足细胞发育异常及相关肾脏疾病研究进展

足细胞是肾小球滤过屏障的重要组成部分,其数量减少或功能障碍将导致肾小球滤过功能损伤和相关肾脏疾病的发生。足细胞为不可再生性细胞,其数量和功能在一定程度上取决于其正常发育。已发表的文献和本实验室的研究工作表明,遗传或不良宫内环境等原因所致的足细胞发育不良,可能导致成年后肾小球滤过功能障碍,并成为某些胎源性肾脏疾病发生或易感的病因之一,而表观遗传学机制可能参与介导足细胞发育过程中某些关键基因的表达异常。本文对足细胞结构功能和正常发育、足细胞发育异常的病因和机制、以及足细胞发育异常所致的肾脏疾病等几方面进行综述,以期对发育源性足细胞相关肾脏疾病的诊断与治疗提供借鉴与参考。     

Safety of co-administration of herbal and conventional medicines on liver and kidney function in stroke patients: A single-center retrospective study

BackgroundAlthough herbal medicines (HMs) are widely used worldwide, information concerning their interactions with conventional medicines (CMs) is sparse. In particular, stroke affects a high proportion of elderly people with impaired hepatic and renal function. Stroke is often accompanied by various complications and is commonly treated via the co-administration of HMs and CMs in Asia.PurposeWe aimed to investigate the effects of co-administration of HMs and CMs on liver and kidney function in patients with stroke. We estimated the prevalence of drug-induced liver injury (DILI) or herb-induced liver injury (HILI) and drug-induced acute kidney injury (DIAKI) or herb-induced acute kidney injury (HIAKI) in patients co-administered HMs and CMs.Study designThis was a retrospective study that reviewed the electronic medical records of 401 patients with stroke in a single hospital.MethodsThe prevalence of DILI or HILI and types of liver injury was examined according to abnormal increases in liver tests. The probable causality between drug or herb administration and liver injury was assessed using the Roussel Uclaf Causality Assessment Method. In addition, the prevalence of DIAKI or HIAKI was estimated using the Kidney Disease Improving Global Outcomes acute kidney injury stage criteria and related medical records.ResultsOut of a total of 401 patients, only four (1.0%) developed liver injury. Two cases of DILI (0.5%) and two cases of HILI (0.5%) were reported. Moxifloxacin and ebastine were the CMs that caused hepatotoxicity. Chungpyesagan-tang and Yeoldahanso-tang were the HMs that caused liver toxicity. Even in cases showing severe liver damage, alkaline phosphatase levels remained less than five times the normal value, and liver function test values recovered within 14 days. There were no cases of DIAKI or HIAKI in this cohort.ConclusionThese results suggest that if appropriately prescribed by experts, the co-administration of CMs and HMs is safe and does not adversely affect liver and kidney function in patients with stroke. To support these results, further large-scale multicenter prospective studies and toxicological studies based on the interaction between HMs and CMs are warranted.     

Emerging roles for lymphatics in acute kidney injury: Beneficial or maleficent?

Acute kidney injury, a sudden decline in renal filtration, is a surprisingly common pathology resulting from ischemic events, local or systemic infection, or drug-induced toxicity in the kidney. Unchecked, acute kidney injury can progress to renal failure and even recovered acute kidney injury patients are at an increased risk for developing future chronic kidney disease. The initial extent of inflammation, the specific immune response, and how well inflammation resolves are likely determinants in acute kidney injury-to-chronic kidney disease progression. Lymphatic vessels and their roles in fluid, solute, antigen, and immune cell transport make them likely to have a role in the acute kidney injury response. Lymphatics have proven to be an attractive target in regulating inflammation and immunomodulation in other pathologies: might these strategies be employed in acute kidney injury? Acute kidney injury studies have identified elevated levels of lymphangiogenic ligands following acute kidney injury, with an expansion of the lymphatics in several models post-injury. Manipulating the lymphatics in acute kidney injury, by augmenting or inhibiting their growth or through targeting lymphatic-immune interactions, has met with a range of positive, negative, and sometimes inconclusive results. This minireview briefly summarizes the findings of lymphatic changes and lymphatic roles in the inflammatory response in the kidney following acute kidney injury to discuss whether renal lymphatics are a beneficial, maleficent, or a passive contributor to acute kidney injury recovery.     

Phosphoproteomic analysis of cells treated with longevity-related autophagy inducers

Macroautophagy is a self-cannibalistic process that enables cells to adapt to various stresses and maintain energy homeostasis. Additionally, autophagy is an important route for turnover of misfolded proteins and damaged organelles, with important implications in cancer, neurodegenerative diseases and aging. Resveratrol and spermidine are able to induce autophagy by affecting deacetylases and acetylases, respectively, and have been found to extend the life-span of model organisms. With the aim to reveal the signaling networks involved in this drug-induced autophagic response, we quantified resveratrol and spermidine-induced changes in the phosphoproteome using SILAC and mass spectrometry. The data were subsequently analyzed using the NetworKIN algorithm to extract key features of the autophagy-responsive kinase-substrate network. We found that two distinct sequence motifs were highly responsive to resveratrol and spermidine and that key proteins modulating the acetylation, phosphorylation, methylation and ubiquitination status were affected by changes in phosphorylation during the autophagic response. Essential parts of the apoptotic signaling network were subjected to post-translational modifications during the drug-induced autophagy response, suggesting potential crosstalk and balancing between autophagy and apoptosis. Additionally, we predicted cellular signaling networks affected by resveratrol and spermidine using a computational framework. Altogether, these results point to a profound crosstalk between distinct networks of post-translational modifications and provide a resource for future analysis of autophagy and cell death.     

Ion channels and transporters in the development of drug resistance in cancer cells

Multi-drug resistance (MDR) to chemotherapy is the major challenge in the treatment of cancer. MDR can develop by numerous mechanisms including decreased drug uptake, increased drug efflux and the failure to undergo drug-induced apoptosis. Evasion of drug-induced apoptosis through modulation of ion transporters is the main focus of this paper and we demonstrate how pro-apoptotic ion channels are downregulated, while anti-apoptotic ion transporters are upregulated in MDR. We also discuss whether upregulation of ion transport proteins that are important for proliferation contribute to MDR. Finally, we discuss the possibility that the development of MDR involves sequential and localized upregulation of ion channels involved in proliferation and migration and a concomitant global and persistent downregulation of ion channels involved in apoptosis.     

Efficacy of using litonit in the combined therapy of infectious-inflammatory kidney lesions in alcoholism

The results of 250 experiments suggest the advisability of using a new antialcoholic metabolite drug, litonit, in combined therapy of infectious-inflammatory kidney disorders occurring in alcoholism. The course of litonit injections does not only increase considerably the content of oxidized and reduced nicotinamide coenzymes, but also normalizes the number of IgA, IgG and IgM. Certain drug-induced functional and immunological shifts are now believed to indicate the increase in the functional renal capacity and enhanced kidney resistance to inflammation.     

Endoplasmic reticulum stress and kidney dysfunction

Chronic kidney disease (CKD) affects millions of persons worldwide and constitutes a major public health problem. Therefore, understanding the molecular basis of CKD is a key challenge for the development of preventive and therapeutic strategies. A major contributor to chronic histological damage associated with CKD is acute kidney injury (AKI). At the cellular level, kidney injuries are associated with microenvironmental alterations, forcing cells to activate adaptive biological processes that eliminate the stressor and generate alarm signals. These signalling pathways actively participate in tissue remodelling by promoting inflammation and fibrogenesis, ultimately leading to CKD. Many stresses that are encountered upon kidney injury are prone to trigger endoplasmic reticulum (ER) stress. In the kidney, ER stress both participates in acute and chronic histological damages, but also promotes cellular adaptation and nephroprotection. In this review, we will discuss the implication of ER stress in the pathophysiology of AKI and CKD progression, and we will give a critical analysis of the current experimental and clinical evidence that support ER stress as a mediator of kidney damage.     

Activated renal macrophages are markers of disease onset and disease remission in lupus nephritis

Costimulatory blockade with CTLA4Ig and anti-CD40L along with a single dose of cyclophosphamide induces remission of systemic lupus erythematosus nephritis in NZB/W F(1) mice. To understand the mechanisms for remission and for impending relapse, we examined the expression profiles of 61 inflammatory molecules in the perfused kidneys of treated mice and untreated mice at different stages of disease. Further studies using flow cytometry and immunohistochemistry allowed us to determine the cellular origins of several key markers. We show that only a limited set of inflammatory mediators is expressed in the kidney following glomerular immune complex deposition but before the onset of proteinuria. Formation of a lymphoid aggregate in the renal pelvis precedes the invasion of the kidney by inflammatory cells. Regulatory molecules are expressed early in the disease process and during remission but do not prevent the inevitable progression of active inflammation. Onset of proliferative glomerulonephritis and proteinuria is associated with activation of the renal endothelium, expression of chemokines that mediate glomerular cell infiltration, and infiltration by activated dendritic cells and macrophages that migrate to different topographical areas of the kidney but express a similar profile of inflammatory cytokines. Increasing interstitial infiltration by macrophages and progressive tubular damage, manifested by production of lipocalin-2, occur later in the disease process. Studies of treated mice identify a type II (M2b)-activated macrophage as a marker of remission induction and impending relapse and suggest that therapy for systemic lupus erythematosus nephritis should include strategies that prevent both activation of monocytes and their migration to the kidney.     

Comparison of the course of biomarker changes and kidney injury in a rat model of drug-induced acute kidney injury

Objective: To aid in evaluating the performance of biomarkers, we measured kidney injury biomarkers in rat models of drug-induced acute kidney injury. Methods and results: Rats were treated with site-specific nephrotoxins, puromycin, gentamicin, cisplatin, or 2-bromoethylamine. Fifteen biomarkers (β-2-microglobulin, calbindin, clusterin, cystatin-C, KIM-1, GST-α, GST-μ, NGAL, osteopontin, EGF, TIMP-1, VEGF, albumin, RPA-1, and urinary total protein) were examined in comparison with BUN, serum creatinine, and NAG. Some biomarkers, which were different depending in each nephrotoxin, showed ability to detect the prodromal stage of drug-induced kidney injury. Characteristic changing patterns of biomarkers were also found depending on the specific lesion site in the kidney. Conclusion: These data suggested that establishment of a suitable biomarker panel would facilitate detection of site-specific kidney injury with high sensitivity.     

The application of renal cells in culture in studying drug-induced nephrotoxicity

Summary Kidney cells in culture represent one of many in vitro approaches for studying drug-induced nephrotoxicity. Pontential advantages of cell culture systems compared to more traditional in vitro models include a) the ability to examine direct effects at the cellular level, b) extended viability, c) ability for long-term storage, and d) capabilities for automation. Primary cultures of kidney tubules as well as cell lines of kidney origin are currently under evaluation as model systems for the assement of nephrotoxicity. The application of two renal cell systems, rabbit primary proximal tubule cultures and the pig kidney cell line, LLC-PK₁, in studying mechanisms of drug-induced nephrotoxicity is described in this communication. Potentially valuable insights intothe renal pathogenesis associated with the antitumor agent, cis-diamminedichloroplatium II, and the aminoglycoside antibiotic, gentamicin, have been obtained utilizing these renal cell models. Challenges in renal cll culture involve the characterization and mainternance of differentiated properties and the development of technologies to a) study bidirectional transport-toxicity of drugs, and b) provide a dynamic vs. static fluid environment as in vivo. Despite these unique challeges as well as the universal challeges involved in extrapolating any in vitro data to the in vivo situation, recent studies indicate that renal cells in culture are useful in the elucidation of mechanisms of drug-induced renal injury. This paper was presented at a Symposium on the Physiology and Toxicology of the Kidney In Vitro co-sponsored by The Society of Toxicology (SOT) and the Tissue Culture Association held at the 27th annual meeting of the SOT in Dallas, Texas in 1988.     

青藏高原和内蒙古高原典型草地植物叶片肾型和哑铃型气孔器气孔特征及其与环境的关系

该研究利用植物制片技术,以中国青藏高原和内蒙古高原典型草地常见种或优势种植物的叶片为研究对象,通过比较分析叶片哑铃型气孔器和肾型气孔器的特征及其与环境因子的关系,揭示植物叶片两类气孔器对环境因子的响应策略。结果表明:(1)叶片哑铃型气孔器气孔指标的变异系数小于肾型气孔器。(2)叶片哑铃型气孔器气孔指标与环境气候指标的关系弱于肾型气孔器。(3)叶片哑铃型气孔器气孔特征与环境关系在叶片上下表面之间存在显著差异,而肾型气孔器气孔特征与环境因子的关系在叶片上下表面之间无显著差异。(4)叶片哑铃型气孔器的气孔特征与降水关系密切,而肾型气孔器气孔特征与温度关系密切。(5)同一种气孔器的气孔特征在两个地区(青藏高原和内蒙古高原)间存在显著差异。研究认为,肾型气孔器和哑铃型气孔器的气孔特征及其与环境之间的关系存在差异,在分析气孔特征时有必要将肾形与哑铃形保卫细胞形成的气孔器加以区分,该研究结果有助于进一步理解中国草地植物叶气孔特征对气候变化的响应与适应策略。     

Comparison of the course of biomarker changes and kidney injury in a rat model of drug-induced acute kidney injury

Objective: To aid in evaluating the performance of biomarkers, we measured kidney injury biomarkers in rat models of drug-induced acute kidney injury.

Methods and results: Rats were treated with site-specific nephrotoxins, puromycin, gentamicin, cisplatin, or 2-bromoethylamine. Fifteen biomarkers (β-2-microglobulin, calbindin, clusterin, cystatin-C, KIM-1, GST-α, GST-μ, NGAL, osteopontin, EGF, TIMP-1, VEGF, albumin, RPA-1, and urinary total protein) were examined in comparison with BUN, serum creatinine, and NAG. Some biomarkers, which were different depending in each nephrotoxin, showed ability to detect the prodromal stage of drug-induced kidney injury. Characteristic changing patterns of biomarkers were also found depending on the specific lesion site in the kidney.

Conclusion: These data suggested that establishment of a suitable biomarker panel would facilitate detection of site-specific kidney injury with high sensitivity.     

Chemoproteomic approaches to drug target identification and drug profiling

Chemoproteomics represents a new research discipline at the interface of medicinal chemistry, biochemistry, and cell biology focused on studying the molecular mechanisms of action of drugs and other bioactive small molecules. Research strategies frequently combine phenotypic screening with subsequent target identification, and aim at a proteome-wide characterization of drug-induced changes in cellular protein expression and post-translational modifications. In recent years quantitative mass spectrometry has taken center stage in many of these approaches. This review describes experimental strategies in current chemical proteomics research, discusses recent examples of successful applications, and highlights areas in drug discovery where chemical proteomics-based assays using native endogenous proteins are expected to have substantial impact.     

Toward high-content screening of mitochondrial morphology and membrane potential in living cells

Mitochondria are double membrane organelles involved in various key cellular processes. Governed by dedicated protein machinery, mitochondria move and continuously fuse and divide. These “mitochondrial dynamics” are bi-directionally linked to mitochondrial and cell functional state in space and time. Due to the action of the electron transport chain (ETC), the mitochondrial inner membrane displays a inside-negative membrane potential (Δψ). The latter is considered a functional readout of mitochondrial “health” and required to sustain normal mitochondrial ATP production and mitochondrial fusion. During the last decade, live-cell microscopy strategies were developed for simultaneous quantification of Δψ and mitochondrial morphology. This revealed that ETC dysfunction, changes in Δψ and aberrations in mitochondrial structure often occur in parallel, suggesting they are linked potential targets for therapeutic intervention. Here we discuss how combining high-content and high-throughput strategies can be used for analysis of genetic and/or drug-induced effects at the level of individual organelles, cells and cell populations.This article is part of a Directed Issue entitled: Energy Metabolism Disorders and Therapies.     

Renal stem cell reprogramming: Prospects in regenerative medicine

Stem cell therapy is a promising future enterprise for renal replacement in patients with acute and chronic kidney disease, conditions which affect millions worldwide and currently require patients to undergo lifelong medical treatments through dialysis and/or organ transplant. Reprogramming differentiated renal cells harvested from the patient back into a pluripotent state would decrease the risk of tissue rejection and provide a virtually unlimited supply of cells for regenerative medicine treatments, making it an exciting area of current research in nephrology. Among the major hurdles that need to be overcome before stem cell therapy for the kidney can be applied in a clinical setting are ensuring the fidelity and relative safety of the reprogrammed cells, as well as achieving feasible efficiency in the reprogramming processes that are utilized. Further, improved knowledge about the genetic control of renal lineage development is vital to identifying predictable and efficient reprogramming approaches, such as the expression of key modulators or the regulation of geneactivity through small molecule mimetics. Here, we discuss several recent advances in induced pluripotent stem cell technologies. We also explore strategies that have been successful in renal progenitor generation, and explore what these methods might mean for the development of cell-based regenerative therapies for kidney disease.     

Collective Epithelial Migration Drives Kidney Repair after Acute Injury

Acute kidney injury (AKI) is a common and significant medical problem. Despite the kidney’s remarkable regenerative capacity, the mortality rate for the AKI patients is high. Thus, there remains a need to better understand the cellular mechanisms of nephron repair in order to develop new strategies that would enhance the intrinsic ability of kidney tissue to regenerate. Here, using a novel, laser ablation-based, zebrafish model of AKI, we show that collective migration of kidney epithelial cells is a primary early response to acute injury. We also show that cell proliferation is a late response of regenerating kidney epithelia that follows cell migration during kidney repair. We propose a computational model that predicts this temporal relationship and suggests that cell stretch is a mechanical link between migration and proliferation, and present experimental evidence in support of this hypothesis. Overall, this study advances our understanding of kidney repair mechanisms by highlighting a primary role for collective cell migration, laying a foundation for new approaches to treatment of AKI.     

Role of nanotopography in the development of tissue engineered 3D organs and tissues using mesenchymal stem cells

Recent regenerative medicine and tissue engineering strategies(using cells, scaffolds, medical devices and gene therapy) have led to fascinating progress of translation of basic research towards clinical applications. In the past decade, great deal of research has focused on developing various three dimensional(3D) organs, such as bone, skin, liver, kidney and ear,using such strategies in order to replace or regenerate damaged organs for the purpose of maintaining or restoring organs’ functions that may have been lost due to aging, accident or disease. The surface properties of a material or a device are key aspects in determining the success of the implant in biomedicine, as the majority of biological reactions in human body occur on surfaces or interfaces. Furthermore, it has been established in the literature that cell adhesion and proliferation are, to a great extent, influenced by the micro- and nanosurface characteristics of biomaterials and devices. In addition, it has been shown that the functions of stem cells, mesenchymal stem cells in particular, could be regulated through physical interaction with specific nanotopographical cues. Therefore, guided stem cell proliferation, differentiation and function are of great importance in the regeneration of 3D tissues and organs using tissue engineering strategies. This review will provide an update on the impact of nanotopography on mesenchymal stem cells for the purpose of developing laboratory-based 3D organs and tissues, as well as the most recent research and case studies on this topic.     

Uteroplacental insufficiency increases apoptosis and alters p53 gene methylation in the full-term IUGR rat kidney

Uteroplacental insufficiency causes intrauterine growth retardation (IUGR), which is associated with adult onset diseases such as hypertension. Previous studies demonstrate that growth retardation in humans and rats decreases glomeruli number; however, the molecular mechanisms responsible for this reduction are unknown. Apoptosis plays a key role in renal organogenesis. We therefore hypothesized that the in utero deprivation associated with uteroplacental insufficiency decreases glomeruli, increases apoptosis, and alters the mRNA levels of key apoptosis-related proteins in full-term IUGR kidneys. To prove this hypothesis, we induced asymmetric IUGR through bilateral uterine artery ligation of the pregnant rat. We found that uteroplacental insufficiency significantly reduced glomeruli number while increasing TUNEL staining and caspase-3 activity in the IUGR kidney. A significant decrease in Bcl-2 mRNA and a significant increase in Bax and p53 mRNA further characterized the IUGR kidney. Because altered p53 CpG methylation affects p53 expression, we analyzed p53 promoter CpG methylation using methylation-sensitive restriction enzymes and real-time PCR. Uteroplacental insufficiency specifically decreased CpG methylation of the renal p53 BstU I site promoter without affecting the Hha I or the Aci I sites. Uteroplacental insufficiency also induced a relative hypomethylation from exon 5 to exon 8, which was associated with deceased mRNA levels of DNMT1. We conclude that uteroplacental insufficiency alters p53 DNA CpG methylation, affects mRNA levels of key apoptosis-related proteins, increases renal apoptosis, and reduces glomeruli number in the IUGR kidney. We speculate that these changes represent mechanisms that contribute to the fetal origins of adult disease.     

A continental approach to jaguar extirpation: A tradeoff between anthropic and intrinsic causes

Human impacts are blamed for range contraction in several animal species worldwide. Remarkably, carnivores and particularly top predators are threatened by humans despite their key role in maintaining ecosystem balance and functions. Conservation strategies to allow human-carnivore coexistence are urgently needed. These strategies must be built on evidence and driven by knowledge of population risk at a broad scale. However, knowledge on wide distributed species is often based on regional expert opinions in which uncertainty is not quantifiable, making data incomparable across regions. Here we develop a method to assess the endangerment status of a species based on its range contractions and the main threats using the jaguar Panthera onca as model. The use of GLM with the main intrinsic and extrinsic drivers of jaguar extinction allowed us to assess the endangerment status at continental and population scale. We found this method to be a valuable tool to obtain a broad picture of human-induced endangerment in animal species. Intrinsic traits (summarized in the demographic contraction theory) and anthropic traits (based on agriculture, cattle and human densities) explained jaguar extinction highlighting the particular importance of livestock activity. Our results suggest that livestock ranching has a pervasive effect on the species likely due to habitat loss combined with retaliatory hunting. We highlight the need to rethink policies, practice and law enforcement in relation to livestock and suggest the development of action plans based in local evidence in those countries where endangered populations have been detected. We also recommend involving and encouraging land owners and private companies in the conservation of private lands that comprise much of the endangered jaguar range.