Principal Cells Research Articles

Altered firing output of VIP interneurons and early dysfunctions in CA1 hippocampal circuits in the 3xTg mouse model of Alzheimer's disease.

Alzheimer's disease (AD) leads to progressive memory decline, and alterations in hippocampal function are among the earliest pathological features observed in human and animal studies. GABAergic interneurons (INs) within the hippocampus coordinate network activity, among which type 3 interneuron-specific (I-S3) cells expressing vasoactive intestinal polypeptide and calretinin play a crucial role. These cells provide primarily disinhibition to principal excitatory cells (PCs) in the hippocampal CA1 region, regulating incoming inputs and memory formation. However, it remains unclear whether AD pathology induces changes in the activity of I-S3 cells, impacting the hippocampal network motifs. Here, using young adult 3xTg-AD mice, we found that while the density and morphology of I-S3 cells remain unaffected, there were significant changes in their firing output. Specifically, I-S3 cells displayed elongated action potentials and decreased firing rates, which was associated with a reduced inhibition of CA1 INs and their higher recruitment during spatial decision-making and object exploration tasks. Furthermore, the activation of CA1 PCs was also impacted, signifying early disruptions in CA1 network functionality. These findings suggest that altered firing patterns of I-S3 cells might initiate early-stage dysfunction in hippocampal CA1 circuits, potentially influencing the progression of AD pathology.

Urine Sample Handling in Laboratory—Process Reengineering is the Need of the Hour

Background and Aims: Monitoring and a continual improvement of turnaround time (TAT) in urine examination and reporting is essential for improved management of laboratory quality as well as ensuring patient satisfaction. TAT can be impacted by multiple factors, some of which appear to be beyond the control of laboratory, especially the preanalytical phase of urine examination such as specimen collection, transportation and sample preparation. The aim of the study was to compare the preanalytical variables like TAT for transportation and incidences of spill between our current urinalysis workflow process and the new urinalysis workflow process using a pneumatic chute-compatible closed urine collection system. Materials and Methods: This observational prospective study was conducted on 4/9/23 from 9 am to 4 pm at the laboratory of Apollo Main Hospital, Chennai. Pneumatic chute compatible closed urine collection cup was given to the patients in Group-A and normal screw cap containers which we are currently using were given to the patients in Group-B. Once the urine samples were collected in the respective containers, they were transported to the laboratory using pneumatic chutes for Group-A samples and manual carry for Group-B samples. Analysis of transportation time using the new collection method (Group-A) when compared with the current method of practice (Group-B) was done. The incidence of spillage was also monitored. Results: A significant improvement was noticed in the transportation process and spill incidence with closed collection devices through the pneumatic chute. Conclusion: To conclude, the implementation of pneumatic chute compatible closed collection tubes for urine improves the transportation and processing time, eliminates the manual carry of urine samples, eliminates the incidences of leakage and spillage, reduces errors and reduces the exposure of urine to healthcare workers, thereby leading to significant improvement in patient care, patient experience and staff satisfaction.

Urinary Extracellular Vesicles for Non-Invasive Quantification of Principal Cell Damage in Kidney Transplant Recipients.

The objective of the present study was to compare principal cell-specific aquaporin-2 (AQP2) abundances in urinary extracellular vesicles (uEVs) on the first postoperative day in deceased-donor kidney transplant recipients without and with acute kidney injury. We measured uEV markers (CD9 and CD63) and the abundances of proximal tubular sodium-glucose transporter 2, distal tubular sodium/chloride cotransporter, and principal cell-specific aquaporin-2 using Western blotting of urine. uEV-AQP2 levels were normalized to living donor controls. The validation cohort consisted of 82 deceased-donor kidney transplant recipients who had a median age of 50 years (IQR 43 to 57 years). A total of 32% of recipients had acute kidney injury. The median uEV-AQP2 was significantly higher in recipients with acute kidney injury compared to immediate allograft function (2.05; IQR 0.87 to 2.83; vs. 0.81; IQR 0.44 to 1.78; p < 0.01). The Youden index indicated a uEV-AQP2 threshold of 2.00. Stratifying uEV-AQP2 into quartiles showed that recipients with higher uEV-AQP2 levels had higher rates of acute kidney injury (Cochran-Armitage, p = 0.001). The discovery cohort showed elevated CD9, CD63, and uEV-AQP2 levels in urine from recipients with acute kidney injury compared to immediate allograft function. We were able to quantify the damage of principal cells after kidney transplant to predict acute kidney injury using uEV-AQP2.

Aurora A Kinase Begins to Localize to the Centrosome in the S-phase of the Cell Cycle in the XL2 Cell Line

Background: The centrosome is one of the principal cell hubs, where numerous proteins important for intracellular regulatory processes are concentrated. One of them, serine-threonine kinase 6, alias Aurora A, is involved in centrosome duplication and mitotic spindle formation and maintenance. Methods: Long-term vital observations of cells, immunofluorescence analysis of protein localization, synchronization of cells at different phases of the cell cycle, Western blot analysis of protein content were used in the work. Results: In this study, we investigated the dynamics of Aurora A protein accumulation and degradation in the XL2 Xenopus cell line during its 28-hour cell cycle. Using Western blot and immunofluorescence analyses, we demonstrated that Aurora A disappeared from the centrosome within one hour following mitosis and was not redistributed to other cell compartments. Using double Aurora A/Bromodeoxyuridine immunofluorescence labeling of the cells with precisely determined cell cycle stages, we observed that Aurora A reappeared in the centrosome during the S-phase, which was earlier than reported for all other known proteins with mitosis-specific centrosomal localization. Moreover, Aurora A accumulation in the centrosomal region and centrosome separation were asynchronous in the sister cells. Conclusions: The reported data allowed us to hypothesize that Aurora A is one of the primary links in coordinating centrosome separation and constructing the mitotic spindle.

A Possible Link between Cell Plasticity and Renin Expression in the Collecting Duct: A Narrative Review.

The hormone renin is produced in the kidney by the juxtaglomerular cells. It is the rate-limiting factor in the circulating renin-angiotensin-aldosterone system (RAAS), which contributes to electrolyte, water, and blood pressure homeostasis. In the kidneys, the distal tubule and the collecting duct are the key target segments for RAAS. The collecting duct is important for urine production and also for salt, water, and acid-base homeostasis. The critical functional role of the collecting duct is mediated by the principal and the intercalated cells and is regulated by different hormones like aldosterone and vasopressin. The collecting duct is not only a target for hormones but also a place of hormone production. It is accepted that renin is produced in the collecting duct at a low level. Several studies have described that the cells in the collecting duct exhibit plasticity properties because the ratio of principal to intercalated cells can change under specific circumstances. This narrative review focuses on two aspects of the collecting duct that remain somehow aside from mainstream research, namely the cell plasticity and the renin expression. We discuss the link between these collecting duct features, which we see as a promising area for future research given recent findings.

A morpho-viscoelasticity theory for growth in proliferating aggregates.

Despite significant research efforts in the continuum modeling of biological growth, certain aspects have been overlooked. For instance, numerous investigations have examined the influence of morphogenetic cell behaviors, like division and intercalation, on the mechanical response of passive (non-growing) tissues. Yet, their impact on active growth dynamics remains inadequately explored. A key reason for this inadequacy stems from challenges in the continuum treatment of cell-level processes. While some coarse-grained models have been proposed to address these shortcomings, a focus on cell division and cell expansion has been missing, rendering them unusable when it comes to modeling growth. Moreover, existing studies are limited to two-dimensional tissues and are yet to be formally extended to three-dimensional multicellular systems. To address these limitations, we here present a generalized multiscale model for three-dimensional aggregates that accounts for complex morphogenetic movements that include division, expansion, and intercalation. The proposed continuum theory thus allows for a comprehensive exploration into the growth and dissipation mechanics of proliferating aggregates, such as spheroids and organoids.

Decoding 11-Oxygenated Androgen Synthesis: Insights from Enzyme Gene Expression and LC‒MS/MS Quantification.

Adrenal-origin and peripheral tissue-transformed 11-oxygenated androgens are recognized as significant androgens. However, our current understanding of the synthesis of 11-oxygenated androgens, including the organs and cell types involved, remains limited. We performed comprehensive analyses on an extensive dataset of normal human tissues, which included bulk RNA data from 30 tissues, single-cell RNA sequencing (scRNA) data from 16 tissues and proteomics data from 29 tissues, to characterize the expression profiles of enzyme-encoding genes. To validate the findings, immunohistochemical and liquid chromatography-tandem mass spectrometry (LC‒MS/MS) techniques were employed. Our investigation revealed that the gene expression levels of the enzymes HSD11B2 and AKR1C3 were notably elevated in the kidney and intestines. Intriguingly, within these organs, we observed an increasing trend in enzyme expression with age in women, while a decreasing trend was apparent in men. Sc-RNA analysis revealed that HSD11B2 was predominantly expressed in collecting duct principal cells in the kidney, while AKR1C3 was primarily expressed in the proximal tubules. Intriguingly, nearly all epithelial cells in the intestine expressed these key enzymes. Further analysis using LC‒MS/MS revealed that the kidney exhibited the highest levels of 11-ketoandrostenedione (11KA4) and 11-ketotestosterone (11KT) among the seven tissues examined, and substantial synthesis of 11KA4 and 11KT was also observed in the intestine. Finally, we developed the TransMap website (http://gxmujyzmolab.cn:16245/TransMap/) to provide comprehensive visualization of all currently available transcriptome data. This study offers an overarching perspective on tracing the synthesis of 11-oxygenated androgens in peripheral tissues, thereby providing valuable insights into the potential role of these androgens in humans.

P100 ALPHA KETOGLUTARATE RECEPTOR 1 REGULATES THE EXPRESSION OF THE (PRO)RENIN RECEPTOR IN MEDULLARY RENAL TISSUES, MODULATES SODIUM EXCRETION AND ATTENUATES TWO-KIDNEY, ONE-CLIP GOLDBLATT HYPERTENSION IN MICE

Background: The two-kidney, one-clip (2K1C) Goldblatt model elicits a reduction of renal blood flow (RBF) in the clipped kidney (CK). The reduced RBF and oxygen bio ability causes the accumulation of the intermediary of the tricarboxylic cycle, α-ketoglutarate, which activates the oxoglutarate receptor-1 (OXGR1). In the kidney, the OXGR1 is abundantly expressed in intercalated cells (IC) of the collecting duct (CD), which may contribute to Na+ transport and electrolyte balance. The (pro)renin receptor (PRR), a member of the renin-angiotensin-aldosterone system is a key regulator of Na+ reabsorption, and blood pressure (BP) and is also expressed in IC. PRR is upregulated in 2K1C. Here, we tested the hypothesis that reduction of RBF in the CK leads to OXGR1-dependent PRR upregulation in the CD and alterations of Na+ balance and BP in 2K1C mice. Methods: To determine the role of OXGR1 in regulating PRR in the CDs during renovascular hypertension, we used 2K1C Goldblatt surgery (clip= 0.13 mm internal gap) in two groups of male mice: 1) Oxgr1-/- knockout (n=6) mice; and 2) mice treated with Montelukast (OXGR1 antagonist; 5 mg/Kg/day, n=6). WT and sham-operated mice were used as controls. Results: 2K1C mice showed increased systolic BP (SBP) (108 ± 11 vs. control 82 ± 5 mmHg, p&lt;0.01) and a lower natriuretic response after the saline challenge test. The CK showed augmented levels of α-ketoglutarate, erythropoietin mRNA levels, PRR (mRNA and protein abundances) in the renal medulla. Non-CK showed PRR upregulation in the CDs. However, the CK of Oxgr1-/- knockout mice, and from those subjected to OXGR1 antagonism, elicited impaired PRR upregulation, attenuated SBP (Oxgr1-/- 2K1C: 90 ± 8 mmHg, p=non-significant vs. control; Montelukast 2K1C: 95 ± 3 mmHg, p&lt;0.05 vs. control) and better natriuretic responses. Conclusion: In 2K1C mice, the effect of reduced RBF on the OXGR1-dependent PRR upregulation in the CK may contribute to the anti-natriuretic and increased SBP responses.

Abstract P201: Macula Densa (Pro)Renin Receptor Contributes to 2-Kidney, 1-Clip-Induced Renovascular Hypertension but not Ischemic Nephropathy in Mice

Our previous presentation at this meeting showed that collecting duct (CD)-specific deletion of (pro)renin receptor (PRR) or renin attenuated hypertension and kidney damage induced by the 2-kidney, 1 clip (2K1C) procedure, highlighting an essential role of the intrarenal renin-angiotensin system (RAS) in the pathogenesis of renovascular hypertension and ischemic nephropathy. Besides the CD, PRR is also expressed in the macula densa (MD), mediating renin release from the juxtaglomerular (JG) cells. Here we examined the phenotype of NKCC2-Cre-mediated MD/TAL-specific deletion of PRR (MD/TAL PRR KO) following the 2K1C procedure. Clipping-induced hypertension was partially attenuated in MD/TAL PRR KO mice compared to floxed controls (MAP on day 24: Floxed/2K1C 148.3±1.8 mm Hg vs. MD/TAL PRR KO/2K1C 138.8±2.9 mm Hg, n=6, p &lt; 0.05), to a similar degree in mice lacking PRR or renin in the CD. However, MD/TAL PRR KO mice did not exhibit protective effects against ischemic nephropathy compared to floxed controls following the 2K1C procedure (urinary albumin/creatinine: Floxed/2K1C 65.9 ± 4.6 mg/g vs. MD/TAL PRR KO/2K1C 59.5 ± 2.7 mg/g, n=6). Furthermore, there were no significant differences in clipping-induced protein abundance of renal fibronectin, α-SMA, or proinflammatory markers such as IL-1β, TNF-α, MCP-1. The protective phenotype against hypertension observed in KO mice was paralleled with suppressed plasma renin activity, active renin content, and total prorenin/renin levels. Additionally, while clipping upregulated renin mRNA expression in both renal cortex and medulla of floxed mice, only cortical renin expression was reduced by 39% in MD/TAL PRR KO mice. The 2K1C-induced increase in circulating sPRR was attenuated by 31% in MD/TAL PRR KO mice. Overall, our results suggest that renovascular hypertension in the 2K1C model is jointly determined by the systemic and intrarenal RAS whereas ischemic nephropathy in this model solely depends on the intrarenal RAS.

Effect of blood collection tube containing protease inhibitors on the pre-analytical stability of Alzheimer's disease plasma biomarkers.

The reliability of plasma biomarkers of Alzheimer's disease (AD) can be compromised by protease-induced degradation. This can limit the feasibility of conducting plasma biomarker studies in environments that lack the capacity for immediate processing and appropriate storage of blood samples. We hypothesized that blood collection tube supplementation with protease inhibitors can improve the stability of plasma biomarkers at room temperatures (RT). In this study, we conducted a comparative analysis of blood biomarker stability in traditional ethylenediaminetetraacetic acid (EDTA) tubes versus BD™ P100 collection tubes, the latter being coated with a protease inhibitor cocktail. The stability of six plasma AD biomarkers was evaluated over time under RT conditions. We evaluated three experimental approaches. In Approach 1, pooled plasma samples underwent storage at RT for up to 96 h. In Approach 2, plasma samples isolated upfront from whole blood collected into EDTA or P100 tubes were stored at RT for 0 h or 24 h before biomarker measurements. In Approach 3, whole blood samples were collected into paired EDTA and P100 tubes, followed by storage at RT for 0 h or 24 h before isolating the plasma for analyses. Biomarkers were measured with Single Molecule Array (Simoa) and immunoprecipitation-mass spectrometry (IP-MS) assays. Both the IP-MS and Simoa methods revealed that the use of P100 tubes significantly improves the stability of Aβ42 and Aβ40 across all approaches. However, the Aβ42/Aβ40 ratio levels were significantly stabilized only in the IP-MS assay in Approach 3. No significant differences were observed in the levels of plasma p-tau181, GFAP, and NfL for samples collected using either tube type in any of the approaches. Supplementation of blood collection tubes with protease inhibitors could reduce the protease-induced degradation of plasma Aβ42 and Aβ40, and the Aβ42/40 ratio for the IP-MS assay. These findings have crucial implications for preanalytical procedures, particularly in resource-limited settings.

Offline hippocampal reactivation during dentate spikes supports flexible memory.

Stabilizing new memories requires coordinated neuronal spiking activity during sleep. Hippocampal sharp-wave ripples (SWRs) in the cornu ammonis (CA) region and dentate spikes (DSs) in the dentate gyrus (DG) are prime candidate network events for supporting this offline process. SWRs have been studied extensively, but the contribution of DSs remains unclear. By combining triple-ensemble (DG-CA3-CA1) recordings and closed-loop optogenetics in mice, we show that, like SWRs, DSs synchronize spiking across DG and CA principal cells to reactivate population-level patterns of neuronal coactivity expressed during prior waking experience. Notably, the population coactivity structure in DSs is more diverse and higher dimensional than that seen during SWRs. Importantly, suppressing DG granule cell spiking selectively during DSs impairs subsequent flexible memory performance during multi-object recognition tasks and associated hippocampal patterns of neuronal coactivity. We conclude that DSs constitute a second offline network event central to hippocampal population dynamics serving memory-guided behavior.

Propagation of sharp wave-ripple activity in the mouse hippocampal CA3 subfield in vitro.

Sharp wave-ripple complexes (SPW-Rs) are spontaneous oscillatory events that characterize hippocampal activity during resting periods and slow-wave sleep. SPW-Rs are related to memory consolidation - the process during which newly acquired memories are transformed into long-lasting memory traces. To test the involvement of SPW-Rs in this process, it is crucial to understand how SPW-Rs originate and propagate throughout the hippocampus. SPW-Rs can originate in CA3, and they typically spread from CA3 to CA1, but little is known about their formation within CA3. To investigate the generation and propagation of SPW-Rs in CA3, we recorded from mouse hippocampal slices using multi-electrode arrays and patch-clamp electrodes. We characterized extracellular and intracellular correlates of SPW-Rs and quantified their propagation along the pyramidal cell layer of CA3. We found that a hippocampal slice can be described by a speed and a direction of propagation of SPW-Rs. The preferred propagation direction was from CA3c (the subfield closer to the dentate gyrus) toward CA3a (the subfield at the boundary to CA2). In patch-clamp recordings from CA3 pyramidal neurons, propagation was estimated separately for excitatory and inhibitory currents associated with SPW-Rs. We found that propagation speed and direction of excitatory and inhibitory currents were correlated. The magnitude of the speed of propagation of SPW-Rs within CA3 was consistent with the speed of propagation of action potentials in axons of CA3 principal cells. KEY POINTS: Hippocampal sharp waves are considered important for memory consolidation; therefore, it is of interest to understand the mechanisms of their generation and propagation. Here, we used two different approaches to study the propagation of sharp waves in mouse CA3 in vitro: multi-electrode arrays and multiple single-cell recordings. We find a preferred direction of propagation of sharp waves from CA3c toward CA3a - both in the local field potential and in sharp wave-associated excitatory and inhibitory synaptic activity. The speed of sharp wave propagation is consistent with the speed of action potential propagation along the axons of CA3 pyramidal neurons. These new insights into the dynamics of sharp waves in the CA3 network will inform future experiments and theoretical models of sharp-wave generation mechanisms.

Human efferent ductules and epididymis display unique cell lineages with motile and primary cilia.

Previous research has illustrated the role of cilia as mechanical and sensory antennae in various organs within the mammalian male reproductive system across different developmental stages. Despite their significance in both organ development and homeostasis, primary cilia in the human male reproductive excurrent duct have been overlooked due to limited access to human specimens. This study aimed to characterize the unique cellular composition of human efferent and epididymal ducts, with a focus on their association with primary cilia. Human efferent ductules/epididymides from five donors aged 32-47 years, were obtained through our local organ transplant program. Cell lineage specificity and primary cilia features were examined by immunofluorescent staining and confocal microscopy in the efferent ductules and the distinct segments of the epididymis. The epithelium of the human efferent duct exhibited estrogen receptor-positive cells with primary cilia, FoxJ1-positive multiciliated cells with numerous motile cilia, and non-ciliated intraepithelial immune cells. Notably, intraluminal macrophages, identified by CD163/CD68 positivity, were observed to engage in sperm phagocytosis. In all three segments of the human epididymis, primary cilia were found on the surface of principal and basal cells. Our research indicates that the human efferent ductules create a distinct environment, characterized by the presence of two types of ciliated cells that are in contact with immune cells. The discovery of sensory primary cilia exposed on the surface of reabsorptive cells in the efferent ductules, as well as on basal and principal cells in the epididymis, lays the foundation for complementary functional studies. This research uncovers novel characteristics exclusive to human efferent ductules and epididymides, providing a basis for exploring innovative approaches to male contraception and infertility treatment.

Report of a case of renal collecting duct carcinoma with literature review

Collecting duct carcinoma (CDC) is a rare pathologic subtype of renal cell carcinoma that accounts for approximately 0.4–1% of cases and originates in the collecting ducts (Bellini ducts) of the renal medulla. The majority of patients are metastatic at the time of presentation, extremely malignant and rapidly progressive, with most patients dying 1–3 years after initial diagnosis. Currently, surgery is considered the only effective treatment. There is no uniform standard for postoperative adjuvant radiotherapy and chemotherapy.In this article, we report a case of an 85-year-old female patient with CDC who underwent radical nephrectomy. This is an extremely rare case. We describe the case and perform a literature review to report current research advances regarding the treatment and prognosis of patients with CDC. The aim of this study is to contribute to improving the diagnosis and treatment of CDC.

Dynamic changes in pyroptosis following spinal cord injury and the identification of crucial molecular signatures through machine learning and single-cell sequencing

The pathological cascade of spinal cord injury (SCI) is highly intricate. The onset of neuroinflammation can exacerbate the extent of damage. Pyroptosis is a form of inflammation-linked programmed cell death (PCD), the inhibition of pyroptosis can partially mitigate neuroinflammation. It is imperative to delineate the principal cell types susceptible to pyroptosis and concomitantly identify key genes associated with this process. We initially defined the pyroptosis-related genes (PRGs) and analyzed their expression at different time points post SCI. The results demonstrate a substantial upregulation of differentially expressed genes (DEGs) related to pyroptosis on the 7 days post-injury (dpi), these DEGs in the 7 dpi are closely related to the inflammatory response. Subsequently, immune infiltration analysis revealed a predominant presence of inflammatory microglia. Through correlation analysis, we postulated that pyroptosis primarily manifested within the inflammatory microglia. Employing machine learning algorithms, we identified four pyroptosis-related molecular signatures, which were experimentally validated using BV2 cells and spinal cord tissue samples. The robustness of the identified molecular signatures was further confirmed through single-cell sequencing data analysis. Overall, our study elucidates the temporal dynamics of pyroptosis and identifies key molecular signatures following SCI. These findings can provide novel evidence for therapeutic interventions in SCI.

Tranilast Treatment Prevents Chronic Radiation-Induced Colitis in Rats by Inhibiting Mast Cell Infiltration

Introduction: Mast cells are the principal cells involved in acute and chronic colitis due to radiation, known as radiation-induced colitis (RIC). In this study, we investigated whether pretreatment with tranilast, a mast cell inhibitor, could alleviate chronic RIC. Methods: A total of 23 Sprague-Dawley rats were randomly divided into three groups: control group (n = 5), radiation group (RG, n = 9), and tranilast-pretreated radiation group (TG, n = 9). The rats in the RG and the TG were irradiated in the pelvic area (1.5 cm from the anus) with a single dose of 20 Gy under general anesthesia. Tranilast (100 mg/kg) was administered intraperitoneally to the rats of the TG for 10 days, starting from the day of pelvic radiation. Ten weeks after radiation, the rats were euthanized. Rectal tissue samples were histologically evaluated for the total inflammation score (TIS) and mast cell count. The expression of MUC2, MUC5AC, and matrix metalloproteinase-9 (MMP-9) was also assessed immunohistochemically. Results: Both the TIS and specific components of TIS such as epithelial atypia, vascular sclerosis, and colitis cystica profunda (CCP) were significantly higher in the RG than in the TG (p = 0.02, 0.038, 0.025, and 0.01, respectively). Thein number of infiltrating mast cells was significantly higher in the RG than in the TG (median [range]: 20 [3−54] versus 6 [3−25], respectively; p = 0.034). Quantitatively, the number of MMP-9-positive cells was significantly higher in the RG (23.67 ± 19.00) than in the TG (10.25 ± 8.45) (mean ± standard deviation; p < 0.05). TIS and MMP-9 exhibited a strong association (correlation coefficient r = 0.56, p < 0.05). Immunohistochemically, the mucin-lake of CCP showed no staining for MUC5AC but was stained positive for MUC2. Conclusion: Tranilast pretreatment of chronic RIC showed an anti-inflammatory effect associated with the reduction of mast cell infiltration and MMP-9 expression.

Effects of long-term dehydration and quick rehydration on the camel kidney: pathological changes and modulation of the expression of solute carrier proteins and aquaporins

BackgroundRecurrent dehydration causes chronic kidney disease in humans and animal models. The dromedary camel kidney has remarkable capacity to preserve water and solute during long-term dehydration. In this study, we investigated the effects of dehydration and subsequent rehydration in the camel's kidney histology/ultrastructure and changes in aquaporin/solute carrier proteins along with gene expression.ResultsIn light microscopy, dehydration induced few degenerative and necrotic changes in cells of the cortical tubules with unapparent or little effect on medullary cells. The ultrastructural changes encountered in the cortex were infrequent during dehydration and included nuclear chromatin condensation, cytoplasmic vacuolization, mitochondrial swelling, endoplasmic reticulum/ lysosomal degeneration and sometimes cell death. Some mRNA gene expressions involved in cell stability were upregulated by dehydration. Lesions in endothelial capillaries, glomerular membranes and podocyte tertiary processes in dehydrated camels indicated disruption of glomerular filtration barrier which were mostly corrected by rehydration. The changes in proximal tubules brush borders after dehydration, were accompanied by down regulation of ATP1A1 mRNA involved in Na + /K + pump that were corrected by rehydration. The increased serum Na, osmolality and vasopressin were paralleled by modulation in expression level for corresponding SLC genes with net Na retention in cortex which were corrected by rehydration. Medullary collecting ducts and interstitial connective tissue were mostly unaffected during dehydration. CKD, a chronic nephropathy induced by recurrent dehydration in human and animal models and characterized by interstitial fibrosis and glomerular sclerosis, were not observed in the dehydrated/rehydrated camel kidneys. The initiating factors, endogenous fructose, AVP/AVPR2 and uric acid levels were not much affected. TGF-β1 protein and TGF-β1gene expression showed no changes by dehydration in cortex/medulla to mediate fibrosis. KCNN4 gene expression level was hardly detected in the dehydrated camel's kidney; to encode for Ca + + -gated KCa3.1 channel for Ca + + influx to instigate TGF-β1. Modulation of AQP 1, 2, 3, 4, 9 and SLC protein and/or mRNAs expression levels during dehydration/rehydration was reported.ConclusionsLong-term dehydration induces reversible or irreversible ultrastructural changes in kidney cortex with minor effects in medulla. Modulation of AQP channels, SLC and their mRNAs expression levels during dehydration/rehydration have a role in water conservation. Cortex and medulla respond differently to dehydration/rehydration.

Modeling the roles of cohesotaxis, cell-intercalation, and tissue geometry in collective cell migration of Xenopus mesendoderm.

Collectively migrating Xenopus mesendoderm cells are arranged into leader and follower rows with distinct adhesive properties and protrusive behaviors. In vivo, leading row mesendoderm cells extend polarized protrusions and migrate along a fibronectin matrix assembled by blastocoel roof cells. Traction stresses generated at the leading row result in the pulling forward of attached follower row cells. Mesendoderm explants removed from embryos provide an experimentally tractable system for characterizing collective cell movements and behaviors, yet the cellular mechanisms responsible for this mode of migration remain elusive. We introduce a novel agent-based computational model of migrating mesendoderm in the Cellular-Potts computational framework to investigate the respective contributions of multiple parameters specific to the behaviors of leader and follower row cells. Sensitivity analyses identify cohesotaxis, tissue geometry, and cell intercalation as key parameters affecting the migration velocity of collectively migrating cells. The model predicts that cohesotaxis and tissue geometry in combination promote cooperative migration of leader cells resulting in increased migration velocity of the collective. Radial intercalation of cells towards the substrate is an additional mechanism contributing to an increase in migratory speed of the tissue. Model outcomes are validated experimentally using mesendoderm tissue explants.

Validation of low-volume blood collection tubes for routine hematologic testing

Validation of low-volume blood collection tubes for routine hematologic testing

Evaluation of polypropylene CSF low-bind collection tubes for trace metal contamination.

Due to the ability of metal ions to cross the blood-brain barrier, there has been interest in analyzing cerebrospinal fluid (CSF) for trace element concentrations to investigate possible correlations with neurodegenerative diseases. In this study, Sarstedt polypropylene CSF collection tubes were analyzed to determine the contamination levels of aluminum, titanium, chromium, manganese, cobalt, nickel, molybdenum, gadolinium, vanadium, arsenic, cadmium, mercury, lead, thallium, selenium, copper, zinc, and iron. Sarstedt polypropylene CSF collection tubes from 2 separate lots (n = 10 per lot) were filled with a 2 mL aliquot of a CSF pool with known element concentrations. After 24 hours of leaching at room temperature, all 18 elements were analyzed via inductively coupled plasma mass spectrometry (ICP-MS). Results were subtracted from the initial pool concentration to determine contamination levels. No detectable contamination above the assay limit of detection was found in 11 analytes. Molybdenum and selenium contamination was measured in all tubes, and aluminum, titanium, manganese, thallium, and zinc had minimal levels of sporadic detectable contamination in 25% or fewer of the tubes tested. Sarstedt polypropylene CSF tubes are an acceptable collection tube for the analysis of most assessed metals in CSF.