.001) significantly increased acne flare-up. Healthcare workers had a higher incidence of skin disease. Skin lesions were generally mild and well tolerated with topical treatment. The study had some limitations: the effect of seasonal characteristics and other risk factors were not assessed, and the patients were visiting dermatological clinics and had interest in their skin status, thus, there may have been selection bias.

CONCLUSION

Mask-induced/-triggered dermatoses contribute to increase the dermatological burden during the pandemic.

NGS-Integrator: An efficient tool for combining multiple NGS data tracks using minimum Bayes' factors

BACKGROUND

Next-generation sequencing (NGS) is widely used for genome-wide identification and quantification of DNA elements involved in the regulation of gene transcription. Studies that generate multiple high-throughput NGS datasets require data integration methods for two general tasks: 1) generation of genome-wide data tracks representing an aggregate of multiple replicates of the same experiment; and 2) combination of tracks from different experimental types that provide complementary information regarding the location of genomic features such as enhancers.

RESULTS

NGS-Integrator is a Java-based command line application, facilitating efficient integration of multiple genome-wide NGS datasets. NGS-Integrator first transforms all input data tracks using the complement of the minimum Bayes' factor so that all values are expressed in the range [0,1] representing the probability of a true signal given the background noise. Then, NGS-Integrator calculates the joint probability for every genomic position to create an integrated track. We provide examples using real NGS data generated in our laboratory and from the mouse ENCODE database.

CONCLUSIONS

Our results show that NGS-Integrator is both time- and memory-efficient. Our examples show that NGS-Integrator can integrate information to facilitate downstream analyses that identify functional regulatory domains along the genome.

An integrative proteogenomics approach reveals peptides encoded by annotated lincRNA in the mouse kidney inner medulla

Long noncoding RNAs (lncRNAs) are intracellular transcripts longer than 200 nucleotides and lack protein-coding information. A subclass of lncRNA known as long intergenic noncoding RNAs (lincRNAs) are transcribed from genomic regions that share no overlap with annotated protein-coding genes. Increasing evidence has shown that some annotated lincRNA transcripts do in fact contain open reading frames (ORFs) encoding functional short peptides in the cell. Few robust methods for lincRNA-encoded peptide identification have been reported, and the tissue-specific expression of these peptides has been largely unexplored. Here we propose an integrative workflow for lincRNA-encoded peptide discovery and test it on the mouse kidney inner medulla (IM). In brief, low molecular weight protein fractions were enriched from homogenate of IMs and trypsinized into shorter peptides, which were sequenced by high resolution liquid chromatography-tandem mass spectrometry (LC-MS/MS). To curate a hypothetical lincRNA-encoded peptide database for peptide-spectrum matching following LC-MS/MS, we performed RNA-Seq on IMs, computationally removed reads overlapping with annotated protein-coding genes, and remapped the remaining reads to a database of mouse noncoding transcripts to infer lincRNA expression. Expressed lincRNAs were searched for ORFs by an existing rule-based algorithm, and translated ORFs were used for peptide-spectrum matching. Peptides identified by LC-MS/MS were further evaluated by using several quality control criteria and bioinformatics methods. We discovered three novel lincRNA-encoded peptides, which are conserved in mouse, rat, and human. The workflow can be adapted for discovery of small protein-coding genes in any species or tissue where noncoding transcriptome information is available.

Fluid-electrolyte homeostasis requires histone deacetylase function

Histone deacetylase (HDAC) enzymes regulate transcription through epigenetic modification of chromatin structure, but their specific functions in the kidney remain elusive. We discovered that the human kidney expresses class I HDACs. Kidney medulla-specific inhibition of class I HDACs in the rat during high-salt feeding results in hypertension, polyuria, hypokalemia, and nitric oxide deficiency. Three new inducible murine models were used to determine that HDAC1 and HDAC2 in the kidney epithelium are necessary for maintaining epithelial integrity and maintaining fluid-electrolyte balance during increased dietary sodium intake. Moreover, single-nucleus RNA-sequencing determined that epithelial HDAC1 and HDAC2 are necessary for expression of many sodium or water transporters and channels. In performing a systematic review and meta-analysis of serious adverse events associated with clinical HDAC inhibitor use, we found that HDAC inhibitors increased the odds ratio of experiencing fluid-electrolyte disorders, such as hypokalemia. This study provides insight on the mechanisms of potential serious adverse events with HDAC inhibitors, which may be fatal to critically ill patients. In conclusion, kidney tubular HDACs provide a link between the environment, such as consumption of high-salt diets, and regulation of homeostatic mechanisms to remain in fluid-electrolyte balance.

P0013MAP KINASES-REGULATED PROTEINS IN SIGNALING PATHWAYS OF VASOPRESSIN IN KIDNEY COLLECTING DUCT

Background and Aims

Activation of G protein-coupled vasopressin V2 receptor (V2R) is critical in water and electrolyte transport in the kidney collecting duct (CD) cells. Stimulation of V2R affects several downstream pathways, including PKA, PI3K/AKT, Wnt, and Ca2+/calmodulin. Previous studies have shown that MAP kinases are also involved as an apparent downstream signaling pathway of V2R. However, the role of MAP kinases and their substrate proteins in the vasopressin signaling, including the regulation of AQP2 expression and phosphorylation, are unclear. In the present study, substrates of MAP kinases were identified using bioinformatic analyses, and they were mapped on the downstream signaling pathways of V2R. Tripartite motif-containing protein 28 (TRIM28) was identified as a substrate of ERK1 as well as a vasopressin-responsive protein via bioinformatic tools. We further evaluated whether TRIM28 plays a role in vasopressin-mediated regulation of AQP2 in the kidney CD.

Method

To identify comprehensive substrates of MAP kinases in the kidney CD, we investigated 1) the expression of MAP kinases in CD cells by use of databases based on high-throughput profiles of transcriptome and proteome (http://hpcwebapps.cit.nih.gov/ESBL/Database/index.html); and 2) MAP kinases substrates expressed in the CD cells by use of protein phosphorylation databases (PhosphoNetworks and RegPhos 2.0). The identified substrates were mapped on the downstream signaling of V2R. Cellular and subcellular localization of selected substrate protein (TRIM28) was examined by immunohistochemistry. The role of TRIM28 in vasopressin-mediated AQP2 regulation was examined by quantitative real-time PCR (qRT-PCR) and semiquantitative immunoblotting after RNA interference of TRIM28 in mpkCCDc11 cells.

Results

Immunoblotting of mpkCCDc11 cells revealed that both p-ERK1/2 and pS261-AQP2 expression was decreased in response to dDAVP (10-9 M) stimulation. In silico analyses demonstrated that five MAP kinases (ERK1, ERK2, ERK3, JNK2, and MAPK p38 alpha) were identified as the MAP kinases expressed in kidney CD cells. Based on several protein kinase-substrates databases, 189 proteins were identified as the substrates of the five MAP kinases. In particular, sequential data mining revealed TRIM28, as the substrate of ERK1, has the only one phosphorylation site which was down-regulated by vasopressin stimulation. Since TRIM28 is a transcription cofactor and also a ubiquitin-protein E3 ligase, we examined whether TRIM28 is involved in the regulation of AQP2 expression as a mediator of MAP kinases action. Immunofluorescence labeling of mouse and rat kidneys revealed that TRIM28 was exclusively expressed in the nuclei of the tubular epithelial cells, including CD cells. dDAVP-induced AQP2 mRNA and protein up-regulation was significantly attenuated in mpkCCDc11 cells with siRNA-mediated knockdown of TRIM28.

Conclusion

We identify MAP kinase substrates in the kidney CD, which are mapped on the downstream signaling pathways of V2R. TRIM28 is identified as a substrate of MAP kinases that involves in vasopressin signaling pathways. TRIM28 is likely to play a role in the regulation of AQP2 expression, particularly in the AQP2 transcription.

Clinical Characteristics of Developmentally Delayed Children based on Interdisciplinary Evaluation

The aim of this study is to examine the clinical characteristics of children suspected to have neurodevelopmental disorders and to present features that could be helpful diagnostic clues at the clinical assessment stage. All children who visited the interdisciplinary clinic for developmental problems from May 2001 to December 2014 were eligible for this study. Medical records of the children were reviewed. A total of 1,877 children were enrolled in this study. Most children were classified into four major diagnostic groups: global developmental delay (GDD), autism spectrum disorder (ASD), developmental language disorder (DLD) and motor delay (MD). GDD was the most common (43.9%), and boys were significantly more predominant than girls in all groups. When evaluating the predictive power of numerous risk factors, the probability of GDD was lower than the probability of ASD among boys, while the probability of GDD increased as independent walking age increased. Compared with GDD and DLD, the probability of GDD was increased when there was neonatal history or when the independent walking age was late. Comparison of ASD and DLD showed that the probability of ASD decreased when a maternal history was present, whereas the probability of ASD increased with male gender. To conclude, the present study revealed the clinical features of children with various neurodevelopmental disorders. These results are expected to be helpful for more effectively flagging children with potential neurodevelopmental disorders in the clinical setting.

Exosomes co-expressing AQP5-targeting miRNAs and IL-4 receptor-binding peptide inhibit the migration of human breast cancer cells

Aquaporin-5 (AQP5) plays a role in breast cancer cell migration. This study aimed to identify AQP5-targeting miRNAs and examine their effects on breast cancer cell migration through exosome-mediated delivery. Bioinformatic analyses identified miR-1226-3p, miR-19a-3p, and miR-19b-3p as putative regulators of AQP5 mRNA. Immunoblotting revealed a decrease of AQP5 protein abundance when each of these miRNAs was transfected into human breast cancer MDA-MB-231 cells. Quantitative real-time PCR demonstrated the reduction of AQP5 mRNA expression by the transfection of miR-1226-3p and a luciferase reporter assay revealed the reduction of AQP5 translation after the transfection of miR-19b-3p in MDA-MB-231 cells. Consistently, the transfection of each miRNA impeded cell migration. Pathway enrichment analyses showed that these three miRNAs regulate target genes, which were predominantly enriched in the gap junction pathway. For the efficient delivery of AQP5-targeting miRNAs to breast cancer cells, exosomes expressing both miRNAs and a peptide targeting interleukin-4 receptor, which is highly expressed in breast cancer cells, were bioengineered and their inhibitory effects on AQP5 protein expression and cell migration were demonstrated in MDA-MB-231 cells. Taken together, AQP5-regulating miRNAs are identified, which could be exploited for the inhibition of breast cancer cell migration via the exosome-mediated delivery.

RNA-Seq and protein mass spectrometry in microdissected kidney tubules reveal signaling processes initiating lithium-induced nephrogenic diabetes insipidus

Lithium salts, used for treating bipolar disorder, frequently induce nephrogenic diabetes insipidus (NDI) thereby limiting therapeutic success. NDI is associated with loss of expression of the gene coding for the molecular water channel, aquaporin-2, in the renal collecting duct (CD). Here, we use systems biology methods in a well-established rat model of lithium-induced NDI to identify signaling pathways activated at the onset of polyuria. Using single-tubule RNA-Seq, full transcriptomes were determined in microdissected cortical collecting ducts (CCDs) of rats after 72 hours without or with initiation of lithium chloride administration. Transcriptome-wide changes in mRNA abundances were mapped to gene sets associated with curated canonical signaling pathways, showing evidence for activation of NF-κB signaling with induction of genes coding for multiple chemokines and most components of the Major Histocompatibility Complex Class I antigen-presenting complex. Administration of anti-inflammatory doses of dexamethasone to lithium chloride-treated rats countered the loss of aquaporin-2. RNA-Seq also confirmed prior evidence of a shift from quiescence into the cell cycle with arrest. Time course studies demonstrated an early (12 hour) increase in multiple immediate early response genes including several transcription factors. Protein mass spectrometry in microdissected CCDs provided corroborative evidence and identified decreased abundance of several anti-oxidant proteins. Thus, in the context of prior observations, our study can be best explained by a model in which lithium increases ERK activation leading to induction of NF-κB signaling and an inflammatory-like response that represses Aqp2 transcription.

Abstract 2594: Exosomes co-expressing aquaporin-5-targeting miRNAs and IL-4 receptor-binding peptide inhibit the migration of human breast cancer cells

Water channel aquaporins (AQPs) play a critical role in transcellular water transport. Recent studies revealed that dysregulation of AQPs is highly correlated with the migration of cancer cells and metastasis of tumor in vitro and in vivo models. In particular, we have demonstrated that increased expression of aquaporin-5 (AQP5) is associated with breast cancer cell migration, metastasis, and poor prognosis in human patients. We aimed to identify novel AQP5-targeting miRNAs and to examine the strategy for the post-transcriptional regulation of AQP5 using exosome-mediated microRNA (miRNA) delivery. Multiple tools of bioinformatics were used to identify AQP5-targeting miRNAs and miRNA target enrichment analysis revealed the cellular signaling pathways associated with the identified miRNAs. To examine the exosome-mediated miRNA delivery systems, exosomes containing both AQP5-targeting miRNAs and a peptide (CRKRLDRNC: IL-4RPep1) targeting the interleukin-4 receptor (IL-4R), which is highly expressed in breast cancer cells, were applied to triple-negative breast cancer cell line MDA-MB-231. Putative AQP5-targeting miRNAs were identified using DIANA Tool. Thereafter, three additional bioinformatic tools (TargetScan, miRDB and MiRanda Tools) were applied to select the miRNAs that were commonly identified from at least 3 different programs. Three miRNAs, miR-1226-3p, miR-19a-3p and miR-19b-3p, were identified as putative regulators of AQP5. Protein expression of AQP5 was decreased when mimic of each miRNA was transfected into MDA-MB-231 cells. Quantitative real-time PCR demonstrated a decrease of AQP5 mRNA expression by miR-1226-3p mimic and luciferase reporter assay revealed a reduction of AQP5 translation by miR-19b mimic in MDA-MB-231 cells. Consistently, cell migration was inhibited by mimic of each miRNA. miRNA target enrichment analysis showed that target genes of three miRNAs were predominantly enriched in the gap junction regulatory pathway. This suggested that these miRNAs are associated with breast cancer cell migration and, also, they might be involved in cell-cell adhesion. For the delivery of AQP5-targeting miRNAs to MDA-MB-231 cells, exosomes containing both AQP5-targeting miRNAs and a peptide (IL-4RPep1) were constructed in HEK293T cells. Both AQP5 protein expression and cell migration were significantly decreased in MDA-MB-231 cells when they were incubated with the exosome-containing culture media obtained from the culture of HEK293T cells expressing both AQP5-targeting miRNAs and IL-4RPep1. In conclusion, AQP5-regulating miRNAs are identified and their target genes are found to be mainly involved in the gap junction regulatory pathway. The exosome-mediated delivery of AQP5-targeting miRNAs could be exploited for the inhibition of breast cancer cell migration associated with AQP5.

Citation Format: Eui-Jung Park, Hyun Jun Jung, Hyo-Jung Choi, Hyo-Ju Jang, Hye-Jeong Park, Tae-Hwan Kwon. Exosomes co-expressing aquaporin-5-targeting miRNAs and IL-4 receptor-binding peptide inhibit the migration of human breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2594.

New insights into the transcriptional regulation of aquaporin-2 and the treatment of X-linked hereditary nephrogenic diabetes insipidus

The kidney collecting duct (CD) is a tubular segment of the kidney where the osmolality and final flow rate of urine are established, enabling urine concentration and body water homeostasis. Water reabsorption in the CD depends on the action of arginine vasopressin (AVP) and a transepithelial osmotic gradient between the luminal fluid and surrounding interstitium. AVP induces transcellular water reabsorption across CD principal cells through associated signaling pathways after binding to arginine vasopressin receptor 2 (AVPR2). This signaling cascade regulates the water channel protein aquaporin-2 (AQP2). AQP2 is exclusively localized in kidney connecting tubules and CDs. Specifically, AVP stimulates the intracellular translocation of AQP2-containing vesicles to the apical plasma membrane, increasing the osmotic water permeability of CD cells. Moreover, AVP induces transcription of the Aqp2 gene, increasing AQP2 protein abundance. This review provides new insights into the transcriptional regulation of the Aqp2 gene in the kidney CD with an overview of AVP and AQP2. It summarizes current therapeutic approaches for X-linked nephrogenic diabetes insipidus caused by AVPR2 gene mutations.

Representation and relative abundance of cell-type selective markers in whole-kidney RNA-Seq data

Bulk-tissue RNA-Seq is increasingly being used in the study of physiological and pathophysiological processes in the kidney; however, the presence of multiple cell types in kidney tissue complicates data interpretation. We addressed the question of which cell types are represented in whole-kidney RNA-Seq data in order to identify circumstances in which bulk-kidney RNA-Seq can be successfully interpreted. We carried out RNA-Seq in mouse whole kidneys and in microdissected renal tubule segments. To aid in the interpretation of the data, we compiled a database of cell-type selective protein markers for 43 cell types believed to be present in kidney tissue. The whole-kidney RNA-Seq analysis identified transcripts corresponding to 17,742 genes, distributed over 5 orders of magnitude of expression level. Markers for all 43 curated cell types were detectable. Analysis of the cellular makeup of mouse and rat kidney, calculated from published literature, suggests that proximal tubule cells account for more than half of the mRNA in a kidney. Comparison of RNA-Seq data from microdissected proximal tubules with data from whole kidney supports this view. RNA-Seq data for cell-type selective markers in bulk-kidney samples provide a valid means to identify changes in minority-cell abundances in kidney tissue. Because proximal tubules make up a substantial fraction of whole-kidney samples, changes in proximal tubule gene expression can be assessed presumptively by bulk-kidney RNA-Seq, although results could potentially be complicated by the presence of mRNA from other cell types.

Proteomic determination of the lysine acetylome and phosphoproteome in the rat native inner medullary collecting duct

Phosphorylation and lysine (K)-acetylation are dynamic posttranslational modifications of proteins. Previous proteomic studies have identified over 170,000 phosphorylation sites and 15,000 K-acetylation sites in mammals. We recently reported that the inner medullary collecting duct (IMCD), which functions in the regulation of water-reabsorption, via the actions of vasopressin, expresses many of the enzymes that can modulated K-acetylation. The purpose of this study was to determine the K-acetylated or phosphorylated proteins expressed in IMCD cells. Second we questioned whether vasopressin V2 receptor activation significantly affects the IMCD acetylome or phosphoproteome? K-acetylated or serine-, threonine-, or tyrosine-phosphorylated peptides were identified from native rat IMCDs by proteomic analysis with four different enzymes (trypsin, chymotrypsin, ASP-N, or Glu-C) to generate a high-resolution proteome. K-acetylation was identified in 431 unique proteins, and 64% of the K-acetylated sites were novel. The acetylated proteins were expressed in all compartments of the cell and were enriched in pathways including glycolysis and vasopressin-regulated water reabsorption. In the vasopressin-regulated water reabsorption pathway, eight proteins were acetylated, including the novel identification of the basolateral water channel, AQP3, acetylated at K282; 215 proteins were phosphorylated in this IMCD cohort, including AQP2 peptides that were phosphorylated at four serines: 256, 261, 264, and 269. Acute dDAVP did not significantly affect the IMCD acetylome; however, it did significantly affect previously known vasopressin-regulated phosphorylation sites. In conclusion, presence of K-acetylated proteins involved in metabolism, ion, and water transport in the IMCD points to multiple roles of K-acetylation beyond its canonical role in transcriptional regulation.

Genome-Wide Mapping of DNA Accessibility and Binding Sites for CREB and C/EBPβ in Vasopressin-Sensitive Collecting Duct Cells

Background Renal water excretion is controlled by vasopressin, in part through regulation of the transcription of the aquaporin-2 gene (Aqp2).Methods To identify enhancer regions likely to be involved in the regulation of Aqp2 and other principal cell-specific genes, we used several next generation DNA-sequencing techniques in a well characterized cultured cell model of collecting duct principal cells (mpkCCD). To locate enhancers, we performed the assay for transposase-accessible chromatin using sequencing (ATAC-Seq) to identify accessible regions of DNA and integrated the data with data generated by chromatin immunoprecipitation followed by next generation DNA-sequencing (ChIP-Seq) for CCCTC binding factor (CTCF) binding, histone H3 lysine-27 acetylation, and RNA polymerase II.Results We identified two high-probability enhancers centered 81 kb upstream and 5.8 kb downstream from the Aqp2 transcriptional start site. Motif analysis of these regions and the Aqp2 promoter identified several potential transcription factor binding sites, including sites for two b-ZIP transcription factors: CCAAT/enhancer binding protein-β (C/EBPβ) and cAMP-responsive element binding protein (CREB). To identify genomic binding sites for both, we conducted ChIP-Seq using well characterized antibodies. In the presence of vasopressin, C/EBPβ, a pioneer transcription factor critical to cell-specific gene expression, bound strongly at the identified enhancer downstream from Aqp2 However, over multiple replicates, we found no detectable CREB binding sites within 390 kb of Aqp2 Thus, any role for CREB in the regulation of Aqp2 gene transcription is likely to be indirect.Conclusions The analysis identified two enhancer regions pertinent to transcriptional regulation of the Aqp2 gene and showed C/EBPβ (but not CREB) binding.

Analysis of the number of enlarged pores according to site, age, and sex

BACKGROUND

Increasing the number of enlarged pores causes cosmetic problems. The difference in the number of enlarged pores according to facial site, age, and sex is unclear.

OBJECTIVE

To analyze the distribution of the number of enlarged pores according to facial site, age, and sex.

METHODS AND MATERIALS

We analyzed the number of the enlarged pores and the percentage of wrinkles in the nose, forehead, and cheek from 434 polarized images. The measurement results were analyzed according to site, age, and sex. Relationship between enlarged pore counts and wrinkle severity was also analyzed. The study was conducted by using DermaVision,™ which can take cross-polarization, parallel polarization, and ultraviolet light images.

RESULTS

The enlarged pores of the nose and forehead were more prominent than in the cheeks. Pore counts were increased with age, and the increment was significant between the 30's and 40's. There was no significant difference by gender. Enlarged pore counts were related to wrinkle severity.

CONCLUSIONS

The number of enlarged pores differs depending on body site and increased with age. The enlarged pore counts correlate with wrinkle severity and the correlation varies depending on the body site.

miR-34c-5p and CaMKII are involved in aldosterone-induced fibrosis in kidney collecting duct cells

Mineralocorticoids trigger a profibrotic process in the kidney. In mouse cortical collecting duct cells, the present study addressed two main questions: 1) what are microRNAs (miRNAs) and their target genes that are changed by aldosterone? and 2) what do miRNAs, in response to aldosterone, regulate regarding signaling pathways related to fibrosis? A microarray chip assay was done in cells in the absence or presence of aldosterone treatment (10^-6 M; 3 days). The candidate miRNAs were identified by the criteria of >30% of fold change among the significantly changed miRNAs ( P < 0.05). Twenty-nine miRNAs were upregulated (>1.3-fold), and 27 miRNAs were downregulated (<0.7-fold). Putative target genes of identified miRNAs were associated with 74 Kyoto Encyclopedia of Genes and Genomes pathways. Among them, the wingless-related integration site (Wnt) signaling pathway was highly ranked, where 15 mature miRNAs were observed. These miRNAs were further analyzed by real-time quantitative PCR, and among them, miR-130b-3p, miR-34c-5p, and miR-146a-5p were selected. Through the identification of putative target genes of these three miRNAs, mRNA and protein expression of the Ca²⁺/calmodulin-dependent protein kinase type II β-chain ( Camk2b) gene (a target gene of miR-34c-5p) were found to be increased significantly in aldosterone-treated cells, where fibronectin (FN) and α-smooth muscle actin were induced. When CaMKIIβ small interfering RNA or the miR-34c-5p mimic was transfected, aldosterone-induced FN expression was significantly attenuated, along with reduced CaMKIIβ protein expression. A luciferase reporter assay revealed a decrease of CaMKIIβ translation in cells transfected with miRNA mimics of miR-34c-5p. In conclusion, aldosterone-induced downregulation of miR-34c-5p in the Wnt signaling pathway and a consequent increase of CaMKIIβ expression are likely to be involved in aldosterone-induced fibrosis.

Identification of β-catenin-interacting proteins in nuclear fractions of native rat collecting duct cells

The gene encoding the aquaporin-2 water channel is regulated transcriptionally in response to vasopressin. In the renal collecting duct, vasopressin stimulates the nuclear translocation and phosphorylation (at Ser⁵⁵²) of β-catenin, a multifunctional protein that acts as a transcriptional coregulator in the nucleus. The purpose of this study was to identify β-catenin-interacting proteins that might be involved in transcriptional regulation in rat inner medullary collecting duct (IMCD) cells, using experimental and computational approaches. We used a standard chromatin immunoprecipitation procedure coupled to mass spectrometry (ChIP-MS) in a nuclear fraction isolated from rat IMCD suspensions. Over four biological replicates, we reproducibly identified 43 β-catenin-binding proteins, including several known β-catenin-binding partners as well as novel interacting proteins. Multiple proteins involved in transcriptional regulation were identified (Taf1, Jup, Tdrd3, Cdh1, Cenpj, and several histones). Many of the identified β-catenin-binding partners were found in prior studies to translocate to the nucleus in response to vasopressin. There was only one DNA-binding transcription factor (TF), specifically Taf1, part of the RNA-polymerase II preinitiation complex. To identify sequence-specific TFs that might interact with β-catenin, Bayes' theorem was used to integrate data from several information sources. The analysis identified several TFs with potential binding sites in the Aqp2 gene promoter that could interact with β-catenin in the regulation of Aqp2 gene transcription, specifically Jun, Junb, Jund, Atf1, Atf2, Mef2d, Usf1, Max, Pou2f1, and Rxra. The findings provide information necessary for modeling the transcriptional response to vasopressin.

The use of continuous negative pressure after open debridement for septic arthritis of the shoulder

AIMS

The treatment of septic arthritis of the shoulder is challenging. The infection frequently recurs and the clinical outcome can be very poor. We aimed to review the outcomes following the use of continuous negative pressure after open debridement with a large diameter drain in patients with septic arthritis of the shoulder.

PATIENTS AND METHODS

A total of 68 consecutive patients with septic arthritis of the shoulder underwent arthrotomy, irrigation and debridement. A small diameter suction drain was placed in the glenohumeral joint and a large diameter drain was placed in the subacromial space with continuous negative pressure of 15 cm H2O. All patients received a standardised protocol of antibiotics for a mean of 5.1 weeks (two to 11.1).

RESULTS

Negative pressure was maintained for a mean of 24 days (14 to 32). A total of 67 patients (98.5%) were cured without further treatment being required. At a mean follow-up of 14 months (three to 72), the mean forward flexion was 123° (80° to 140°) and the mean external rotation was 28°(10° to 40°) in those with a rotator cuff tear, and 125° (85° to 145°) and 35° (15° to 45°) in those without a rotator cuff tear.

CONCLUSION

Continuous negative pressure, following open arthrotomy, irrigation and debridement, was effective in treating septic arthritis of the shoulder. The rate of recurrence was significantly lower than with conventional treatment involving arthroscopic or open debridement reported in the literature. Functional outcomes, even in patients with rotator cuff tears, were excellent.

TAKE HOME MESSAGE

Continuous negative pressure is effective in treating septic arthritis of the shoulder. Cite this article: Bone Joint J 2016;98-B:660-5.

Undifferentiated embryonic cell transcription factor 1 (UTF1) and deleted in azoospermia-like (DAZL) expression in the testes of donkeys

Putative markers for each specific germ cell stage can be a useful tool to study the fate and functions of these cells. Undifferentiated embryonic cell transcription factor 1 (UTF1) is a putative marker for undifferentiated spermatogonia in humans, rats and horses. The deleted in azoospermia-like (DAZL) protein is also expressed by differentiated spermatogonia and primary spermatocytes in several species. However, whether the expression patterns of these molecular markers are identical and applicable to donkeys remains to be elucidated. The objective of this study was to investigate the expression patterns of UTF1 and DAZL in donkey testicular tissue, using immunohistochemistry (IHC). Testicular samples were collected from routine field castration of donkeys in Korea. The reproductive stages (pre- or post-puberty) of the testes were determined from the morphological characteristics of cross-sections of the seminiferous tubules. For IHC, the UTF1 and DAZL primary antibodies were diluted at 1:100 and 1:200, respectively. The immunolabelling revealed that UTF1 was expressed in approximately 50% of spermatogonia in the pre-pubertal stage, whereas its expression was limited to an early subset of spermatogonia in the post-pubertal stage. DAZL was expressed in some, but not all, spermatogonia in the pre-pubertal spermatogonia, and interestingly, its expression was also observed in spermatogonia and primary spermatocytes in the post-pubertal stage. Co-immunolabelling of the germ cells with both UTF1 and DAZL revealed three types of protein expression patterns at both reproductive stages, namely UTF1 only, DAZL only and both UTF1 and DAZL. These protein molecules were not expressed in Sertoli and Leydig cells. In conclusion, a co-immunolabelling system with UTF1 and DAZL antibodies may be used to identify undifferentiated (UTF1 only), differentiating (UTF1 and DAZL), and differentiated spermatogonia (DAZL only) in donkey testes.

Molecular mechanisms regulating aquaporin-2 in kidney collecting duct

The kidney collecting duct is an important renal tubular segment for regulation of body water homeostasis and urine concentration. Water reabsorption in the collecting duct principal cells is controlled by vasopressin, a peptide hormone that induces the osmotic water transport across the collecting duct epithelia through regulation of water channel proteins aquaporin-2 (AQP2) and aquaporin-3 (AQP3). In particular, vasopressin induces both intracellular translocation of AQP2-bearing vesicles to the apical plasma membrane and transcription of the Aqp2 gene to increase AQP2 protein abundance. The signaling pathways, including AQP2 phosphorylation, RhoA phosphorylation, intracellular calcium mobilization, and actin depolymerization, play a key role in the translocation of AQP2. This review summarizes recent data demonstrating the regulation of AQP2 as the underlying molecular mechanism for the homeostasis of water balance in the body.

Proteomic profiling of nuclear fractions from native renal inner medullary collecting duct cells

The control of renal water excretion occurs in part by regulation of transcription in response to vasopressin in cells of the collecting duct. A systems biology-based approach to understanding transcriptional control in renal collecting duct cells depends on knowledge of what transcription factors and other regulatory proteins are present in the cells' nuclei. The goal of this article is to report comprehensive proteomic profiling of cellular fractions enriched in nuclear proteins from native inner medullary collecting duct (IMCD) cells of the rat. Multidimensional separation procedures and state-of-the art protein mass spectrometry produced 18 GB of spectral data that allowed the high-stringency identification of 5,048 proteins in nuclear pellet (NP) and nuclear extract (NE) fractions of biochemically isolated rat IMCD cells (URL: https://helixweb.nih.gov/ESBL/Database/IMCD_Nucleus/). The analysis identified 369 transcription factor proteins out of the 1,371 transcription factors coded by the rat genome. The analysis added 1,511 proteins to the recognized proteome of rat IMCD cells, now amounting to 8,290 unique proteins. Analysis of samples treated with the vasopressin analog dDAVP (1 nM for 30 min) or its vehicle revealed 99 proteins in the NP fraction and 88 proteins in the NE fraction with significant changes in spectral counts (Fisher exact test, P < 0.005). Among those altered by vasopressin were seven distinct histone proteins, all of which showed decreased abundance in the NP fraction, consistent with a possible effect of vasopressin to induce chromatin remodeling. The results provide a data resource for future studies of vasopressin-mediated transcriptional regulation in the renal collecting duct.

The nutrition contribution of dietary supplements on total nutrient intake in children and adolescents

BACKGROUND/OBJECTIVES

The use of dietary supplements (DSs) by children and adolescents is increasing. The aim of this study was to identify the characteristics of DS users and examine the nutritional contributions of DSs to total nutrient intakes in children and adolescents, using data obtained from a national survey.

SUBJECTS/METHODS

In total, 3134 subjects aged 9-18 years who participated in the 4th Korea National Health and Nutrition Examination Survey (2007-2009) were selected; the survey included 24-h recall questions on food intake and questions on DS use over the past year. Nutrient intakes from DSs were calculated using the aid of a label-based database on such supplements, and individual total nutrient intakes were derived by combining information on the foods and DSs consumed by each subject.

RESULTS

There were 895 DS users (28.5%), 85.2% of whom (n=577) had complete DS nutrient information and were therefore defined as identified-DS users. Identified-DS users were slightly younger and had a greater household income and better nutritional knowledge than did non-users. The most frequently consumed type of supplement was a 'multivitamin and minerals' complex. For total nutrient intake, identified-DS users had a significantly higher intake of most of the nutrients, except for macronutrient and sodium than non-users. In all identified-DS users, the contribution of vitamins and minerals from DSs to total nutrient intake was higher than energy and macronutrients.

CONCLUSIONS

DS use by children and adolescents can improve micronutrient status, but it also increases the risk of excessive intake of certain vitamins and minerals.

Abstract P168: ChIP-seq Analysis of Genomic Binding Sites for the Transcription Factor Fosl2 in Kidney Collecting Duct Cells

Kidney collecting duct principal cells play a key role in blood pressure regulation and water balance in part through the action of vasopressin. We integrated data from prior proteomics and transcriptomics studies of cultured mouse mpkCCD cells using Bayes’ Rule to rank transcription factors (TFs) likely to be involved in vasopressin-mediated transcriptional regulation. The top ranked TF was the AP-1 component Fos-like 2 (Fosl2) and the third ranked TF was Sox4. We carried out ChIP-seq analysis (HiSeq 2000 sequencer) to identify genomic sites of Fosl2 binding using an antibody successfully employed for ChIP-seq in the Mouse ENCODE Project. mpkCCD cells treated with the vasopressin analog dDAVP or vehicle were separately analyzed. The success of the immunoprecipitation of Fosl2 was confirmed by western blotting and LC-MS/MS of the immuno-precipitated material (ChIP-MS). ChIP-MS identified two different Fosl2 peptides, but there were no peptides corresponding to other AP-1 proteins. ChIP-MS also identified Bub1b, a nuclear protein kinase known to phosphorylate histones, as a Fosl2-interacting protein. Fosl2-binding sites successfully mapped to genes by ChIP-seq included a Fosl2 binding site, centered at 87 bp upstream from the transcription start site [TSS] of Sox4, that was strongly downregulated in response to dDAVP, n=2; confirmed by ChIP-PCR. TF binding site prediction (Genomatix) identifies putative Sox4 binding sites in vasopressin-regulated genes beta-ENaC (-822 bp from TSS) and aquaporin-2 (-515 bp from TSS). These data provide an initial step in identification of the vasopressin-regulated transcriptional network in renal collecting duct cells.

A combination of excimer laser treatment and topical tacrolimus is more effective in treating vitiligo than either therapy alone for the initial 6 months, but not thereafter

BACKGROUND

There are insufficient data on the long-term outcome of a combination therapy that comprises phototherapy and topical administration of tacrolimus.

AIM

To evaluate the clinical efficacy according to the duration of treatment and in vitro results of a combination therapy involving topical tacrolimus and an excimer laser in the treatment of vitiligo.

METHODS

In total, 276 patients with nonsegmental vitiligo were treated with an excimer laser twice weekly, or with tacrolimus ointment twice daily, or both. The melanin contents and levels of melanogenic enzymes were measured in cultured human melanocytes treated with tacrolimus and/or excimer laser.

RESULTS

After adjusting for potential confounders, the combination of tacrolimus plus excimer laser was significantly more effective than either tacrolimus or excimer laser alone (P < 0.001 and P < 0.01, respectively) for the first 6 months. However, this superiority was not observed after the initial 6 months of treatment. In vitro, the combination of tacrolimus plus excimer laser led to a higher level of melanogenesis than with either treatment alone.

CONCLUSIONS

A combination treatment with topical tacrolimus and an excimer laser may be useful as an induction therapy for up to 6 months, but continuation of this therapy for > 6 months might not provide a better final outcome than monotherapy.