Pkd2 Deficiency in Embryonic Aqp2 + Progenitor Cells Is Sufficient to Cause Severe Polycystic Kidney Disease.

SIGNIFICANCE STATEMENT: Autosomal dominant polycystic kidney disease (ADPKD) is a devastating disorder caused by mutations in polycystin 1 ( PKD1 ) and polycystin 2 ( PKD2 ). Currently, the mechanism for renal cyst formation remains unclear. Here, we provide convincing and conclusive data in mice demonstrating that Pkd2 deletion in embryonic Aqp2 + progenitor cells (AP), but not in neonate or adult Aqp2 + cells, is sufficient to cause severe polycystic kidney disease (PKD) with progressive loss of intercalated cells and complete elimination of α -intercalated cells, accurately recapitulating a newly identified cellular phenotype of patients with ADPKD. Hence, Pkd2 is a new potential regulator critical for balanced AP differentiation into, proliferation, and/or maintenance of various cell types, particularly α -intercalated cells. The Pkd2 conditional knockout mice developed in this study are valuable tools for further studies on collecting duct development and early steps in cyst formation. The finding that Pkd2 loss triggers the loss of intercalated cells is a suitable topic for further mechanistic studies. BACKGROUND: Most cases of autosomal dominant polycystic kidney disease (ADPKD) are caused by mutations in PKD1 or PKD2. Currently, the mechanism for renal cyst formation remains unclear. Aqp2 + progenitor cells (AP) (re)generate ≥5 cell types, including principal cells and intercalated cells in the late distal convoluted tubules (DCT2), connecting tubules, and collecting ducts. METHODS: Here, we tested whether Pkd2 deletion in AP and their derivatives at different developmental stages is sufficient to induce PKD. Aqp2Cre Pkd2f/f ( Pkd2AC ) mice were generated to disrupt Pkd2 in embryonic AP. Aqp2ECE/+Pkd2f/f ( Pkd2ECE ) mice were tamoxifen-inducted at P1 or P60 to inactivate Pkd2 in neonate or adult AP and their derivatives, respectively. All induced mice were sacrificed at P300. Immunofluorescence staining was performed to categorize and quantify cyst-lining cell types. Four other PKD mouse models and patients with ADPKD were similarly analyzed. RESULTS: Pkd2 was highly expressed in all connecting tubules/collecting duct cell types and weakly in all other tubular segments. Pkd2AC mice had obvious cysts by P6 and developed severe PKD and died by P17. The kidneys had reduced intercalated cells and increased transitional cells. Transitional cells were negative for principal cell and intercalated cell markers examined. A complete loss of α -intercalated cells occurred by P12. Cysts extended from the distal renal segments to DCT1 and possibly to the loop of Henle, but not to the proximal tubules. The induced Pkd2ECE mice developed mild PKD. Cystic α -intercalated cells were found in the other PKD models. AQP2 + cells were found in cysts of only 13/27 ADPKD samples, which had the same cellular phenotype as Pkd2AC mice. CONCLUSIONS: Hence, Pkd2 deletion in embryonic AP, but unlikely in neonate or adult Aqp2 + cells (principal cells and AP), was sufficient to cause severe PKD with progressive elimination of α -intercalated cells, recapitulating a newly identified cellular phenotype of patients with ADPKD. We proposed that Pkd2 is critical for balanced AP differentiation into, proliferation, and/or maintenance of cystic intercalated cells, particularly α -intercalated cells.

Preliminary study of finger temperature recovery in patients with diabetes mellitus following cold stimulation.

OBJECTIVE: To explore the difference in temperature recovery following cold stimulation between participants with and without diabetes mellitus (DM). MATERIALS AND METHODS: The participants without (control group; n = 25) and with (DM group; n = 26) DM were subjected to local cold stimulation (10º C for 90 s). The thermal images of their hands were continuously captured using a thermal camera within 7 min following cold stimulation, and the highest temperature of each fingertip was calculated. According to the temperature values at different timepoints, the temperature recovery curves were drawn, and the baseline temperature (T-base), initial temperature after cooling (T0), temperature decline amplitude (T-range), and area under the temperature recovery curve > T0 (S) were calculated. Finally, symmetry differences between the two groups were analysed. RESULTS: No statistical differences in the T-base, T0, and T-range were observed between the DM and control groups. After drawing the rewarming curve according to the temperature of the fingertips of the patients following cold stimulation, the S in the DM group was significantly lower than that in the control group (p < 0.05). Furthermore, the asymmetry of the base temperature of the hand was observed in the DM group. CONCLUSIONS: Following cold stimulation, the patients with DM exhibited a different rewarming pattern than those without DM. Thus, cold stimulation tests under infrared thermography may contribute to the early screening of diabetic peripheral neuropathy in future.

Bridging the gap: coordinating equity and efficiency in older people care resource allocation in China.

BACKGROUND: With the increasing global aging population, how to allocate older people care resources reasonably has become an increasingly urgent international issue. China, as the largest developing country, has made many efforts to actively respond to the challenges of an aging population. However, there are still problems with uneven allocation of older people care resources and low efficiency of allocation. Therefore, this study evaluates the regional differences and dynamic evolution of the equity and efficiency of older people care resource allocation in China from 2009 to 2020, and explores ways to change the current situation. METHODS: The data used in this study were derived from the "China Statistical Yearbook" and the "China Civil Affairs Statistical Yearbook" for the period of 2010-2021. Firstly, the equity of older people care resource allocation was measured using the Gini coefficient, the Theil index, the Older People Care Resource Density Index, and the Older People Care Resource Agglomeration Degree. Secondly, the dynamic Slack-Based Measure data envelopment analysis method was adopted to evaluate efficiency. Lastly, the Z-score is used to normalize the equity index and perform classification matching with the efficiency value. Spatial autocorrelation analysis and hotspot analysis were conducted using GIS technology to examine the dynamic evolution process of older people care resource allocation equity and efficiency, as well as their spatial distribution patterns and coordination across provinces from 2009 to 2020. RESULTS: The equity analysis showed that the spatial distribution of various types of older people care resources was uneven, and the differences were mainly due to internal differences within each region, with the largest equity differences observed in western provinces. Currently, older people care resources are mainly concentrated in eastern regions, while the total amount of older people care resources in western regions and some central regions is relatively small, which cannot meet the older people care needs of residents. The efficiency analysis results showed that the efficiency of older people care resource allocation has been improving over the past 12 years, and in 2020, 77.42% of provinces were located on the efficiency frontier with an average efficiency value of 0.9396. Finally, the coordination analysis results showed that there were significant spatiotemporal differences in the equity and efficiency of older people care resources allocation. CONCLUSION: With the development of society and economy, the total amount and service capacity of older people care resources in China have greatly improved. However, there are still significant spatiotemporal differences in the equity and efficiency of older people care resource allocation. The development of older people care services in central and eastern provinces is unbalanced, and there is a polarization trend in terms of equity and efficiency of older people care resource allocation. Most provinces in western regions face the dual dilemma of inadequate older people care resources and low utilization efficiency. It is recommended that policymakers comprehensively consider population and geographic factors in different provinces, establish relevant allocation standards according to local conditions, improve the redistribution system, and focus on increasing the total amount of older people care resources in underdeveloped provinces while promoting resource flow.

What determines informal care need among community-dwelling older adults in China? Results from a longitudinal study.

BACKGROUND: With an intensified aging population and an associated upsurge of informal care need in China, there is an ongoing discussion around what factors influence this need among older adults. Most existing studies are cross-sectional and do not focus on older people living in the community. Conversely, this study empirically explores the factors that affect informal care need of Chinese community-dwelling older individuals based on longitudinal data. METHODS: This study constructed panel data using the China Health and Retirement Longitudinal Research Study (CHARLS) from 2011 to 2018 for analysis. Generalized linear mixed models were used to analyze the factors affecting reception of informal care, and linear mixed models were used to analyze the factors affecting informal care sources and intensity. RESULTS: During the follow-up period, 7542, 6386, 5087, and 4052 older adults were included in 2011-2018, respectively. The proportion receiving informal care increased from 19.92 to 30.78%, and the proportion receiving high-intensity care increased from 6.42 to 8.42% during this period. Disability (estimate = 4.27, P < 0.001) and living arrangement (estimate = 0.42, P < 0.001) were the critical determinants of informal care need. The rural older adults reported a greater tendency to receive informal care (estimate = 0.14, P < 0.001). However, financial support from children did not affect informal care need (P > 0.05). CONCLUSIONS: At present, there is a great demand for the manpower and intensity of informal care, and the cost of informal care is on the rise. There are differences in informal care needs of special older groups, such as the oldest-old, living alone and severely disabled. In the future, the region should promote the balance of urban and rural care service resources, rationally tilt economic support resources to rural areas, reduce the inequality of long-term care resources, improve the informal care support system, and provide a strong community guarantee for the local aging of the older adults.

Atomic-scale observation of non-classical nucleation-mediated phase transformation in a titanium alloy.

Two-phase titanium-based alloys are widely used in aerospace and biomedical applications, and they are obtained through phase transformations between a low-temperature hexagonal closed-packed α-phase and a high-temperature body-centred cubic ß-phase. Understanding how a new phase evolves from its parent phase is critical to controlling the transforming microstructures and thus material properties. Here, we report time-resolved experimental evidence, at sub-ångström resolution, of a non-classically nucleated metastable phase that bridges the α-phase and the ß-phase, in a technologically important titanium-molybdenum alloy. We observed a nanosized and chemically ordered superstructure in the α-phase matrix; its composition, chemical order and crystal structure are all found to be different from both the parent and the product phases, but instigating a vanishingly low energy barrier for the transformation into the ß-phase. This latter phase transition can proceed instantly via vibrational switching when the molybdenum concentration in the superstructure exceeds a critical value. We expect that such a non-classical phase evolution mechanism is much more common than previously believed for solid-state transformations.

Compound Kushen Injection Reduces Severe Toxicity and Symptom Burden Associated With Curative Radiotherapy in Patients With Lung Cancer.

BACKGROUND: Radiotherapy (RT) causes adverse events for which there are no effective treatments. This study investigated the clinical benefits of compound Kushen injection (CKI) in managing radiation injury in patients with lung cancer. METHODS: A multicenter, open-label, randomized clinical trial randomly assigned patients with lung cancer to receive either CKI (20 mL/d for at least 4 weeks) integrated with curative RT (RT + CKI group; n=130) or RT alone (control group; n=130). The primary outcome was the incidence of grade ≥2 radiation-induced lung injury (RILI) in the lungs, esophagus, or heart. Secondary outcomes included patient-reported symptoms, quality of life, objective response rate (ORR), and toxic effects. RESULTS: During the 16-week trial, the RT + CKI group had a significantly lower incidence of grade ≥2 RT-related injury than the control group (12.3% [n=16] vs 23.1% [n=30]; P=.02). Compared with the control group, the RT + CKI group experienced a significant decrease in moderate-to-severe symptoms of fatigue, cough, and pain (P<.001 for the treatment and time interaction term); significantly less physical symptom interference (P=.01); and significantly better quality of life by the end of the trial (P<.05). No statistically significant difference in ORR was found. Adverse reactions associated with CKI were rare. CONCLUSIONS: This study demonstrated low toxicity of CKI and its effectiveness in patients with lung cancer in reducing the incidence of grade ≥2 RILI and symptom burden, improving patients' quality of life.

Aqp2+ Progenitor Cells Maintain and Repair Distal Renal Segments.

BACKGROUND: Adult progenitor cells presumably demonstrate clonogenicity, self-renewal, and multipotentiality, and can regenerate cells under various conditions. Definitive evidence demonstrating the existence of such progenitor cells in adult mammalian kidneys is lacking. METHOD: We performed in vivo lineage tracing and thymidine analogue labeling using adult tamoxifen-inducible (Aqp2ECE/+ RFP/+, Aqp2ECE/+ Brainbow/+, and Aqp2ECE/+ Brainbow/Brainbow) and WT mice. The tamoxifen-inducible mice were analyzed between 1 and 300 days postinduction. Alternatively, WT and tamoxifen-induced mice were subjected to unilateral ureteral obstruction and thymidine analogue labeling and analyzed 2-14 days post-surgery. Multiple cell-specific markers were used for high-resolution immunofluorescence confocal microscopy to identify the cell types derived from Aqp2+ cells. RESULTS: Like their embryonic counterparts, adult cells expressing Aqp2 and V-ATPase subunits B1 and B2 (Aqp2+ B1B2+) are the potential Aqp2+ progenitor cells (APs). Adult APs rarely divide to generate daughter cells, either maintaining the property of the AP (self-renewal) or differentiating into DCT2/CNT/CD cells (multipotentiality), forming single cell-derived, multiple-cell clones (clonogenicity) during tissue maintenance. APs selectively and continuously regenerate DCT2/CNT/CD cells in response to injury resulting from ureteral ligation. AP proliferation demonstrated direct correlation with Notch activation and was inversely correlated with development of kidney fibrosis. Derivation of both intercalated and DCT2 cells was found to be cell division-dependent and -independent, most likely through AP differentiation which requires cell division and through direct conversion of APs and/or regular principal cells without cell division, respectively. CONCLUSION: Our study demonstrates that Aqp2+ B1B2+ cells behave as adult APs to maintain and repair DCT2/CNT1/CNT2/CD segments.

Potential renal stem/progenitor cells identified by in vivo lineage tracing.

Mammalian kidneys consist of more than 30 different types of cells. A challenging task is to identify and characterize the stem/progenitor subpopulations that establish the lineage relationships among these cellular elements during nephrogenesis in the embryonic and neonate kidneys and during tissue homeostasis and/or injury repair in the mature kidney. Moreover, the potential clinical utility of stem/progenitor cells holds promise for the development of new regenerative medicine approaches for the treatment of renal diseases. Stem cells are defined by unlimited self-renewal capacity and pluripotentiality. Progenitor cells have pluripotentiality but no or limited self-renewal potential. Cre-LoxP-based in vivo genetic lineage tracing is a powerful tool to identify stem/progenitor cells in their native environment. Hypothetically, this technique enables investigators to accurately track the progeny of a single cell or a group of cells. The Cre/LoxP system has been widely used to uncover the function of genes in various mammalian tissues and to identify stem/progenitor cells through in vivo lineage tracing analyses. In this review, we summarize the recent advances in the development and characterization of various Cre drivers and their use in identifying potential renal stem/progenitor cells in both developing and mature mouse kidneys.

Bola-Amphiphilic Glycodendrimers: New Carbohydrate-Mimicking Scaffolds to Target Carbohydrate-Binding Proteins.

Dendrimers are appealing scaffolds for creating carbohydrate mimics with unique multivalent cooperativity. We report here novel bola-amphiphilic glycodendrimers bearing mannose and glucose terminals, and a hydrophobic thioacetal core responsive to reactive oxygen species. The peculiar bola-amphiphilic feature enabled stronger binding to lectin compared to conventional amphiphiles. In addition, these dendrimers are able to target mannose receptors and glucose transporters expressed at the surface of cells, thus allowing effective and specific cellular uptake. This highlights their great promise for targeted delivery.

Depletion of NK Cells Improves Cognitive Function in the Alzheimer Disease Mouse Model.

Despite mounting evidence suggesting the involvement of the immune system in regulating brain function, the specific role of immune and inflammatory cells in neurodegenerative diseases remain poorly understood. In this study, we report that depletion of NK cells, a type of innate lymphocytes, alleviates neuroinflammation, stimulates neurogenesis, and improves cognitive function in a triple-transgenic Alzheimer disease (AD) mouse model. NK cells in the brains of triple-transgenic AD mouse model (3xTg-AD) mice exhibited an enhanced proinflammatory profile. Depletion of NK cells by anti-NK1.1 Abs drastically improved cognitive function of 3xTg-AD mice. NK cell depletion did not affect amyloid ß concentrations but enhanced neurogenesis and reduced neuroinflammation. Notably, in 3xTg-AD mice depleted of NK cells, microglia demonstrated a homeostatic-like morphology, decreased proliferative response and reduced expression of neurodestructive proinflammatory cytokines. Together, our results suggest a proinflammatory role for NK cells in 3xTg-AD mice and indicate that targeting NK cells might unlock novel strategies to combat AD.

Generation of Distal Renal Segments Involves a Unique Population of Aqp2 + Progenitor Cells.

BACKGROUND: Progenitor cells have clonogenicity, self-renewal, and multipotential capacity, and they can generate multiple types of cells during development. Evidence demonstrating the existence of such progenitor cells for renal distal segments is lacking. METHODS: To identify Aqp2 + progenitor (AP) cells, we performed in vivo lineage tracing using both constitutive ( Aqp2Cre RFP/+ ) and Tamoxifen-inducible ( Aqp2 ECE/+ RFP/+ , Aqp2 ECE/+ Brainbow/+ , and Aqp2 ECE/+ Brainbow/Brainbow ) mouse models. Aqp2Cre RFP/+ mice were analyzed from E14.5 to adult stage. The inducible models were induced at P1 and examined at P3 and P42, respectively. Multiple segment- or cell-specific markers were used for high-resolution immunofluorescence confocal microscopy analyses to identify the cell types derived from Aqp2 + cells. RESULTS: Both Aqp2Cre and Aqp2 ECE/+ faithfully indicate the activation of the endogenous Aqp2 promoter for lineage tracing. A subset of Aqp2 + cells behaves as potential AP. Aqp2Cre -based lineage tracing revealed that embryonic APs generate five types of cells, which form the late distal convoluted tubule (DCT2), connecting tubule segments 1 and 2 (CNT1 and CNT2, respectively), and collecting ducts (CDs). The α - and ß -intercalated cells were apparently derived from embryonic AP in a stepwise manner. Aqp2 ECE/+ -based lineage tracing identified cells coexpressing Aqp2 and V-ATPase subunits B1 and B2 as the potential AP. Neonate APs generate daughter cells either inheriting their property (self-renewal) or evolving into various DCT2, CNT, or CD cells (multipotentiality), forming single cell-derived multiple-cell clones (clonogenicity) during development. CONCLUSION: Our study demonstrates that unique Aqp2 + B1B2 + cells are the potential APs to generate DCT2, CNT, CNT2, and CD segments.

Loss of Histone H3 K79 Methyltransferase Dot1l Facilitates Kidney Fibrosis by Upregulating Endothelin 1 through Histone Deacetylase 2.

BACKGROUND: The progression rate of CKD varies substantially among patients. The genetic and epigenetic contributions that modify how individual patients respond to kidney injury are largely unknown. Emerging evidence has suggested that histone H3 K79 methyltransferase Dot1l has an antifibrotic effect by repressing Edn1, which encodes endothelin 1 in the connecting tubule/collecting duct. METHODS: To determine if deletion of the Dot1l gene is a genetic and epigenetic risk factor through regulating Edn1, we studied four groups of mice: wild-type mice, connecting tubule/collecting duct-specific Dot1l conditional knockout mice (Dot1lAC ), Dot1l and Edn1 double-knockout mice (DEAC ), and Edn1 connecting tubule/collecting duct-specific conditional knockout mice (Edn1AC ), under three experimental conditions (streptozotocin-induced diabetes, during normal aging, and after unilateral ureteral obstruction). We used several approaches (colocalization, glutathione S-transferase pulldown, coimmunoprecipitation, yeast two-hybrid, gel shift, and chromatin immunoprecipitation assays) to identify and confirm interaction of Dot1a (the major Dot1l splicing variant in the mouse kidney) with histone deacetylase 2 (HDAC2), as well as the function of the Dot1a-HDAC2 complex in regulating Edn1 transcription. RESULTS: In each case, Dot1lAC mice developed more pronounced kidney fibrosis and kidney malfunction compared with wild-type mice. These Dot1lAC phenotypes were ameliorated in the double-knockout DEAC mice. The interaction between Dot1a and HDAC2 prevents the Dot1a-HDAC2 complex from association with DNA, providing a counterbalancing mechanism governing Edn1 transcription by modulating H3 K79 dimethylation and H3 acetylation at the Edn1 promoter. CONCLUSIONS: Our study confirms Dot1l to be a genetic and epigenetic modifier of kidney fibrosis, reveals a new mechanism regulating Edn1 transcription by Dot1a and HDAC2, and reinforces endothelin 1 as a therapeutic target of kidney fibrosis.

[A preliminary study on the diagnostic value of infrared thermography in children with idiopathic thrombocytopenic purpura].

Idiopathic thrombocytopenic purpura (ITP) is a common bloody disease with a high incidence in children, but its diagnostic method is exclusive diagnosis, and the existing detection techniques are mostly invasive, which may cause secondary injury to patients and also may increase the risk of disease. In order to make up for the lack of the detection method, this study made a preliminary exploration on the diagnosis of children's ITP from the perspective of infrared thermography. In this study, a total of 11 healthy children and 22 ITP children's frontal infrared thermal images were collected, and the pattern characteristic (PFD), average temperature (Troi) and maximum temperature (MAX) characteristics of 7 target areas were extracted. The weighted PFD parameters were correlated with the platelet count commonly used in clinical diagnosis, and the sensitivity and specificity of the weighted PFD parameters for children's ITP were calculated through the receiver operating characteristic curve (ROC). The final results showed that the difference of the weighted PFD parameters between healthy children and ITP children was statistically significant, and the parameters negatively correlated with platelet count. Under the ROC curve, the area under the curve (AUC) of this parameter is as high as 92.1%. Based on the research results of this paper, infrared thermography can clearly show the difference between ITP children and healthy children. It is hoped that the methods proposed in this paper can non-invasively and objectively describe the characteristics of ITP infrared thermal imaging of children, and provide a new ideas for ITP diagnosis.

Aquaporin-1 attenuates macrophage-mediated inflammatory responses by inhibiting p38 mitogen-activated protein kinase activation in lipopolysaccharide-induced acute kidney injury.

OBJECTIVE: This study was designed to investigate the role of AQP1 in the development of LPS-induced AKI and its potential regulatory mechanisms in the inflammatory responses of macrophages. METHODS: Male Wistar rats were injected intraperitoneally with LPS, and biochemical and histological renal damage was assessed. The levels of inflammatory mediators, macrophage markers and AQP1 in blood and kidney tissues were assessed by ELISA. RTPCR was used to assess changes in the relative levels of AQP1 mRNA induced by LPS. Western blot and immunofluorescence analyses were performed to assay the activation of the p38 MAPK and NF-κB pathways, respectively. The same detection methods were used in vitro to determine the regulatory mechanisms underlying AQP1 function. RESULTS: AQP1 mRNA levels were dramatically decreased in AKI rats following the increased expression of inflammatory factors. In vitro experiments demonstrated that silencing the AQP1 gene increased inflammatory mediator secretion, altered the classical activation of macrophages, greatly enhanced the phosphorylation of p38 and accelerated the translocation of NF-κB. Furthermore, these results were blocked by doramapimod, a p38 inhibitor. Therefore, these effects were mediated by the increased phosphorylation of p38 MAPK. CONCLUSION: Our results suggest that altered AQP1 expression may be associated with the development of inflammation in AKI. AQP1 plays a protective role in modulating acute renal injury and can attenuate macrophage-mediated inflammatory responses by downregulating p38 MAPK activity in LPS-induced RAW264.7 cells. The pharmacological targeting of AQP1-mediated p38 MAPK signalling may provide a novel treatment approach for AKI.

Visible-light-mediated difunctionalization of vinylcyclopropanes for the synthesis of 1-sulfonylmethyl-3,4-dihydronaphthalenes.

An efficient method for visible-light-mediated sulfonylation/arylation of the C-C σ-bond in vinylcyclopropanes with sulfonyl chlorides to synthesize 1-sulfonylmethyl-substituted 3,4-dihydronaphalenes has been developed. A radical-type pathway has been proved in this transformation. This difunctionalization procedure shows a series of advantages, such as the use of commercially and easily available sulfonyl chlorides, mild conditions, and eco-friendly energy.

A class II KNOX gene, KNOX4, controls seed physical dormancy.

Physical dormancy of seed is an adaptive trait that widely exists in higher plants. This kind of dormancy is caused by a water-impermeable layer that blocks water and oxygen from the surrounding environment and keeps embryos in a viable status for a long time. Most of the work on hardseededness has focused on morphological structure and phenolic content of seed coat. The molecular mechanism underlying physical dormancy remains largely elusive. By screening a large number of Tnt1 retrotransposon-tagged Medicago truncatula lines, we identified nondormant seed mutants from this model legume species. Unlike wild-type hard seeds exhibiting physical dormancy, the mature mutant seeds imbibed water quickly and germinated easily, without the need for scarification. Microscopic observations of cross sections showed that the mutant phenotype was caused by a dysfunctional palisade cuticle layer in the seed coat. Chemical analysis found differences in lipid monomer composition between the wild-type and mutant seed coats. Genetic and molecular analyses revealed that a class II KNOTTED-like homeobox (KNOXII) gene, KNOX4, was responsible for the loss of physical dormancy in the seeds of the mutants. Microarray and chromatin immunoprecipitation analyses identified CYP86A, a gene associated with cutin biosynthesis, as one of the downstream target genes of KNOX4 This study elucidated a novel molecular mechanism of physical dormancy and revealed a new role of class II KNOX genes. Furthermore, KNOX4-like genes exist widely in seed plants but are lacking in nonseed species, indicating that KNOX4 may have diverged from the other KNOXII genes during the evolution of seed plants.

Highly tamoxifen-inducible principal cell-specific Cre mice with complete fidelity in cell specificity and no leakiness.

An ideal inducible system should be cell specific and have absolutely no background recombination without induction (i.e., no leakiness), a high recombination rate after induction, and complete fidelity in cell specificity (i.e., restricted recombination exclusively in cells where the driver gene is expressed). However, such an ideal mouse model remains unavailable for collecting duct research. Here, we report a mouse model that meets these criteria. In this model, a cassette expressing ERT2CreERT2 ( ECE) is inserted at the ATG of the endogenous Aqp2 locus to disrupt Aqp2 function and to express ECE under the control of the Aqp2 promoter. The resulting allele is named Aqp2ECE. There was no indication of a significant impact of disruption of a copy of Aqp2 on renal function and blood pressure control in adult Aqp2ECE/+ heterozygotes. Without tamoxifen, Aqp2ECE did not activate a Cre-dependent red fluorescence protein (RFP) reporter in adult kidneys. A single injection of tamoxifen (2 mg) to adult mice enabled Aqp2ECE to induce robust RFP expression in the whole kidney 24 h postinjection, with the highest recombination efficiency of 95% in the inner medulla. All RFP-labeled cells expressed principal cell markers (Aqp2 and Aqp3), but not intercalated cell markers (V-ATPase B1B2, and carbonic anhydrase II). Hence, Aqp2ECE confers principal cell-specific tamoxifen-inducible recombination with absolutely no leakiness, high inducibility, and complete fidelity in cell specificity, which should be an important tool for temporospatial control of target genes in the principal cells and for Aqp2+ lineage tracing in adult mice.

Arabidopsis CALCIUM-DEPENDENT PROTEIN KINASE8 and CATALASE3 Function in Abscisic Acid-Mediated Signaling and H2O2 Homeostasis in Stomatal Guard Cells under Drought Stress.

Drought is a major threat to plant growth and crop productivity. Calcium-dependent protein kinases (CDPKs, CPKs) are believed to play important roles in plant responses to drought stress. Here, we report that Arabidopsis thaliana CPK8 functions in abscisic acid (ABA)- and Ca(2+)-mediated plant responses to drought stress. The cpk8 mutant was more sensitive to drought stress than wild-type plants, while the transgenic plants overexpressing CPK8 showed enhanced tolerance to drought stress compared with wild-type plants. ABA-, H2O2-, and Ca(2+)-induced stomatal closing were impaired in cpk8 mutants. Arabidopsis CATALASE3 (CAT3) was identified as a CPK8-interacting protein, confirmed by yeast two-hybrid, coimmunoprecipitation, and bimolecular fluorescence complementation assays. CPK8 can phosphorylate CAT3 at Ser-261 and regulate its activity. Both cpk8 and cat3 plants showed lower catalase activity and higher accumulation of H2O2 compared with wild-type plants. The cat3 mutant displayed a similar drought stress-sensitive phenotype as cpk8 mutant. Moreover, ABA and Ca(2+) inhibition of inward K(+) currents were diminished in guard cells of cpk8 and cat3 mutants. Together, these results demonstrated that CPK8 functions in ABA-mediated stomatal regulation in responses to drought stress through regulation of CAT3 activity.

Gold-catalyzed C5-alkylation of indolines and sequential oxidative aromatization: access to C5-functionalized indoles.

A novel protocol for the synthesis of C5-alkylated indole derivatives via a gold-catalyzed reaction of indolines with diazo compounds and subsequent oxidative aromatization has been developed. C-H bond functionalization selectively occurs at the C5-position of indolines without a directing group. The experimental operation is simple and the whole process can be manipulated in one-pot.