Mouse Kidney Research Articles

Visualization of intracellular ATP dynamics in different nephron segments under pathophysiological conditions using the kidney slice culture system

ATP depletion plays a central role in the pathogenesis of kidney diseases. Recently, we reported spatiotemporal intracellular ATP dynamics during ischemia reperfusion (IR) using GO-ATeam2 mice systemically expressing an ATP biosensor. However, observation from the kidney surface did not allow visualization of deeper nephrons or accurate evaluation of ATP synthesis pathways. Here, we established a novel ATP imaging system using slice culture of GO-ATeam2 mouse kidneys, evaluated the ATP synthesis pathway, and analyzed intracellular ATP dynamics using an exvivo IR-mimicking model and a cisplatin nephropathy model. Proximal tubules (PTs) were found to be strongly dependent on oxidative phosphorylation (OXPHOS) using the inhibitor oligomycin A, whereas podocytes relied on both OXPHOS and glycolysis using phloretin an active transport inhibitor of glucose. We also confirmed that an exvivo IR-mimicking model could recapitulate ATP dynamics invivo; ATP recovery in PTs after reoxygenation varied depending on anoxic time length, whereas ATP in distal tubules (DTs) recovered well even after long-term anoxia. After cisplatin administration, ATP levels in PTs decreased first, followed by a decrease in DTs. An organic cation transporter 2 inhibitor, cimetidine, suppressed cisplatin uptake in kidney slices, leading to better ATP recovery in PTs, but not in DTs. Finally, we confirmed that a mitochondria protection reagent (Mitochonic Acid 5) delayed the cisplatin-induced ATP decrease in PTs. Thus, our novel system may provide new insights into the energy dynamics and pathogenesis of kidney disease.

Insulin receptor orchestrates kidney antibacterial defenses

Urinary tract infection (UTI) commonly afflicts people with diabetes. This augmented infection risk is partly due to deregulated insulin receptor (IR) signaling in the kidney collecting duct. The collecting duct is composed of intercalated cells (ICs) and principal cells (PCs). Evidence suggests that ICs contribute to UTI defenses. Here, we interrogate how IR deletion in ICs impacts antibacterial defenses against uropathogenic Escherichia coli. We also explore how IR deletion affects immune responses in neighboring PCs with intact IR expression. To accomplish this objective, we profile the transcriptomes of IC and PC populations enriched from kidneys of wild-type and IC-specific IR knock-out mice that have increased UTI susceptibility. Transcriptomic analysis demonstrates that IR deletion suppresses IC-integrated stress responses and innate immune defenses. To define how IR shapes these immune defenses, we employ murine and human kidney cultures. When challenged with bacteria, murine ICs and human kidney cells with deregulated IR signaling cannot engage central components of the integrated stress response-including activating transcriptional factor 4 (ATF4). Silencing ATF4 impairs NFkB activation and promotes infection. In turn, NFkB silencing augments infection and suppresses antimicrobial peptide expression. In diabetic mice and people with diabetes, collecting duct cells show reduced IR expression, impaired integrated stress response engagement, and compromised immunity. Collectively, these translational data illustrate how IR orchestrates collecting duct antibacterial responses and the communication between ICs and PCs.

Inhibition of PKC-δ retards kidney fibrosis via inhibiting cGAS-STING signaling pathway in mice

Kidney fibrosis is considered to be the ultimate aggregation pathway of chronic kidney disease (CKD), but its underlying mechanism remains elusive. Protein kinase C-delta (PKC-δ) plays critical roles in the control of growth, differentiation, and apoptosis. In this study, we found that PKC-δ was highly upregulated in human biopsy samples and mouse kidneys with fibrosis. Rottlerin, a PKC-δ inhibitor, alleviated unilateral ureteral ligation (UUO)-induced kidney fibrosis, inflammation, VDAC1 expression, and cGAS-STING signaling pathway activation. Adeno-associated virus 9 (AAV9)-mediated VDAC1 silencing or VBIT-12, a VDAC1 inhibitor, attenuated renal injury, inflammation, and activation of cGAS-STING signaling pathway in UUO mouse model. Genetic and pharmacologic inhibition of STING relieved renal fibrosis and inflammation in UUO mice. In vitro, hypoxia resulted in PKC-δ phosphorylation, VDAC1 oligomerization, and activation of cGAS-STING signaling pathway in HK-2 cells. Inhibition of PKC-δ, VDAC1 or STING alleviated hypoxia-induced fibrotic and inflammatory responses in HK-2 cells, respectively. Mechanistically, PKC-δ activation induced mitochondrial membrane VDAC1 oligomerization via direct binding VDAC1, followed by the mitochondrial DNA (mtDNA) release into the cytoplasm, and subsequent activated cGAS-STING signaling pathway, which contributed to the inflammation leading to fibrosis. In conclusion, this study has indicated for the first time that PKC-δ is an important regulator in kidney fibrosis by promoting cGAS-STING signaling pathway which mediated by VDAC1. PKC-δ may be useful for treating renal fibrosis and subsequent CKD.

Tirzepatide alleviates oxidative stress and inflammation in diabetic nephropathy via IL-17 signaling pathway.

Oxidative stress (OS) and inflammation play essential roles in the development of diabetic nephropathy (DN). Tirzepatide (TZP) has a protective effect in diabetes. However, its underlying mechanism in DN remains unclear. DN model mice were induced by intraperitoneal injection of streptozotocin (STZ; 60mg/kg), followed by administration of different doses of TZP (3 and 10nmol/kg) via intraperitoneal injection for 8weeks. The effects of TZP on DN were evaluated by detecting DN-related biochemical indicators, kidney histopathology, apoptosis, OS, and inflammation levels. Additionally, to further reveal the potential mechanism, we investigated the role of TZP in modulating the IL-17 pathway. TZP reduced serum creatinine (sCR), blood urea nitrogen (BUN), and advanced glycosylation end products (AGEs) levels, while simultaneously promoting insulin secretion in diabetic mice. Additionally, TZP attenuated tubular and glomerular injury and reduced renal apoptosis levels. Further studies found that TZP increased the levels of SOD and CAT, and decreased MDA. Meanwhile, TZP also reduced the expression of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in both mouse serum and kidney homogenates. TZP effectively inhibited the IL-17 pathway, and subsequent intervention with an IL-17 pathway agonist (IL-17A) reversed the suppressive effects of TZP on OS and inflammation. TZP can improve DN by inhibiting OS and inflammation through the suppression of the IL-17 pathway.

Tissue-resident memory T cells break tolerance to renal autoantigens and orchestrate immune-mediated nephritis

Immune-mediated nephritis is a leading cause of acute kidney injury and chronic kidney disease. While the role of B cells and antibodies has been extensively investigated in the past, the advent of immune-checkpoint inhibitors has led to a reappraisal of the role of T cells in renal immunology. However, it remains elusive how T cells with specificity for renal autoantigens are activated and participate in immune-mediated nephritis. Here, we followed the fate and function of pathogen-activated autoreactive CD8 T cells that are specific for a renal autoantigen. We demonstrate that recently activated splenic CD8 T cells developed a hybrid phenotype in the context of renal autoantigen cross-presentation, combining hallmarks of activation and T cell dysfunction. While circulating memory T cells rapidly disappeared, tissue-resident memory T cells emerged and persisted within the kidney, orchestrating immune-mediated nephritis. Notably, T cells infiltrating kidneys of patients with interstitial nephritis also expressed key markers of tissue residency. This study unveils how a tissue-specific immune response can dissociate from its systemic counterpart driving a compartmentalized immune response in the kidneys of mice and man. Consequently, targeting tissue-resident memory T cells emerges as a promising strategy to control immune-mediated kidney disease.

The cytochrome P4501A1 (CYP1A1) inhibitor bergamottin enhances host tolerance to multidrug-resistant Vibrio vulnificus infection

PurposeVibrio vulnificus (V. Vulnificus) infection is characterized by rapid onset, aggressive progression, and challenging treatment. Bacterial resistance poses a significant challenge for clinical anti-infection treatment and is thus the subject of research. Enhancing host infection tolerance represents a novel infection prevention strategy to improve patient survival. Our team initially identified cytochrome P4501A1 (CYP1A1) as an important target owing to its negative modulation of the body's infection tolerance. This study explored the superior effects of the CYP1A1 inhibitor bergamottin compared to antibiotic combination therapy on the survival of mice infected with multidrug-resistant V. Vulnificus and the protection of their vital organs. MethodsAn increasing concentration gradient method was used to induce multidrug-resistant V. Vulnificus development. We established a lethal infection model in C57BL/6J male mice and evaluated the effect of bergamottin on mouse survival. A mild infection model was established in C57BL/6J male mice, and the serum levels of creatinine, urea nitrogen, aspartate aminotransferase, and alanine aminotransferase were determined using enzyme-linked immunosorbent assay to evaluate the effect of bergamottin on liver and kidney function. The morphological changes induced in the presence of bergamottin in mouse organs were evaluated by hematoxylin and eosin staining of liver and kidney tissues. The bacterial growth curve and organ load determination were used to evaluate whether bergamottin has a direct antibacterial effect on multidrug-resistant V. Vulnificus. Quantification of inflammatory factors in serum by enzyme-linked immunosorbent assay and the expression levels of inflammatory factors in liver and kidney tissues by real-time quantitative polymerase chain reaction were performed to evaluate the effect of bergamottin on inflammatory factor levels. Western blot analysis of IκBα, phosphorylated IκBα, p65, and phosphorylated p65 protein expression in liver and kidney tissues and in human hepatocellular carcinomas-2 and human kidney-2 cell lines was used to evaluate the effect of bergamottin on the nuclear factor kappa-B signaling pathway. One-way ANOVA and Kaplan-Meier analysis were used for statistical analysis. ResultsIn mice infected with multidrug-resistant V. Vulnificus, bergamottin prolonged survival (p = 0.014), reduced the serum creatinine (p = 0.002), urea nitrogen (p = 0.030), aspartate aminotransferase (p = 0.029), and alanine aminotransferase (p = 0.003) levels, and protected the cellular morphology of liver and kidney tissues. Bergamottin inhibited interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α expression in serum (IL-1β: p = 0.010, IL-6: p = 0.029, TNF-α: p = 0.025) and inhibited the protein expression of the inflammatory factors IL-1β, IL-6, TNF-α in liver (IL-1β: p = 0.010, IL-6: p = 0.011, TNF-α: p = 0.037) and kidney (IL-1β: p = 0.016, IL-6: p = 0.011, TNF-α: p = 0.008) tissues. Bergamottin did not affect the proliferation of multidrug-resistant V. Vulnificus or the bacterial load in the mouse peritoneal lavage fluid (p = 0.225), liver (p = 0.186), or kidney (p = 0.637). ConclusionBergamottin enhances the tolerance of mice to multidrug-resistant V. Vulnificus infection. This study can serve as a reference and guide the development of novel clinical treatment strategies for V. Vulnificus.

Optimizing a mouse model of exertional heat stroke to simulate multiorgan and brain injuries.

Exertional heat stroke (EHS) is a clinical entity characterized by abnormalities of the central nervous system (CNS) and is associated with multiple organ injury, some of which may be irreversible. It is valuable to establish an optimized model of EHS that is able to induce and assess damage to the CNS and multiple organs. We induced EHS by using an environmental chamber with adjustable temperature and humidity and a mice forced running wheel. The endpoint for the EHS was defined as either exhaustion or a core temperature of 42.5°C being reached. Injury to the liver, kidney, and CNS of mice in the EHS group was revealed through pathological studies using hematoxylin and eosin staining of harvested organs at different time points and detection of biomarkers. The depressive-like behavior of EHS mice was assessed through open field tests, forced swimming tests, and tail suspension tests. The favorable environmental conditions for induction of EHS based on this presented model are 38°C, 70% RH. The EHS mice developed thermoregulatory dysfunction and experienced a significantly higher weight loss ratio compared to the SHE (sham heat exercise) group. The liver, kidney, and brain tissues of EHS mice were significantly damaged, and the pathological damage scores for each organ were significantly higher than those of the SHE group. In the open field test (OFT), compared to the SHE group, there was a significant reduction in the number and time of EHS mice entering the center of the open field. Additionally, there was a significant increase in immobile time during forced swimming test (FST) and tail suspension test (TST). This study presents an improved animal model that has the potential to assess for neurological and multiple organ injury caused by EHS and simultaneously, while accurately reflecting the clinical characteristics observed in EHS patients.

Retinoic acid reduces kidney injury by regulating oxidative stress, NRF-2, and apoptosis in hyperoxic mice.

Nuclear factor-erythroid-2-related factor-2 (NRF-2) is a cellular resistance protein to oxidants. We investigated the effect of exogenous all-trans retinoic acid (ATRA) on the antioxidant system and NRF-2 in mice kidneys under hyperoxia-induced oxidative stress. Mice were divided into four groups. Daily, two groups were given either peanut-oil/dimethyl sulfoxide (PoDMSO) mixture or 50 mg/kg ATRA. Oxidative stress was induced by hyperoxia in the remaining groups. They were treated with PoDMSO or ATRA as described above, following hyperoxia (100% oxygen) for 72 h. NRF-2 and active-caspase-3 levels, lipid peroxidation (LPO), activities of antioxidant enzymes, xanthine oxidase (XO), paraoxonase1 (PON1), lactate dehydrogenase (LDH), tissue factor (TF), and prolidase were assayed in kidneys. Hyperoxia causes kidney damage induced by oxidative stress and apoptosis. Increased LPO, LDH, TF, and XO activities and decreased PON1 and prolidase activities contributed to kidney damage in hyperoxic mice. After hyperoxia, increases in the activities of antioxidant enzymes and NRF-2 level could not prevent this damage. ATRA attenuated damage via its oxidative stress-lowering effect. The decreased LDH and TF activities increased PON1 and prolidase activities, and normalized antioxidant statuses are indicators of the positive effects of ATRA. We recommend that ATRA can be used as a renoprotective agent against oxidative stress induced-kidney damage.

Enhancing the nutritional value and antioxidant properties of foxtail millet by solid‐state fermentation with edible fungi

AbstractFoxtail millet is typically dehulled before consumption or processing. However, foxtail millet bran also contains abundant phenolic compounds and other nutrients. Edible fungi have rich extracellular enzyme systems; are environmentally friendly and safe for consumption; and have been shown to effectively degrade lignin and cellulose. This study aimed to screen edible fungi that can effectively ferment undehusked foxtail millet, improving its nutritional value and antioxidant properties through solid‐state fermentation (SSF). The results demonstrated that fermentation utilizing Pleurotus geesteranus exhibited significant improvements in both the phenolic compound content and antioxidant properties of foxtail millet, with the optimal fermentation period determined to be 30 days. The physical and functional properties of fermented undehusked foxtail millet (FFM) flour were effectively improved, increasing crude protein, vitamin C, and crude polysaccharide contents by 11.46%, 27.78%, and 54.17%, respectively. In vitro scavenging activities of FFM were 73.19%, 93.86%, and 63.75% for 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS·+), and superoxide anion radicals (O2−), respectively. The total antioxidant capability (T‐AOC) and superoxide dismutase (SOD) activity of FFM were 1.01 mM Trolox equivalents (TE)/g and 89.05 U/g, respectively. Additionally, T‐AOC, SOD, and glutathione peroxidase (GSH‐Px) activities increased, whereas malondialdehyde (MDA) levels decreased in the heart, liver, and kidneys of mice treated with FFM flour, indicating enhanced antioxidant capacity. Therefore, fermentation with edible fungi is suitable for improving the nutritional composition and antioxidant properties of foxtail millet.

Line-scanning microscopy with laterally symmetric imaging using simultaneous cross-line illumination

Using an on-the-fly scanning scheme, line confocal microscopy can obtain complex structures of large biological tissues with high throughput. Yet, it suffers from lateral imaging asymmetry and thus introduces the potential deformations of the observation results. Here, we propose cross-line illumination microscopy (cLIM) that acquires the imaging data of two perpendicular directions simultaneously through the same objective lens in a line scanning and utilizes two-direction deconvolution fusion to achieve lateral symmetric imaging performance. Imaging fluorescence beads indicates that cLIM reduces lateral resolution asymmetry from 46.1% to 2.5% and improves lateral resolution by 31.0%, compared with traditional line-scanning imaging. Compared with commercial point-confocal microscopy, the cLIM has a 25.84× increase in imaging speed and 1.93× better background-suppressing ability when imaging an 11,306 μm×7783 μm×100 μm mouse kidney slice. We also show the advantages of the cLIM in observing direction-sensitive texture features by imaging a muscular tissue slice. cLIM offers a novel solution to achieve laterally symmetric line-scanning imaging with simple modifications while maintaining high throughput and accuracy for imaging large-scale samples.

Andrias davidianus bone peptides alleviates hyperuricemia-induced kidney damage in vitro and in vivo

Hyperuricemia (HUA) is a vital risk factor for chronic kidney diseases (CKD) and development of functional foods capable of protecting CKD is of importance. This paper aimed to explore the amelioration effects and mechanism of Andrias davidianus bone peptides (ADBP) on HUA-induced kidney damage. In the present study, we generated the standard ADBP which contained high hydrophobic amino acid and low molecular peptide contents. In vitro results found that ADBP protected uric acid (UA)-induced HK-2 cells from damage by modulating urate transporters and antioxidant defense. In vivo results indicated that ADBP effectively ameliorated renal injury in HUA-induced CKD mice, evidenced by a remarkable decrease in serum UA, creatinine and blood urea nitrogen, improving kidney UA excretion, antioxidant defense and histological kidney deterioration. Metabolomic analysis highlighted 14 metabolites that could be selected as potential biomarkers and attributed to the amelioration effects of ADBP on CKD mice kidney dysfunction. Intriguingly, ADBP restored the gut microbiome homeostasis in CKD mice, especially with respect to the elevated helpful microbial abundance, and the decreased harmful bacterial abundance. This study demonstrated that ADBP displayed great nephroprotective effects, and has great promise as a food or functional food ingredient for the prevention and treatment of HUA-induced CKD.

Cannabidiol attenuates arsenic-induced nephrotoxicity via the NOX4 and NF-κB pathways in mice.

Cannabidiol (CBD) is a phenolic terpene compound with anticancer, antioxidant, anti-inflammatory, antibacterial, neuroprotective, and anticonvulsant properties. Since the effects of CBD on sodium arsenite (As)-induced nephrotoxicity have not been fully determined, this study investigated the effect of CBD on As-induced nephrotoxicity by evaluating the NOX4 and NF-kB pathways in mice. 48 male mice were divided into six groups (8 each) including group 1, receiving saline for 14 days; group 2, receiving CBD (10 mg/kg, intraperitoneally) from the 7th to the 14th day; group 3, receiving As (10 mg/kg) for 14 days by gavage; and treatment groups 4-6, receiving CBD (2.5, 5, and 10 mg/kg, i.p.) 1.5 h before As (10 mg/kg by gavage, for 14 days) from the 7th to the 14th day. Mice were anesthetized after overnight fasting on day 15, and the blood sample was collected from their hearts. The level of antioxidants and pro-inflammatory factors, the expression of ROS and TNF-α, NF-kB, NOX4, iNOS, cleaved PARP, and caspase-3 proteins were measured and histological studies were performed. Exposure to As significantly increased kidney markers, oxidative stress, apoptosis, and inflammation in mice kidney tissue, and pretreatment with CBD reversed these changes. In addition, CBD significantly decreased the expression of NF-kB and NOX4, and the levels of pro-inflammatory factors and the expression of cleaved PARP and increased the level of antioxidants. CBD ameliorated As-induced nephrotoxicity related to inhibiting oxidative stress, inflammation, and apoptosis, potentially through the NF-kB/Nox4 pathway.

TRIM65 deficiency alleviates renal fibrosis through NUDT21-mediated alternative polyadenylation.

Chronic kidney disease (CKD) is a major global health concern and the third leading cause of premature death. Renal fibrosis is the primary process driving the progression of CKD, but the mechanisms behind it are not fully understood, making treatment options limited. Here, we find that the E3 ligase TRIM65 is a positive regulator of renal fibrosis. Deletion of TRIM65 results in a reduction of pathological lesions and renal fibrosis in mouse models of kidney fibrosis induced by unilateral ureteral obstruction (UUO)- and folic acid. Through screening with a yeast-hybrid system, we identify a new interactor of TRIM65, the mammalian cleavage factor I subunit CFIm25 (NUDT21), which plays a crucial role in fibrosis through alternative polyadenylation (APA). TRIM65 interacts with NUDT21 to induce K48-linked polyubiquitination of lysine 56 and proteasomal degradation, leading to the inhibition of TGF-β1-mediated SMAD and ERK1/2 signaling pathways. The degradation of NUDT21 subsequently altered the length and sequence content of the 3'UTR (3'UTR-APA) of several pro-fibrotic genes including Col1a1, Fn-1, Tgfbr1, Wnt5a, and Fzd2. Furthermore, reducing NUDT21 expression via hydrodynamic renal pelvis injection of adeno-associated virus 9 (AAV9) exacerbated UUO-induced renal fibrosis in the normal mouse kidneys and blocked the protective effect of TRIM65 deletion. These findings suggest that TRIM65 promotes renal fibrosis by regulating NUDT21-mediated APA and highlight TRIM65 as a potential target for reducing renal fibrosis in CKD patients.

Role of MARK4 in methamphetamine-induced acute kidney injury.

Methamphetamine (METH) is an illicit psychoactive substance that can damage various organs, with the urinary system being one of its significant targets. This study aims to explore the role of microtubule affinity-regulating kinase 4 (MARK4) in METH-induced acute kidney injury (AKI). A total of 10 healthy adult male C57BL/6 mice were randomly divided into a control group and a METH group, 5 mice in each group. The METH group was administered METH (20 mg/kg, intraperitoneally, once daily for 3 consecutive days), while the control group received an equal volume of physiological saline. The mice were executed 24 hours after the final injection, and the success of the AKI model was detected by blood serum creatinine, blood urea nitrogen, and renal HE staining. Proteins differentially expressed between kidney tissues with METH-induced AKI and normal kidney tissues were screened by proteomics techniques and subjected to gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and bioinformatics analysis. The accuracy of proteomic data was validated using Western blotting, and the expression levels of MARK4 and cleaved caspase-3 in mouse kidneys were measured. We further explored the role of MARK4 in METH-induced AKI. Firstly, a METH toxicity model was established in BUMPT cells to screen the appropriate concentration and time of METH treatment; the viability of BUMPT cells after METH treatment and the expression of cleaved caspase-3 were detected by interfering with MARK4 expression through inhibitors. The proteomic analysis of kidney tissues from METH and control groups screened for a total of 17 differentially expressed proteins, of which 11 were up-regulated and 6 were down-regulated (all P<0.05). The expression levels of MARK4 and cleaved caspase-3 were elevated in the kidneys of METH-treated mice (both P<0.05). The activity of BUMPT cells gradually decreased with increasing METH treatment concentration (all P<0.05), where the viability of BUMPT cells decreased to about 60% after METH treatment at 4 mmol/L. Compared with the control group, expression levels of MARK4 and cleaved caspase-3 were increased with higher METH concentrations and longer exposure times in a concentration- and time-dependent manner (all P<0.05). Inhibition of MARK4 expression improved METH-induced decrease in BUMPT cell activity, down-regulated the expression of cleaved caspase-3, and decreased the apoptosis of BUMPT cells induced by METH. MARK4 is highly expressed in a mouse model of METH-induced AKI, and MARK4 mediates METH-induced AKI by regulating cell apoptosis.

Saps1-3 Antigens in Candida albicans: Differential Modulation Following Exposure to Soluble Proteins, Mammalian Cells, and Infection in Mice.

The secreted aspartic peptidases (Saps) of Candida albicans play crucial roles in various steps of fungal-host interactions. Using a flow cytometry approach, this study investigated the expression of Saps1-3 antigens after (i) incubation with soluble proteins, (ii) interaction with mammalian cells, and (iii) infection in immunosuppressed BALB/c mice. Supplementation strategies involving increasing concentrations of bovine serum albumin (BSA) added to yeast carbon base (YCB) medium as the sole nitrogenous source revealed a positive and significant correlation between BSA concentration and both the growth rate and the percentage of fluorescent cells (%FC) labeled with anti-Saps1-3 antibodies. Supplementing the YCB medium with various soluble proteins significantly modulated the expression of Saps1-3 antigens in C. albicans. Specifically, immunoglobulin G, gelatin, and total bovine/human sera significantly reduced the %FC, while laminin, human serum albumin, fibrinogen, hemoglobin, and mucin considerably increased the %FC compared to BSA. Furthermore, co-cultivating C. albicans yeasts with either live epithelial or macrophage cells induced the expression of Saps1-3 antigens in 78% (mean fluorescence intensity [MFI] = 152.1) and 82.7% (MFI = 178.2) of the yeast cells, respectively, compared to BSA, which resulted in 29.3% fluorescent cells (MFI = 50.9). Lastly, the yeasts recovered from the kidneys of infected immunosuppressed mice demonstrated a 4.8-fold increase in the production of Saps1-3 antigens (MFI = 246.6) compared to BSA, with 95.5% of yeasts labeled with anti-Saps1-3 antibodies. Altogether, these results demonstrated the positive modulation of Saps' expression in C. albicans by various key host proteinaceous components, as well as by in vitro and in vivo host challenges.

Nitroreductase-Triggered Fluorophore Labeling of Cells and Tissues under Hypoxia.

Several reductases, including nitroreductase, are upregulated under hypoxic conditions characterized by an oxygen-deficient microenvironment. Given that hypoxia is a prominent feature of solid tumors, our investigation focused on developing a bioconjugative probe designed for staining tissue under hypoxic conditions, particularly activated by nitroreductase. This probe, developed using our trigger-release-bioconjugation system rooted in the ortho-quinone methide chemistry, exhibited selective activation by nitroreductase and fluorophore labeling within mitochondria and endoplasmic reticulum. As a result, it displayed sustained fluorescence that persisted even after washing steps in cells and tissues. We applied this innovative probe to stain mouse kidney tissue in an acute kidney injury model induced by inadequate oxygen supply. Among various organ tissues examined, only kidney tissue showed significantly higher fluorescence in the injury model compared with the control tissue, as revealed by two-photon microscopic imaging. This research presents a promising avenue for the development of practical staining agents for image-guided tumor surgery.

Role of the Anaphylatoxin Receptor C5aR2 in Angiotensin II-Induced Hypertension and Hypertensive End-Organ Damage.

Complement activation may facilitate hypertension through its effects on immune responses. The anaphylatoxin C5a, a major inflammatory effector, binds to the C5a receptors 1 and 2 (C5aR1, C5aR2). We have recently shown that C5aR1-/- mice have reduced hypertensive renal injury. The role of C5aR2 in hypertension is unknown. For examination of C5aR2 expression on infiltrating and resident renal cells a tandem dye Tomato-C5aR2 knock-in reporter mouse was used. Human C5aR2 expression was analyzed in a single-cell RNAseq data set from the kidneys of hypertensive patients. Finally, we examined the effect of angiotensin II-induced hypertension in C5aR2-deficient mice. Flow cytometric analysis of leukocytes isolated from kidneys of the reporter mice showed that dendritic cells are the major C5aR2-expressing population (34%) followed by monocyte/macrophages (30%) and neutrophils (14%). Using confocal microscopy C5aR2 was not detected in resident renal or cardiac cells. In the human kidney, C5aR2 was also mainly found in monocytes, macrophages, and dendritic cells with a significantly higher expression in hypertension (P < 0.05). Unilateral nephrectomy was performed followed by infusion of Ang II (0.75 ng/g/min) and a high salt diet in wildtype (n = 18) and C5aR2-deficient mice (n = 14). Blood pressure, renal injury (albuminuria, glomerular filtration rate, glomerular and tubulointerstitial injury, inflammation), and cardiac injury (cardiac fibrosis, heart weight, gene expression) did not differ between hypertensive wildtype and C5aR2-/- mice. In summary, C5aR2 is mainly expressed in myeloid cells in the kidney in mice and humans but its deficiency has no effect on Ang II-induced hypertensive injury.

Swine Influenza Viruses Isolated from 2019 to 2022 in Shandong Province, China, Exemplify the Dominant Genotype.

Swine influenza viruses (SIVs) have been circulating in swine globally and are potential threats to human health. During the surveillance of SIVs in Shandong Province, China, from 2019 to 2022, 21 reassortant G4 genotype Eurasian avian-like (EA) H1N1 subtypes containing genes from the EA H1N1 (HA and NA), 2009 pandemic (pdm/09) H1N1 virus (PB2, PB1, PA, NP, and M), and classical swine (CS) H1N1 (NS) lineages were isolated. The analysis of the key functional amino acid sites in the isolated viruses showed that two mutation sites (190D and 225E) that preferentially bind to the human α2-6 sialic acid receptor were found in HA. In PB2, three mutation sites (271A, 590S, and 591R) that may increase mammalian fitness and a mutation site (431M) that increases pathogenicity in mice were found. A typical human signature marker that may promote infection in humans, 357K, was found in NP. The viruses could replicate efficiently in mouse lungs and turbinates, and one of the H1N1 isolates could replicate in mouse kidneys and brains without prior adaption, which indicates that the viruses potentially pose a threat to human health. Histopathological results showed that the isolated viruses caused typical bronchopneumonia and encephalitis in mice. The results indicate that G4 genotype H1N1 has potential transmissibility to humans, and surveillance should be enhanced, which could provide important information for assessing the pandemic potential of the viruses.

Evaluation of the acute and sub-acute toxicity of the standardized extract of Avicennia officinalis L. in mice

Avicennia officinalis L. (AOL) has shown promise for its anti-inflammatory, anti-cancer, and antioxidant properties. However, there is no research on the toxicity of this plant in Vietnam. The acute and sub-acute toxicology study proved that AOL leaf extracts are practically non-toxic in normal mice. Acute toxicity assessment was conducted with single oral doses of AOL extract (2500, 3100, 4100, and 5000 mg/kg). In sub-acute toxicity, mice were administered daily oral doses of AOL extract (200 and 400 mg/kg) for 28 days. Blood was collected from the heart, liver, and kidneys for further analysis. The comprehensive results revealed an oral median lethal dose (LD50) exceeding 5000 mg/kg, indicating low acute toxicity. A sub-acute study (200 and 400 mg/kg/day) showed no deaths or weight gain. At both doses, the standardized AOL extracts decreased serum aspartate transaminase activity. Administration of the 200 mg/kg group significantly increased blood urea levels; however, histological examination of mouse kidneys in this group revealed no signal of damage. Histological examination of mouse livers revealed mild degeneration, possibly due to the use of adult mice and potentially unrelated to the extract. This study emphasizes AOL's potential for further pharmacological testing based on its low acute toxicity and promising results.

Injury-induced Foxm1 expression in the mouse kidney drives epithelial proliferation by a cyclin F-dependent mechanism.

Acute kidney injury (AKI) strongly upregulates the transcription factor Foxm1 in the proximal tubule in vivo, and Foxm1 drives epithelial proliferation in vitro. Here, we report that deletion of Foxm1 either with a nephron-specific Cre driver or by inducible global deletion reduced proximal tubule proliferation after ischemic injury in vivo. Foxm1 deletion led to increased AKI to chronic kidney disease transition, with enhanced fibrosis and ongoing tubule injury 6 weeks after injury. We report ERK mediated FOXM1 induction downstream of the EGFR in primary proximal tubule cells. We defined FOXM1 genomic binding sites by cleavage under targets and release using nuclease (CUT&RUN) and compared the genes located near FOXM1 binding sites with genes downregulated in primary proximal tubule cells after FOXM1 knockdown. The aligned data sets revealed the cell cycle regulator cyclin F (CCNF) as a putative FOXM1 target. We identified 2 cis regulatory elements that bound FOXM1 and regulated CCNF expression, demonstrating that Ccnf is strongly induced after kidney injury and that Foxm1 deletion abrogates Ccnf expression in vivo and in vitro. Knockdown of CCNF also reduced proximal tubule proliferation in vitro. These studies identify an ERK/FOXM1/CCNF signaling pathway that regulates injury-induced proximal tubule cell proliferation.