Role of Krüppel-like factor-2 in kidney disease

Exploring the Functionality of the Krüppel-like Factors in Kidney Development, Metabolism, and Diseases

The kidneys contribute to the overall health of an organism by maintaining systemic homeostasis. This process involves various biological mechanisms, in which the Krüppel-like factors (KLFs), a family of transcription factors, are essential for regulating development, differentiation, proliferation, and cellular apoptosis. They also play a role in the metabolic regulation of essential nutrients, such as glucose and lipids. The dysregulation of these transcription factors is associated with the development of various pathologies, which can ultimately lead to renal fibrosis, severely compromising kidney function. In this context, the present article provides a comprehensive review of the existing literature, offering an enriching analysis of the findings related to the role of KLFs in nephrology, while also highlighting their potential therapeutic role in the treatment of renal diseases.

Unveiling the role of long non-coding RNA MALAT1: a comprehensive review on myocardial infarction

Myocardial infarction (MI) stands at top global causes of death in developed countries, owing mostly to atherosclerotic plaque growth and endothelial injury-induced reduction in coronary blood flow. While early reperfusion techniques have improved outcomes, long-term treatment continues to be difficult. The function of lncRNAs extends to regulating gene expression in various conditions, both physiological and pathological, such as cardiovascular diseases. The objective of this research is to extensively evaluate the significance of the lncRNA called Metastasis associated lung adenocarcinoma transcript 1 (MALAT1) in the development and management of MI. According to research, MALAT1 is implicated in processes such as autophagy, apoptosis, cell proliferation, and inflammation in the cardiovascular system. This investigation examines recent research examining the effects of MALAT1 on heart function and its potential as a mean of diagnosis and treatment for post- MI complications and ischemic reperfusion injury.

Crosstalk among podocytes, glomerular endothelial cells and mesangial cells in diabetic kidney disease: an updated review

Diabetic kidney disease (DKD) is a long-term and serious complication of diabetes that affects millions of people worldwide. It is characterized by proteinuria, glomerular damage, and renal fibrosis, leading to end-stage renal disease, and the pathogenesis is complex and involves multiple cellular and molecular mechanisms. Among three kinds of intraglomerular cells including podocytes, glomerular endothelial cells (GECs) and mesangial cells (MCs), the alterations in one cell type can produce changes in the others. The cell-to-cell crosstalk plays a crucial role in maintaining the glomerular filtration barrier (GFB) and homeostasis. In this review, we summarized the recent advances in understanding the pathological changes and interactions of these three types of cells in DKD and then focused on the signaling pathways and factors that mediate the crosstalk, such as angiopoietins, vascular endothelial growth factors, transforming growth factor-β, Krüppel-like factors, retinoic acid receptor response protein 1 and exosomes, etc. Furthermore, we also simply introduce the application of the latest technologies in studying cell interactions within glomerular cells and new promising mediators for cell crosstalk in DKD. In conclusion, this review provides a comprehensive and updated overview of the glomerular crosstalk in DKD and highlights its importance for the development of novel intervention approaches.

Tissue-Resident Memory T Cells in Allergy

Tissue-resident memory T (TRM) cells constitute a distinct subset within the memory T cell population, serving as the vanguard against invading pathogens and antigens in peripheral non-lymphoid tissues, including the respiratory tract, intestines, and skin. Notably, TRM cells adapt to the specific microenvironment of each tissue, predominantly maintaining a sessile state with distinctive phenotypic and functional attributes. Their role is to ensure continuous immunological surveillance and protection. Recent findings have highlighted the pivotal contribution of TRM cells to the modulation of adaptive immune responses in allergic disorders such as allergic rhinitis, asthma, and dermatitis. A comprehensive understanding of the involvement of TRM cells in allergic diseases bears profound implications for allergy prevention and treatment. This review comprehensively explores the phenotypic characteristics, developmental mechanisms, and functional roles of TRM cells, focusing on their intricate relationship with allergic diseases.

Participation of Krüppel-like Factors in Atherogenesis

Atherosclerosis is an important problem in modern medicine, the keys to understanding many aspects of which are still not available to clinicians. Atherosclerosis develops as a result of a complex chain of events in which many cells of the vascular wall and peripheral blood flow are involved. Endothelial cells, which line the vascular wall in a monolayer, play an important role in vascular biology. A growing body of evidence strengthens the understanding of the multifaceted functions of endothelial cells, which not only organize the barrier between blood flow and tissues but also act as regulators of hemodynamics and play an important role in regulating the function of other cells in the vascular wall. Krüppel-like factors (KLFs) perform several biological functions in various cells of the vascular wall. The large family of KLFs in humans includes 18 members, among which KLF2 and KLF4 are at the crossroads between endothelial cell mechanobiology and immunometabolism, which play important roles in both the normal vascular wall and atherosclerosis.

Krüppel-like factor 2a (KLF2A) suppresses GCRV replication by upregulating serpinc1 expression in Ctenopharyngodon idellus kidney (CIK) cells

Krüppel-like factor 2a (KLF2A), a transcription factor of the krüppel-like family, is involved in regulating the immune molecules and is associated with viral infection. However, the function of KLF2A during viral infections in fish remains unclear. In this study, grass carp (Ctenopharyngodon idellus) was used to predict the target genes regulated by KLF2A. The results showed that the candidate target genes included four members of the serpin gene family (serpinb1l2, serpinc1, serpinh1a, and serpinh1b). Dual-luciferase experiments showed that klf2a positively regulates serpinc1 expression. Dose-dependent klf2a overexpression in C. idellus kidney (CIK) cells significantly upregulated the expression of serpinc1. Overexpressing klf2a or serpinc1 in CIK cells activated interferon responses and suppressed grass carp reovirus (GCRV) replication. Klf2a and serpinc1 co-expression inhibited GCRV replication. These results show that klf2a upregulates serpinc1 mRNA expression, promotes type 1 interferon responses, and suppresses GCRV infection. This study provides insights into the regulatory role and biological functions of KLF2A in host-virus interactions in fish.

Glomerular cell cross talk in diabetic kidney diseases

Diabetic kidney disease (DKD) is a severe microvascular complication of diabetes mellitus. It is the leading inducement of end-stage renal disease (ESRD), and its global incidence has been increasing at an alarming rate. The strict control of blood pressure and blood glucose can delay the progression of DKD, but intensive treatment is challenging to maintain. Studies to date have failed to find a complete cure. The glomerulus's alterations and injuries play a pivotal role in the initiation and development of DKD. A wealth of data indicates that the interdependent relationship between resident cells in the glomerulus will provide clues to the mechanism of DKD and new ways for therapeutic intervention. This review summarizes the significant findings of glomerular cell cross talk in DKD, focusing on cellular signaling pathways, regulators, and potential novel avenues for treating progressive DKD.

Cellular crosstalk of glomerular endothelial cells and podocytes in diabetic kidney disease

Diabetic kidney disease (DKD) is a serious microvascular complication of diabetes and is the leading cause of end-stage renal disease (ESRD). Persistent proteinuria is an important feature of DKD, which is caused by the destruction of the glomerular filtration barrier (GFB). Glomerular endothelial cells (GECs) and podocytes are important components of the GFB, and their damage can be observed in the early stages of DKD. Recently, studies have found that crosstalk between cells directly affects DKD progression, which has prospective research significance. However, the pathways involved are complex and largely unexplored. Here, we review the literature on cellular crosstalk of GECs and podocytes in the context of DKD, and highlight specific gaps in the field to propose future research directions. Elucidating the intricates of such complex processes will help to further understand the pathogenesis of DKD and develop better prevention and treatment options.

Endothelial dysfunction in neuroprogressive disorders-causes and suggested treatments

BACKGROUND

Potential routes whereby systemic inflammation, oxidative stress and mitochondrial dysfunction may drive the development of endothelial dysfunction and atherosclerosis, even in an environment of low cholesterol, are examined.

MAIN TEXT

Key molecular players involved in the regulation of endothelial cell function are described, including PECAM-1, VE-cadherin, VEGFRs, SFK, Rho GEF TRIO, RAC-1, ITAM, SHP-2, MAPK/ERK, STAT-3, NF-κB, PI3K/AKT, eNOS, nitric oxide, miRNAs, KLF-4 and KLF-2. The key roles of platelet activation, xanthene oxidase and myeloperoxidase in the genesis of endothelial cell dysfunction and activation are detailed. The following roles of circulating reactive oxygen species (ROS), reactive nitrogen species and pro-inflammatory cytokines in the development of endothelial cell dysfunction are then described: paracrine signalling by circulating hydrogen peroxide, inhibition of eNOS and increased levels of mitochondrial ROS, including compromised mitochondrial dynamics, loss of calcium ion homeostasis and inactivation of SIRT-1-mediated signalling pathways. Next, loss of cellular redox homeostasis is considered, including further aspects of the roles of hydrogen peroxide signalling, the pathological consequences of elevated NF-κB, compromised S-nitrosylation and the development of hypernitrosylation and increased transcription of atherogenic miRNAs. These molecular aspects are then applied to neuroprogressive disorders by considering the following potential generators of endothelial dysfunction and activation in major depressive disorder, bipolar disorder and schizophrenia: NF-κB; platelet activation; atherogenic miRs; myeloperoxidase; xanthene oxidase and uric acid; and inflammation, oxidative stress, nitrosative stress and mitochondrial dysfunction.

CONCLUSIONS

Finally, on the basis of the above molecular mechanisms, details are given of potential treatment options for mitigating endothelial cell dysfunction and activation in neuroprogressive disorders.

Atorvastatin Combined with Low-Dose Dexamethasone Treatment Protects Endothelial Function Impaired by Chronic Subdural Hematoma via the Transcription Factor KLF-2

Objective

Our previous study showed that the combination therapy with atorvastatin and low-dose dexamethasone protected endothelial cell function in chronic subdural hematoma (CSDH) injury. In this study, we aimed to investigate the mechanism underlying the effects of this combination therapy on CSDH-induced cell dysfunction.

Methods

Monocytes and endothelial cells were cocultured with CSDH patient hematoma samples to mimic the pathological microenvironment of CSDH. Monocytes (THP-1 cells) and endothelial cells (hCMEC/D3 cells) were cocultured in a transwell system for 24 h before stimulation with hematoma samples diluted in endothelial cell medium (ECM) at a 1:1 ratio. Tight junction markers were detected by Western blotting, PCR and immunofluorescence. hCMEC/D3 cells were collected for Western blot and PCR analyses to detect changes in the expression levels of vascular cell adhesion molecule (VCAM-1), intercellular adhesion molecule (ICAM-1), and Kruppel-like factor 2 (KLF-2). The IL-6, IL-10 and VEGF levels in the supernatant were measured by enzyme-linked immunosorbent assay (ELISA).

Results

KLF-2 expression in endothelial cells was decreased after stimulation with CSDH patient hematoma samples, but combination therapy with atorvastatin and low-dose dexamethasone reversed this trend. KLF-2 protected injured cells by increasing the expression of VE-cadherin and ZO-1; attenuating the expression of VCAM-1, ICAM-1, IL-6 and VEGF; and enhancing the expression of IL-10, all of which play pivotal roles in endothelial inflammation. Moreover, the effect of combination therapy with atorvastatin and low-dose dexamethasone was obviously reduced in endothelial cells with KLF-2 knockdown compared with normal cells.

Conclusion

Coculture with hematoma samples decreased KLF-2 expression in human cerebral endothelial cells. Combination therapy with atorvastatin and low-dose dexamethasone counteracted hematoma-induced KLF-2 suppression in human cerebral endothelial cells to attenuate robust endothelial inflammation and permeability. KLF-2 plays an important role in drug therapy for CSDH and may become the key factor in treatment and prognosis.

Fluid flow as a driver of embryonic morphogenesis

Fluid flow is a powerful morphogenic force during embryonic development. The physical forces created by flowing fluids can either create morphogen gradients or be translated by mechanosensitive cells into biological changes in gene expression. In this Primer, we describe how fluid flow is created in different systems and highlight the important mechanosensitive signalling pathways involved for sensing and transducing flow during embryogenesis. Specifically, we describe how fluid flow helps establish left-right asymmetry in the early embryo and discuss the role of flow of blood, lymph and cerebrospinal fluid in sculpting the embryonic cardiovascular and nervous system.

Transcription Factor KLF2 and Its Role in the Regulation of Inflammatory Processes

KLF2 is a member of the Krüppel-like transcription factor family of proteins containing highly conserved DNA-binding zinc finger domains. KLF2 participates in the differentiation and regulation of the functional activity of monocytes, T lymphocytes, adipocytes, and vascular endothelial cells. The activity of KLF2 is controlled by several regulatory systems, including the MEKK2,3/MEK5/ERK5/MEF2 MAP kinase cascade, Rho family G-proteins, histone acetyltransferases CBP and p300, and histone deacetylases HDAC4 and HDAC5. Activation of KLF2 in endothelial cells induces eNOS expression and provides vasodilatory effect. Many KLF2-dependent genes participate in the suppression of blood coagulation and aggregation of T cells and macrophages with the vascular endothelium, thereby preventing atherosclerosis progression. KLF2 can have a dual effect on the gene transcription. Thus, it induces expression of multiple genes, but suppresses transcription of NF-κB-dependent genes. Transcription factors KLF2 and NF-κB are reciprocal antagonists. KLF2 inhibits induction of NF-κB-dependent genes, whereas NF-κB downregulates KLF2 expression. KLF2-mediated inhibition of NF-κB signaling leads to the suppression of cell response to the pro-inflammatory cytokines IL-1β and TNFα and results in the attenuation of inflammatory processes.

KLF2 induces the senescence of pancreatic cancer cells by cooperating with FOXO4 to upregulate p21

Pancreatic cancer is one of the most common malignancies in the world. Senescence is frequently observed in the progression of pancreatic cancer. In a previous study, we showed that KLF2 inhibited the growth and migration of pancreatic cancer. However, the mechanisms are not fully understood. In this study, we showed that overexpression of KLF2 induced the senescence of pancreatic cancer cells and inhibited tumorigenesis, and knockdown of KLF2 inhibited senescence and p21 expression. In the molecular mechanism study, KLF2 was found to interact with FOXO4 and cooperated with FOXO4 to induce the expression of p21. Downregulation of p21 and FOXO4 impaired the induction of senescence by KLF2. Overall, this study revealed the functions and mechanisms of KLF2 in senescence and provided a novel explanation for the suppressive roles of KLF2 in pancreatic cancer.

Collateral Vessels Have Unique Endothelial and Smooth Muscle Cell Phenotypes

Collaterals are unique blood vessels present in the microcirculation of most tissues that, by cross-connecting a small fraction of the outer branches of adjacent arterial trees, provide alternate routes of perfusion. However, collaterals are especially susceptible to rarefaction caused by aging, other vascular risk factors, and mouse models of Alzheimer’s disease—a vulnerability attributed to the disturbed hemodynamic environment in the watershed regions where they reside. We examined the hypothesis that endothelial and smooth muscle cells (ECs and SMCs, respectively) of collaterals have specializations, distinct from those of similarly-sized nearby distal-most arterioles (DMAs) that maintain collateral integrity despite their continuous exposure to low and oscillatory/disturbed shear stress, high wall stress, and low blood oxygen. Examination of mouse brain revealed the following: Unlike the pro-inflammatory cobble-stoned morphology of ECs exposed to low/oscillatory shear stress elsewhere in the vasculature, collateral ECs are aligned with the vessel axis. Primary cilia, which sense shear stress, are present, unexpectedly, on ECs of collaterals and DMAs but are less abundant on collaterals. Unlike DMAs, collaterals are continuously invested with SMCs, have increased expression of Pycard, Ki67, Pdgfb, Angpt2, Dll4, Ephrinb2, and eNOS, and maintain expression of Klf2/4. Collaterals lack tortuosity when first formed during development, but tortuosity becomes evident within days after birth, progresses through middle age, and then declines—results consistent with the concept that collateral wall cells have a higher turnover rate than DMAs that favors proliferative senescence and collateral rarefaction. In conclusion, endothelial and SMCs of collaterals have morphologic and functional differences from those of nearby similarly sized arterioles. Future studies are required to determine if they represent specializations that counterbalance the disturbed hemodynamic, pro-inflammatory, and pro-proliferative environment in which collaterals reside and thus mitigate their risk factor-induced rarefaction.

Krϋppel-like factors (KLFs) in renal physiology and disease

Dysregulated Krϋppel-like factor (KLF) gene expression appears in many disease-associated pathologies. In this review, we discuss physiological functions of KLFs in the kidney with a focus on potential pharmacological modulation/therapeutic applications of these KLF proteins. KLF2 is critical to maintaining endothelial barrier integrity and preventing gap formations and in prevention of glomerular endothelial cell and podocyte damage in diabetic mice. KLF4 is renoprotective in the setting of AKI and is a critical regulator of proteinuria in mice and humans. KLF6 expression in podocytes preserves mitochondrial function and prevents podocyte apoptosis, while KLF5 expression prevents podocyte apoptosis by blockade of ERK/p38 MAPK pathways. KLF15 is a critical regulator of podocyte differentiation and is protective against podocyte injury. Loss of KLF4 and KLF15 promotes renal fibrosis, while fibrotic kidneys have increased KLF5 and KLF6 expression. For therapeutic modulation of KLFs, continued screening of small molecules will promote drug discoveries targeting KLF proteins.