Hypoxia enhances anti-fibrotic properties of extracellular vesicles derived from hiPSCs via the miR302b-3p/TGFβ/SMAD2 axis

BACKGROUND

Cardiac fibrosis is one of the top killers among fibrotic diseases and continues to be a global unaddressed health problem. The lack of effective treatment combined with the considerable socioeconomic burden highlights the urgent need for innovative therapeutic options. Here, we evaluated the anti-fibrotic properties of extracellular vesicles (EVs) derived from human induced pluripotent stem cells (hiPSCs) that were cultured under various oxygen concentrations.

METHODS

EVs were isolated from three hiPSC lines cultured under normoxia (21% O2; EV-N) or reduced oxygen concentration (hypoxia): 3% O2 (EV-H3) or 5% O2 (EV-H5). The anti-fibrotic activity of EVs was tested in an in vitro model of cardiac fibrosis, followed by a detailed investigation of the underlying molecular mechanisms. Sequencing of EV miRNAs combined with bioinformatics analysis was conducted and a selected miRNA was validated using a miRNA mimic and inhibitor. Finally, EVs were tested in a mouse model of angiotensin II-induced cardiac fibrosis.

RESULTS

We provide evidence that an oxygen concentration of 5% enhances the anti-fibrotic effects of hiPS-EVs. These EVs were more effective in reducing pro-fibrotic markers in activated human cardiac fibroblasts, when compared to EV-N or EV-H3. We show that EV-H5 act through the canonical TGFβ/SMAD pathway, primarily via miR-302b-3p, which is the most abundant miRNA in EV-H5. Our results show that EV-H5 not only target transcripts of several profibrotic genes, including SMAD2 and TGFBR2, but also reduce the stiffness of activated fibroblasts. In a mouse model of heart fibrosis, EV-H5 outperformed EV-N in suppressing the inflammatory response in the host and by attenuating collagen deposition and reducing pro-fibrotic markers in cardiac tissue.

CONCLUSIONS

In this work, we provide evidence of superior anti-fibrotic properties of EV-H5 over EV-N or EV-H3. Our study uncovers that fine regulation of oxygen concentration in the cellular environment may enhance the anti-fibrotic effects of hiPS-EVs, which has great potential to be applied for heart regeneration.

[Parental ageing and Assisted Reproduction Technologies: analysis of risk of chronic diseases in the progeny]

Conception of a child at advanced parental age (> 35 years) has been steadily increasing in recent decades, especially in developed countries. Socio-economic factors, effective contraceptives, and the availability of Assisted Reproduction Technologies (ART) have a direct impact on postponing the decision to have a baby. ART enables reproductive success for people diagnosed as infertile or with reduced possibilities of becoming pregnant due to concomitant pathologies. Epidemiological studies indicate that both advanced parental age and ART are associated with pathologies of pregnancy, such as gestational diabetes, risk of pre-eclampsia, miscarriage, placental abruption, preterm labor, stillbirth, neurodevelopmental disorders and chronic disease of the offspring. In our work, we will focus on the available information on metabolic changes that increase the risk of developing cardiovascular diseases in the offspring of parents at an advanced age and conceived through ART. Finally, we will address the sources of the observed disturbances at the gamete and embryo level, related to oxygen stress, epigenetic modifications and DNA damage, considering possible rescue actions.

Ribosomal DNA methylation in human and mouse oocytes increases with age

An age-dependent increase in ribosomal DNA (rDNA) methylation has been observed across a broad spectrum of somatic tissues and the male mammalian germline. Bisulfite pyrosequencing (BPS) was used to determine the methylation levels of the rDNA core promoter and the rDNA upstream control element (UCE) along with two oppositely genomically imprinted control genes (PEG3 and GTL2) in individual human germinal vesicle (GV) oocytes from 90 consenting women undergoing fertility treatment because of male infertility. Apart from a few (4%) oocytes with single imprinting defects (in either PEG3 or GTL2), the analyzed GV oocytes displayed correct imprinting patterns. In 95 GV oocytes from 42 younger women (26-32 years), the mean methylation levels of the rDNA core promoter and UCE were 7.4±4.0% and 9.3±6.1%, respectively. In 79 GV oocytes from 48 older women (33-39 years), methylation levels increased to 9.3±5.3% (P = 0.014) and 11.6±7.4% (P = 0.039), respectively. An age-related increase in oocyte rDNA methylation was also observed in 123 mouse GV oocytes from 29 4-16-months-old animals. Similar to the continuously mitotically dividing male germline, ovarian aging is associated with a gain of rDNA methylation in meiotically arrested oocytes. Oocytes from the same woman can exhibit varying rDNA methylation levels and, by extrapolation, different epigenetic ages.

The Effect of Acetylcysteine on Renal Function in Experimental Models of Cyclophosphamide-and Ifosfamide-Induced Cystitis

Introduction

Urotoxicity is a characteristic attribute of cy-clophosphamide and ifosfamide. Acetylcysteine is perceived as a uroprotective and possible nephroprotective compound. The purpose of the study was to assess the effect of acetylcysteine treatment on the morphology of the kidneys and the urinary bladder, and renal function in rats with cystitis induced by cyclophosphamide or ifosfamide.

Methods

Cystitis was induced in rats belonging to groups 2 and 3, as well as 4 and 5, by five administrations of cyclophosphamide (75 mg/kg) or ifosfamide (80 mg/kg) respectively. Additionally, groups 3 and 5 received acetylcysteine (200 mg/kg). Group 1 was "sham treated" as a control. Upon conclusion of the experiment, the animals were euthanized and their kidneys and urinary bladders were collected for histopathological analysis. The assessment of renal function was based on classic nitrogen blood parameters (urea, creatinine, and uric acid), as well as proteinuria and cystatin C (CysC) and kidney injury molecule-1 (KIM-1) urinary concentrations, and their 24-hour elimination with urine.

Results

Reduction of blood urea nitrogen and uric acid, and urinary pH with a significant increase of CysC and KIM-1 urinary concentrations, and their 24-hour elimination with urine were observed in groups 2 and 4. The acetylcysteine treatment did not cause a significant change of blood parameters, but significantly decreased 24-hour elimination of CysC and KIM-1 with urine, and accounted for alleviation of the histopathological abnormalities of urinary bladders, with no significant effects on the structure of the kidneys.

Conclusions

Acetylcysteine used in the experimental model of cyclophosphamide- and ifosfamide-induced cystitis had a uroprotective effect and also reduced renal dysfunction, which suggests its potential use as a nephroprotective compound in cyclophosphamide/ifosfamide therapy.

Osteopontin and Fatty Acid Binding Protein in Ifosfamide-treated Rats

Introduction

Ifosfamide (IF) is a cytostatic that exhibits adverse nephrotoxic properties. Clinically, IF-induced nephrotoxicity takes various forms, depending on applied dose and length of treatment.

Objectives

The aim of the study was to evaluate the two proteins: osteopontin (OP) and fatty acid binding protein (FABP), as markers of kidney function in rats treated with ifosfamide.

Material and Methods

Rats receiving a single IF dose (250 mg/kg b.w.; group 1) or treated with five consecutive IF doses administrated on following days (50mg/kg b.w.; group 3), compared with control groups 2 and 4, respectively, were studied. Kidney function was assessed using classical (urea, creatinine) and novel (FABP, OP) laboratory parameters and by histopathology.

Results

Single IF dose administration resulted in significant total proteinuria with urinary concentrations and 24-hour excretions of both FABP and OP comparable to the appropriate control. In rats treated with five consecutive IF doses, the urinary concentrations and 24-hour excretion of both FABP and OP were significantly higher compared to the appropriate control. The development of cystitis was revealed in groups 1 and 3, which was not accompanied by significant histopathological kidney damage.

Conclusions

Both OP and FABP may be useful laboratory markers of tubulopathy in the early stage of chronic nephrotoxicity of ifosfamide.

Osteopontin and fatty acid binding protein (FABP), as biomarkers of cyclophosphamide nephrotoxicity, in an experimental model of cystitis in rats

Aim: Cyclophosphamide (CP) is a cytostatic agent, which evokes numerous side effects, including well-known cystitis. Acrolein released during CP biotransformation exerts both urotoxic and nephrotoxic effects, therefore CP may cause renal dysfunction. The aim of the study was to assess kidney function in experimental models of acute and chronic cystitis. Material/Methods: The studies were carried out on 40 rats (4 groups; n = 10), in which acute (single dose of 150 mg/kg CP; group 2) or chronic (four doses of 75 mg/kg CP; group 4) cystitis was induced with appropriate control groups (group 1 and 3). Renal function was assessed with standard (diuresis, urea, creatinine) and new (fatty acid binding protein – FABP and osteopontin) laboratory parameters as well as histopathologically. Results: The histopathological assessment confirmed the presence of acute and chronic cystitis and did not reveal coexisting significant kidney disorders in groups 2 and 4. Group 2 retained urea and creatinine in the blood. Both groups 2 and 4 showed an increase in diurnal diuresis, and a decreased concentration of urea and creatinine was found in the urine, which was accompanied by significant proteinuria. The daily urinary excretion of small-molecule nitrogen compounds did not differ from the values found in the control groups. In addition, both groups 2 and 4 showed an increase in urinary concentration and excretion of FABP and osteopontin with urine. Conclusions: The experiment revealed the renal dysfunction in the course of cyclophosphamide-induced cystitis with the tubulopathy character, expressed by the increased production and release into the urine two markers reflecting acute kidney injury – FABP and osteopontin.

The effect of cumulus cells on domestic cat (Felis catus) oocytes during in vitro maturation and fertilization

The aim of this study was to evaluate the effect of co-culture of denuded oocytes with cumulus cells (CC) or cumulus-oocyte complexes (COCs) on in vitro maturation (IVM) and in vitro fertilization (IVF). Immature oocytes were collected from ovaries of domestic cats following a routine ovariectomy. Oocytes were matured in vitro for 24 hr within four groups: (i) denuded oocytes (DO), (ii) DO co-cultured with CC, (iii) DO co-cultured with COC and (iv) COC as a control group. In further experiments, COCs were matured in vitro for 24 hr, and then, oocytes were randomly divided into four groups as previously described and fertilized in vitro. Embryos were cultured for up to 7 days. At the end of each experiment, oocytes/embryos were stained with Hoechst 33342 solution and observed under an inverted fluorescence microscope. The results of oocyte maturation showed that their meiotic competence decreased significantly in all experimental groups, compared to the control group. The maturation rates were approximately 45%, 24%, 43% and 76% in experiment 1, and 21%, 14%, 33% and 50% in experiment 2 in groups (i), (ii), (iii) and (iv), respectively. Examination of in vitro fertilization revealed that embryos developed up to the morula stage in all experimental groups. DO and oocytes cultured with COC during fertilization showed a lower cleavage rate-36% and 25% as opposed to those co-cultured with loose CC and the control group-43% and 42%, respectively. Results of this study indicate that cumulus cells connected with an oocyte into a cumulus-oocyte complex are irreplaceable for the maturation of domestic cat oocyte, but that the addition of loose CC may be beneficial for IVF.

Continuous fast Fourier transform admittance voltammetry as a new approach for studying the change in morphology of polyaniline for supercapacitors application

In this study, continuous fast Fourier transform admittance voltammetry (CFFTAV) was used to study and characterize the surface morphology of polyaniline (PANI) on glassy carbon (GC) electrodes.