The human kidney capsule contains a functionally distinct mesenchymal stromal cell population

Congenital Peribronchial Myofibroblastic Tumors Harbor a Recurrent EGFR Kinase Domain Duplication

Congenital peribronchial myofibroblastic tumor (CPMT) is a rare benign infantile pulmonary neoplasm that presents prenatally, or early in infancy, and exhibits distinctive histologic features characterized by the presence of cartilaginous islands intermixed with bland spindle cells, not uncommonly displaying prominent mitoses. Despite its benign nature, CPMT can lead to fetal demise, postnatal respiratory distress, or complications from perinatal surgical resection. Although the morphologic and clinical features of CPMT are well described, its molecular features and oncogenesis remain elusive. Following the detection of EGFR kinase domain duplication (KDD) of exons 18 to 25 in an index case, we identified 3 additional cases of morphologically classic and clinically well-characterized CPMTs from the archives and performed targeted RNA- and DNA-based profiling via next-generation sequencing for detection of rearrangements, sequence variants, and copy number variants on all cases. Two cases were detected prenatally, 1 patient presented at birth, and 1 at 8 weeks of life. All tumors were resected, with a follow-up period ranging from 0 days to 10 years. One patient died shortly after surgical resection, and the other 3 had no recurrences. In all cases, EGFR KDD was detected. In 2 out of 4 cases, gains of select whole chromosomes were noted. Our findings establish EGFR KDD as a recurrent oncogenic driver of CPMT. Notably, this alteration is also found in classical congenital mesoblastic nephromas, infantile kidney tumors with which CPMTs share striking morphologic and clinical similarities. This strongly suggests that CPMTs and classical congenital mesoblastic nephromas share common oncogenesis, and represent the same tumor in different locations. EGFR KDDs have also been reported in neonatal soft tissue tumors with infantile fibrosarcoma-like histology and cartilaginous differentiation, raising questions about their relationship. EGFR KDD emerges as a diagnostic marker, a potential therapeutic target, and a window into the oncogenesis of a distinct subset of infantile mesenchymal tumors.

Engineering pH-sensitive dissolution of lipid-polymer nanoparticles by Eudragit integration impacts plasmid DNA (pDNA) transfection

Lipid-polymer nanoparticles offer a promising strategy for improving gene nanomedicines by combining the benefits of biocompatibility and stability associated with the individual systems. However, research to date has focused on poly-lactic-co-glycolic acid (PLGA) and resulted in inefficient transfection. In this study, biocompatible Eudragit constructs E100 and RS100 were formulated as lipid-polymer nanoparticles loaded with pDNA expressing red fluorescent protein (RFP) as a model therapeutic. Using a facile nanoprecipitation technique, a core-shell structure stabilised by lipid-polyethylene glycol (PEG) surfactant was produced and displayed resistance to ultracentrifugation. Both cationic polymers E100 (pH-sensitive dissolution at 5) and RS100 (pH-insensitive dissolution) produced 150-200 nm sized particles with a small positive surface charge (+3-5 mV) and high pDNA encapsulation efficiencies (EE) of 75-90%. The dissolution properties of the Eudragit polymers significantly impacted the biological performance in human embryonic kidney cells (HEK293T). Nanoparticles composed of polymer RS100 resulted in consistently high cell viability (80-100%), whereas polymer E100 demonstrated dose-dependent behaviour (20-90% cell viability). The low dissolution of polymer RS100 over the full pH range and the resulting nanoparticles failed to induce RFP expression in HEK293T cells. In contrast, polymer E100-constructed nanoparticles resulted in reproducible and gradually increasing RFP expression of 26-42% at 48-72 h. Intraperitoneal (IP) injection of the polymer E100-based nanoparticles in C57BL/6 mice resulted in targeted RFP expression in mouse testes with favourable biocompatibility one-week post-administration. These findings predicate Eudragit based lipid-polymer nanoparticles as a novel and effective carrier for nucleic acids, which could facilitate pre-clinical evaluation and translation of gene nanomedicines.

Renal Congestion in Heart Failure: Insights in Novel Diagnostic Modalities

Heart failure is increasingly prevalent and is estimated to increase its burden in the following years. A well-reported comorbidity of heart failure is renal dysfunction, where predominantly changes in the patient's volume status, tubular necrosis or other mechanical and neurohormonal mechanisms seem to drive this impairment. Currently, there are established biomarkers evaluating the patient's clinical status solely regarding the cardiovascular or renal system. However, as the coexistence of heart and renal failure is common and related to increased mortality and hospitalization for heart failure, it is of major importance to establish novel diagnostic techniques, which could identify patients with or at risk for cardiorenal syndrome and assist in selecting the appropriate management for these patients. Such techniques include biomarkers and imaging. In regards to biomarkers, several peptides and miRNAs indicative of renal or tubular dysfunction seem to properly identify patients with cardiorenal syndrome early on in the course of the disease, while changes in their serum levels can also be helpful in identifying response to diuretic treatment. Current and novel imaging techniques can also identify heart failure patients with early renal insufficiency and assess the volume status and the effect of treatment of each patient. Furthermore, by assessing the renal morphology, these techniques could also help identify those at risk of kidney impairment. This review aims to present all relevant clinical and trial data available in order to provide an up-to-date summary of the modalities available to properly assess cardiorenal syndrome.

Pericyte detachment and renal congestion involve interstitial injury and fibrosis in Dahl salt-sensitive rats and humans with heart failure

Congestive heart failure produces fluid volume overload, central and renal venous pressure elevation, and consequently renal congestion, which results in worsening renal function. Pericyte detachment and pericyte-myofibroblast transition (PMT) were linked to renal interstitial fibrosis. Dahl salt-sensitive hypertensive (DahlS) rats are a non-surgical renal congestion model. The relation, however, between renal interstitial damage, pericyte morphology, and PMT in the renal congestion of DahlS rats has not been reported. DahlS rats (8-week-old) were fed normal salt (NS, 0.4% NaCl) or high salt (HS, 4% NaCl), and the left kidney was decapsulated to reduce renal interstitial hydrostatic pressure (RIHP) at 9 weeks old. One week after capsulotomy, both kidneys were analyzed by molecular and histological techniques. Renal pericyte structure was assessed in the body donors with/without venous stasis. Markers of tubulointerstitial damage, interstitial fibrosis, and PMT were upregulated in the right non-decapsulated kidney of DahlS rats fed HS. Renal tubular injury and fibrosis were detected in the HS diet groups in histological analysis. Pericyte detachment was observed in the right non-decapsulated kidney of DahlS rats fed HS by low vacuum-scanning electron microscopy. Decapsulation in DahlS rats fed HS attenuated these findings. Also, renal pericytes detached from the vascular wall in patients with heart failure. These results suggest that pericyte detachment and PMT induced by increased RIHP are responsible for tubulointerstitial injury and fibrosis in DahlS rats and humans with renal congestion. Renal venous congestion and subsequent physiological changes could be therapeutic targets for renal damage in cardiorenal syndrome.

Renal Compression in Heart Failure: The Renal Tamponade Hypothesis

Renal dysfunction is one of the strongest predictors of outcome in heart failure. Several studies have revealed that both reduced perfusion and increased congestion (and central venous pressure) contribute to worsening renal function in heart failure. This paper proposes a novel factor in the link between cardiac and renal dysfunction: "renal tamponade" or compression of renal structures caused by the limited space for expansion. This space can be limited either by the rigid renal capsule that encloses the renal interstitial tissue or by the layer of fat around the kidneys or by the peritoneal space exerting pressure on the retroperitoneal kidneys. Renal decapsulation in animal models of heart failure and acute renal ischemia has been shown effective in alleviating pressure-related injury within the kidney itself, thus supporting this concept and making it a potentially interesting novel treatment in heart failure.

The functions of clusterin in renal mesenchymal stromal cells: Promotion of cell growth and regulation of macrophage activation

Clusterin (CLU) increases resistance to renal ischemia-reperfusion injury and promotes renal tissue repair. However, the mechanisms underlying of the renal protection of CLU remain unknown. Mesenchymal stromal cells (MSCs) may contribute to kidney cell turnover and injury repair. This study investigated the in vitro functions of CLU in kidney mesenchymal stromal cells (KMSCs). KMSCs were grown in plastic culture plates. Cell surface markers, apoptosis and phagocytosis were determined by flow cytometry, and CLU protein by Western blot. There were no differences in the expression of MSC markers (positive: CD133, Sca-1, CD44, CD117 and NG2, and negative: CD34, CD45, CD163, CD41, CD276, CD138, CD79a, CD146 and CD140b) and in the trilineage differentiation to chondrocytes, adipocytes and osteocytes between wild type (WT) and CLU knockout (KO) KMSCs. CLU was expressed intracellularly and secreted by WT KMSCs, and it was up-regulated by hypoxia. CLU did not prevent hypoxia-induced cell apoptosis but promoted cell growth in KMSC cultures. Furthermore, incubation with CLU-containing culture medium from WT KMSCs increased CD206 expression and phagocytic capacity of macrophages. In conclusion, our data for the first time demonstrate the function of CLU in the promotion of KMSCs proliferation, and it may be required for KMSCs-regulated macrophage M2 polarization and phagocytic activity.

Renal cell markers: lighthouses for managing renal diseases

Kidneys, one of the vital organs in our body, are responsible for maintaining whole body homeostasis. The complexity of renal function (e.g., filtration, reabsorption, fluid and electrolyte regulation, and urine production) demands diversity not only at the level of cell types but also in their overall distribution and structural framework within the kidney. To gain an in depth molecular-level understanding of the renal system, it is imperative to discern the components of kidney and the types of cells residing in each of the subregions. Recent developments in labeling, tracing, and imaging techniques have enabled us to mark, monitor, and identify these cells in vivo with high efficiency in a minimally invasive manner. In this review, we summarize different cell types, specific markers that are uniquely associated with those cell types, and their distribution in the kidney, which altogether make kidneys so special and different. Cellular sorting based on the presence of certain proteins on the cell surface allowed for the assignment of multiple markers for each cell type. However, different studies using different techniques have found contradictions in cell type-specific markers. Thus, the term "cell marker" might be imprecise and suboptimal, leading to uncertainty when interpreting the data. Therefore, we strongly believe that there is an unmet need to define the best cell markers for a cell type. Although the compendium of renal-selective marker proteins presented in this review is a resource that may be useful to researchers, we acknowledge that the list may not be necessarily exhaustive.

Diabetic Kidney Disease Alters the Transcriptome and Function of Human Adipose-Derived Mesenchymal Stromal Cells but Maintains Immunomodulatory and Paracrine Activities Important for Renal Repair

Mesenchymal stem/stromal cells (MSCs) facilitate repair in experimental diabetic kidney disease (DKD). However, the hyperglycemic and uremic milieu may diminish regenerative capacity of patient-derived therapy. We hypothesized that DKD reduces human MSC paracrine function. Adipose-derived MSC from 38 participants with DKD and 16 control subjects were assessed for cell surface markers, trilineage differentiation, RNA sequencing (RNA-seq), in vitro function (coculture or conditioned medium experiments with T cells and human kidney cells [HK-2]), secretome profile, and cellular senescence abundance. The direction of association between MSC function and patient characteristics were also tested. RNA-seq analysis identified 353 differentially expressed genes and downregulation of several immunomodulatory genes/pathways in DKD-MSC versus Control-MSC. DKD-MSC phenotype, differentiation, and tube formation capacity were preserved, but migration was reduced. DKD-MSC with and without interferon-γ priming inhibited T-cell proliferation greater than Control-MSC. DKD-MSC medium contained higher levels of anti-inflammatory cytokines (indoleamine 2,3-deoxygenase 1 and prostaglandin-E2) and prorepair factors (hepatocyte growth factor and stromal cell-derived factor 1) but lower IL-6 versus control-MSC medium. DKD-MSC medium protected high glucose plus transforming growth factor-β-exposed HK-2 cells by reducing apoptotic, fibrotic, and inflammatory marker expression. Few DKD-MSC functions were affected by patient characteristics, including age, sex, BMI, hemoglobin A_1c, kidney function, and urine albumin excretion. However, senescence-associated β-galactosidase activity was lower in DKD-MSC from participants on metformin therapy. Therefore, while DKD altered the transcriptome and migratory function of culture-expanded MSCs, DKD-MSC functionality, trophic factor secretion, and immunomodulatory activities contributing to repair remained intact. These observations support testing of patient-derived MSC therapy and may inform preconditioning regimens in DKD clinical trials.