An experienced racial-ethnic diversity dataset in the United States using human mobility data.

Despite the importance of measuring racial-ethnic segregation and diversity in the United States, current measurements are largely based on the Census and, thus, only reflect segregation and diversity as understood through residential location. This leaves out the social contexts experienced throughout the course of the day during work, leisure, errands, and other activities. The National Experienced Racial-ethnic Diversity (NERD) dataset provides estimates of diversity for the entire United States at the census tract level based on the range of place and times when people have the opportunity to come into contact with one another. Using anonymized and opted-in mobile phone location data to determine co-locations of people and their demographic backgrounds, these measurements of diversity in potential social interactions are estimated at 38.2 m × 19.1 m scale and 15-minute timeframe for a representative year and aggregated to the Census tract level for purposes of data privacy. As well, we detail some of the characteristics and limitations of the data for potential use in national, comparative studies.

Financial globalization and economic growth amid geopolitical risk: A study on China-Russia far East federal district.

Geopolitics, natural resource efficiency and financial globalization have arisen as a new concept for low CO2 to achieve sustainable economic growth (EG). Therefore, developed and developing economies focus on Geopolitics risk (GPR), natural resource (NRS) efficiency and financial globalization (FG) to cope with CO2 neutrality targets. In order to understand the elements that contribute to achieving CO2 neutrality, this study sought to establish a relevant connection between geopolitics, the efficiency of NRS, financial globalization (FNG), and economic growth. For the abovementioned objectives, modern econometric methods, such as the canonical cointegration, CS-FGLS and GMM were adopted to evaluate the China-Russia Far East dataset between 1990 and 2022. In order to achieve CO2 neutrality in the long run, the study's elements are crucial, according to the results. In addition, GMM shows that each of the parameters affects CO2 neutrality. As a result, the ecological Kuznets curve rules the economic landscape, and long-term CO2 neutrality is greatly facilitated by geopolitics, efficient use of natural resources, financial globalization, and economic growth. Consequently, numerous domains necessitate far-reaching and revolutionary policy changes, such as economic integration to mitigate geopolitical risk, effective management of natural resources, efficient financial systems, and sustainable technology.

Recharging exhausted parents: How and when involvement in children's education increases working parents' flourishing at home and engagement at work.

Parental involvement in children's education is highly valued and encouraged in many societies. While existing research has mainly focused on the positive effects parental involvement has for children, we argue that engaging in such quality parent-child interactions can also be a resource-gaining process for parents. Drawing on the conservation of resources theory and the work-home resources model, the current study aims to investigate how and when working parents' involvement in children's education enhances their well-being at home and engagement at work. Using a two-wave survey of 206 full-time employees with at least one school-aged child, our results indicate that for parents experiencing higher levels of parental burnout, involvement in their children's education enhances their flourishing experience at home and subsequently improves work engagement and creative process engagement at work. Overall, our study contributes to the well-being and work-family interface literature by highlighting the positive effect of parental involvement, an underexplored construct, on working parents' well-being both at home and in the workplace. This study also provides practical implications for burned-out working parents that they can benefit from involving themselves in their children's education to cope with and thrive from family demands.

A phospholipid:diacylglycerol acyltransferase is involved in the regulation of phospholipids homeostasis in oleaginous Aurantiochytrium sp.

BACKGROUND: Thraustochytrids have gained attention as a potential source for the production of docosahexaenoic acid (DHA), where DHA is predominantly stored in the form of triacylglycerol (TAG). The TAG biosynthesis pathways, including the acyl-CoA-dependent Kennedy pathway and the acyl-CoA-independent pathway, have been predicted in thraustochytrids, while the specific details regarding their roles are currently uncertain. RESULTS: Phospholipid:diacylglycerol acyltransferase (PDAT) plays a key role in the acyl-CoA-independent pathway by transferring acyl-group from phospholipids (PL) to diacylglycerol (DAG) to from TAG. In thraustochytrid Aurantiochytrium sp. SD116, an active AuPDAT was confirmed by heterologous expression in a TAG-deficient yeast strain H1246. Analysis of AuPDAT function in vivo revealed that deletion of AuPDAT led to slow growth and a significant decrease in cell number, but improved PL content in the single cell during the cell growth and lipid accumulation phases. Interestingly, deletion of AuPDAT did not affect total lipid and TAG content, but both were significantly increased within a single cell. Moreover, overexpression of AuPDAT also resulted in a decrease in cell number, while the total lipid and cell diameter of a single cell were markedly increased. Altogether, both up-regulation and down-regulation of AuPDAT expression affected the cell number, which further associated with the total lipid and TAG content in a single cell. CONCLUSIONS: Our study demonstrates that AuPDAT-mediated pathway play a minor role in TAG synthesis, and that the function of AuPDAT may be involved in regulating PL homeostasis by converting PL to TAG in a controlled manner. These findings expand our understanding of lipid biosynthesis in Aurantiochytrium sp. and open new avenues for developing "customized cell factory" for lipid production.

Correction to: Well­Being Reduces COVID­19 Anxiety: A Three­Wave Longitudinal Study in China.

[This corrects the article DOI: 10.1007/s10902-021-00385-2.].

Cocktail biosynthesis of triacylglycerol by rational modulation of diacylglycerol acyltransferases in industrial oleaginous Aurantiochytrium.

BACKGROUND: Triacylglycerol (TAG) is an important storage lipid in organisms, depending on the degree of unsaturation of fatty acid molecules attached to glycerol; it is usually used as the feedstock for nutrition or biodiesel. However, the mechanism of assembly of saturated fatty acids (SFAs) or polyunsaturated fatty acids (PUFAs) into TAGs remains unclear for industrial oleaginous microorganism. RESULTS: Diacylglycerol acyltransferase (DGAT) is a key enzyme for TAG synthesis. Hence, ex vivo (in yeast), and in vivo functions of four DGAT2s (DGAT2A, DGAT2B, DGAT2C, and DGAT2D) in industrial oleaginous thraustochytrid Aurantiochytrium sp. SD116 were analyzed. Results revealed that DGAT2C was mainly responsible for connecting PUFA to the sn-3 position of TAG molecules. However, DGAT2A and DGAT2D target SFA and/or MUFA. CONCLUSIONS: There are two specific TAG assembly routes in Aurantiochytrium. The "saturated fatty acid (SFA) TAG lane" primarily produces SFA-TAGs mainly mediated by DGAT2D whose function is complemented by DGAT2A. And, the "polyunsaturated fatty acid (PUFA) TAG lane" primarily produces PUFA-TAGs via DGAT2C. In this study, we demonstrated the functional distribution pattern of four DGAT2s in oleaginous thraustochytrid Aurantiochytrium, and provided a promising target to rationally design TAG molecular with the desired characteristics.

Obtaining High-Purity Docosahexaenoic Acid Oil in Thraustochytrid Aurantiochytrium through a Combined Metabolic Engineering Strategy.

High-purity docosahexaenoic acid (DHA) resources are insufficient in the pharmaceutical and food industries. Although many efforts have attempted to obtain the high-purity DHA production, few reports have been successful. Here, a combined metabolic engineering strategy was employed to increase the DHA purity in the oleaginous thraustochytrid Aurantiochytrium. The strategy includes both partial deactivation of the competing pathway of DHA biosynthesis, by disrupting one copy of the fatty acid synthase gene, and strengthening of substrate supply and triacylglycerol synthesis, by the overexpression of acetyl-CoA carboxylase and diacylglycerol acyltransferase. With this strategy, a final mutant was obtained with a DHA purity of 61% in total fatty acids and a content of 331 mg/g dry cell weight. This study provides an advanced strategy for sustainable high-purity DHA production and highlights the strategy for producing designer oils in industrial oleaginous microorganisms.

Well-Being Reduces COVID-19 Anxiety: A Three-Wave Longitudinal Study in China.

The coronavirus disease 2019 (COVID-19) pandemic threatens human beings' livelihoods and mental health, which lowers their well-being and gives rise to anxiety. This study examines whether there is a causal relationship (and, if so, in which direction) between people's well-being and COVID-19 anxiety. Two hundred and twenty-two participants (54.50% female, M age = 31.53, SD = 8.17) from 26 provinces of China completed measures of subjective well-being (SWB) and COVID-19 anxiety at three key nodes of the development of COVID-19 in China. The results showed that people's SWB and COVID-19 anxiety fluctuated with the peak (T1), decline (T2), and trough stages (T3) of the COVID-19 pandemic. Meanwhile, the cross-lagged analysis showed that the participants' SWB at T0 (pre-pandemic stage; the base level of SWB) and T1 could significantly predict their COVID-19 anxiety at T1 and T2 respectively. However, SWB at T2 was not associated with the COVID-19 anxiety at T3. Furthermore, COVID-19 anxiety could not predict subsequent SWB from T1 to T3. The current findings contribute to clarifying the causal relationship between well-being and anxiety through the development of epidemics, as well as finding ways to alleviate people's COVID-19 anxiety. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10902-021-00385-2.

Enhanced renoprotective effect of GDNF-modified adipose-derived mesenchymal stem cells on renal interstitial fibrosis.

BACKGROUND: The therapeutic effect of mesenchymal stem cells (MSCs) from human adipose tissue on renal interstitial fibrosis has been demonstrated by several groups. However, the way to enhance the renoprotective effect of adipose-derived mesenchymal stem cells (AMSCs) and the possible mechanisms are still unclear. The present study aimed to determine whether glial cell line-derived neurotrophic factor (GDNF)-modified AMSCs hold an enhanced protective effect on renal fibrosis. METHODS: AMSCs were isolated and purified for culture. The gene GDNF has been constructed to transfect into AMSCs. The ability of GFP-AMSCs and GDNF-AMSCs supernatants to promote tube formation of endothelial cells, repair damaged endothelial cell junctions, and improve endothelial cell function was compared by using tube formation assay, immunofluorescence techniques, and vascular ring assay, respectively. Furthermore, HE and Masson staining were used to observe the histological morphology of the kidney in vivo. Peritubular capillary changes were detected and analyzed by fluorescence microangiography (FMA). Meanwhile, the hypoxia, oxidative stress, fibrotic markers, and PI3K/Akt pathway proteins were measured by western blot or qRT-PCR technics. RESULTS: Compared with GFP-AMSCs only, GDNF-AMSCs could enhance the repair of injured endothelial cells and promote angiogenesis through secreting more growth factors in the supernatant of GDNF-AMSC culture media demonstrated in vitro studies. Studies in vivo, unilateral ureteral obstruction (UUO)-induced mice were injected with transfected AMSCs through their tail veins. We showed that enhanced homing of AMSCs was observed in the GDNF-AMSC group compared with the GFP-AMSC group. The animals treated with GDNF-AMSCs exhibited an improvement of capillary rarefaction and fibrosis induced by obstructed kidney compared with the GFP-AMSC group. Furthermore, we reported that GDNF-AMSCs protect renal tissues against microvascular injuries via activation of the PI3K/Akt signaling pathway. Therefore, GDNF-AMSCs further ameliorated the tissue hypoxia, suppressed oxidative stress, and finally inhibited endothelial to mesenchymal transition noting by decreased coexpression of endothelial cell (CD31) and myofibroblast (a-SMA) markers. CONCLUSION: Collectively, our data indicated that the GDNF gene enhances the ability of AMSCs in improving renal microcirculation through PI3K/Akt/eNOS signaling pathway and afterward inhibit the EndMT process and kidney fibrogenesis, which should have a vast of implications in designing future remedies for chronic kidney disease (CKD) treatment.

A Two-Stage Adaptive Laboratory Evolution Strategy to Enhance Docosahexaenoic Acid Synthesis in Oleaginous Thraustochytrid.

Thraustochytrid is a promising algal oil resource with the potential to meet the demand for docosahexaenoic acid (DHA). However, oils with high DHA content produced by genetic modified thraustochytrids are not accepted by the food and pharmaceutical industries in many countries. Therefore, in order to obtain non-transgenic strains with high DHA content, a two-stage adaptive laboratory evolution (ALE) strategy was applied to the thraustochytrid Aurantiochytrium sp. Heavy-ion irradiation technique was first used before the ALE to increase the genetic diversity of strains, and then two-step ALE: low temperature based ALE and ACCase inhibitor quizalofop-p-ethyl based ALE were employed in enhancing the DHA production. Using this strategy, the end-point strain E-81 with a DHA content 51% higher than that of the parental strain was obtained. The performance of E-81 strain was further analyzed by component analysis and quantitative real-time PCR. The results showed that the enhanced in lipid content was due to the up-regulated expression of key enzymes in lipid accumulation, while the increase in DHA content was due to the increased transcriptional levels of polyunsaturated fatty acid synthase. This study demonstrated a non-genetic approach to enhance lipid and DHA content in non-model industrial oleaginous strains.

Perceived Social Support Protects Lonely People Against COVID-19 Anxiety: A Three-Wave Longitudinal Study in China.

The isolation necessary to prevent the spread of the coronavirus disease 2019 (COVID-19) can give rise to anxiety, especially for lonely people who often feel upset without others' company. Although isolated from others, people can still receive support from others, which might lower their COVID-19 anxiety. To examine the relationship between loneliness, perceived social support, and anxiety, we measured 222 Chinese participants' (54.50% female, M age = 31.53, SD = 8.17) trait loneliness, chronic anxiety before the outbreak, COVID-19 anxiety at the peak and decline stages of COVID-19, and their perceived social support across the three time points. The results showed that people's perceived social support dramatically increased from the pre-pandemic to the peak COVID-19 stage, and remained stable during the decline of COVID-19 stage. In contrast, COVID-19 anxiety decreased from the peak to the decline stage. Further, perceived social support consistently moderated the relationship between loneliness with both chronic anxiety and COVID-19 anxiety. The current study provides initial evidence that perceived social support provides protection for lonely people in daily life as well as during unexpected disasters, which will contribute to finding ways to alleviate lonely people's anxiety during this global health crisis.

PUFA-synthase-specific PPTase enhanced the polyunsaturated fatty acid biosynthesis via the polyketide synthase pathway in Aurantiochytrium.

BACKGROUND: Phosphopantetheinyl transferase (PPTase) can change the acyl-carrier protein (ACP) from an inactive apo-ACP to an active holo-ACP that plays a key role in fatty acids biosynthesis. Currently, the PPTase has been proved to be involved in the biosynthesis of polyunsaturated fatty acids (PUFAs) via a polyketide synthase (PKS) pathway in Thraustochytrids, while its characteristics are not clarified. RESULTS: Here, the heterologous PPTase gene (pfaE) from bacteria was first co-expressed with the PKS system (orfA-orfC) from Thraustochytrid Aurantiochytrium. Then, a new endogenous PPTase (ppt_a) in Aurantiochytrium was identified by homologous alignment and its function was verified in E. coli. Moreover, the endogenous ppt_a was then overexpressed in Aurantiochytrium, and results showed that the production and proportion of PUFAs, especially docosahexaenoic acid (DHA), in the transformant SD116::PPT_A were increased by 35.5% and 17.6%, respectively. Finally, higher DHA and PUFA proportion (53.9% and 64.5% of TFA, respectively) were obtained in SD116::PPT_A using a cerulenin feeding strategy. CONCLUSIONS: This study has illustrated a PUFAs-synthase-specific PPTase in PKS system and provided a new strategy to improve the PUFA production in Thraustochytrids.

Optimizing Eicosapentaenoic Acid Production by Grafting a Heterologous Polyketide Synthase Pathway in the Thraustochytrid Aurantiochytrium.

Eicosapentaenoic acid (EPA) is an essential nutritional supplement for human health. The most prominent dietary source of EPA is fish oil, which is unsustainable because of the decline in fishery resources and serious environmental pollution. Alternatively, a heterologous polyketide synthase pathway for EPA biosynthesis was assembled in Thraustochytrid Aurantiochytrium. A 2A peptide-based facile assembly platform that can achieve multigene expression as a polycistron was first established. The platform was then applied to express the EPA biosynthetic gene cluster from Shewanella japonica in Aurantiochytrium. In the shake flask fermentation, the lipid and PUFA yields of the mutant were increased by 26.9 and 36.0%, respectively, and led to about 5-fold increase of the EPA yield. The final EPA titer reached 2.7 g/L in fed-batch fermentation. This study provides a novel metabolic engineering strategy to regulate the EPA ratio in microalgal oil for human nutritional supplementation.

GDNF enhances the anti-inflammatory effect of human adipose-derived mesenchymal stem cell-based therapy in renal interstitial fibrosis.

Adipose-derived mesenchymal stem cells (AMSCs) are a type of adult stem cell from the mesoderm with the capacity to migrate and differentiate into other cell lineages. As a morphogenetic state of stem cells, glial-derived neurotrophic factor (GDNF) has been found to promote cell proliferation and differentiation of stem cells. The aims of our study were to investigate the biological activity of AMSCs and whether the GDNF gene can enhance the anti-inflammatory properties of stem cells. In this study, stable proliferative GDNF-overexpressing AMSC lines were successfully established and the AMSCs/GDNF-AMSCs were cocultured with macrophages (Mφ) derived from THP-1 cells in a transwell system. The mRNA expression levels of tumor necrosis factor-alpha (TNF-α), inducible nitric oxide synthase (iNOS), interleukin (IL)-10 and IL-4 were detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). In addition, the expressions of CD163 and CD206, two markers of M2 macrophages, were detected with flow cytometric analysis. In animal experiments, AMSCs/GDNF-AMSCs (5 × 105) were administered to unilateral ureteral obstruction (UUO) nude mice for 3 or 7 days. The expression levels of cyclooxygenase-2 (COX-2), IL-6, transforming growth factor ß1 (TGF-ß1) and α-Smooth muscle actin (α-SMA) were determined by Western blotting. Renal pathological changes of all groups were observed by hematoxylin and eosin (HE) and Masson staining. In conclusion, in vitro cultured AMSCs induced a shift in macrophage phenotype from the inflammatory (M1) phenotype to the reparative (M2) phenotype. In the UUO model, AMSC treatment was conducive to the recovery of renal function and interstitial fibrosis. Therefore, we determined that AMSC therapy could promote the phenotypic transformation of macrophages and reduce the progression of renal fibrosis by suppressing inflammation. GDNF could enhance the anti-inflammatory effect of AMSCs.

Phytohormones as stimulators to improve arachidonic acid biosynthesis in Mortierella alpina.

Phytohormones are chemical messengers that have a positive effect at low concentrations on the biosynthesis of high-value compounds. Therefore, the effects of phytohormones on lipid and arachidonic acid (ARA) biosynthesis in Mortierella alpina were investigated in this study. At proper concentrations, the stimulatory effects of phytohormones on lipid production were determined to be as follows: 6-benzyl adenine (BA) > indole-3-acetic acid (IAA) > furfuryl adenine (KT) > gibberellin (GA) > indole-3-butyric acid (IBA) > abscisic acid (ABA). The results show that in the presence of 15 mg L-1 BA, the best positive effect was obtained, in which the lipid and ARA yields of M. alpina increased by 20.34% and 29.17%, respectively. Surprisingly, there was no synergy between the addition of two cytokinins (KT and BA), while adding cytokinins (KT or BA) and auxin (IAA) inhibited the growth of M. alpina and the ARA yield decreased by approximately 64%. Additional studies, such as those involving enzyme activity detection and quantitative real time polymerase chain reaction were carried out to check the fatty acid and lipid biosynthesis when the phytohormones were present. The activity of the main NADPH-supplying enzyme, 6-phosphoglucose dehydrogenase (G6PDH), increased by 19.52%. Moreover, the transcription levels of fatty acid synthase (FAS), Δ9-desaturase, and diacylglycerolacyltransferase (DGAT) increased by 9.3, 9.6 and 7.7 times, respectively, when only one type of phytohormone was present, indicating the enhancement of fatty acid and lipid biosynthesis in M. alpina. This study demonstrates the potential application of phytohormones for improving ARA yields of M. alpina.

Beraprost sodium mitigates renal interstitial fibrosis through repairing renal microvessels.

Beraprost sodium (BPS), as a prostacyclin analog, plays a significant role in various diseases based on its antiplatelet and vasodilation functions. However, its regulation and role in chronic kidney disease (CKD) still remain elusive. Here, we determined whether BPS could alleviate renal interstitial fibrosis, and improve the renal function and its therapeutic mechanism. In vitro, BPS increased angiogenesis in the HUVECs incubated with BPS detected by tube formation assay and repair damaged endothelial cell-cell junctions induced by hypoxia. In vivo, mice were randomly assigned to a sham-operation group (sham), a unilateral ureteral obstruction group (UUO), and a BPS intragastrical administration group (BPS), and sacrificed at days 3 and 7 post-surgery (six in each group). In UUO model, tissue hypoxia, renal inflammation, oxidative stress, and fibrotic lesions were detected by q-PCR and Western blot techniques and peritubular capillaries (PTCs) injury was detected by a novel technique of fluorescent microangiography (FMA) and analyzed by MATLAB software. Meanwhile, we identified cells undergoing endothelial cell-to-myofibroblast transition by the coexpression of endothelial cell (CD31) and myofibroblast (a-SMA) markers in the obstructed kidney. In contrast, BPS protected against interstitial fibrosis and substantially reduced the number of endothelial cell-to-myofibroblast transition cells. In conclusion, our data indicate the potent therapeutic of BPS in mitigating fibrosis through repairing renal microvessels and suppressing endothelial-mesenchymal transition (EndMT) progression after inhibiting inflammatory and oxidative stress effects. KEY MESSAGES: BPS could improve renal recovery through anti-inflammatory and anti-oxidative pathways. BPS could mitigate fibrosis through repairing renal microvessels and suppressing endothelial-mesenchymal transition (EndMT).

Transplantation of Amniotic Fluid-Derived Stem Cells Preconditioned with Glial Cell Line-Derived Neurotrophic Factor Gene Alleviates Renal Fibrosis.

Amniotic fluid-derived stem cells (AFSCs), which exhibit both embryonic and mesenchymal stem cell characteristics, have been shown to mitigate the degree of renal interstitial fibrosis. The aim of the present study was to determine whether transplantation of glial cell line-derived neurotrophic factor (GDNF)-modified AFSCs is more useful than transplantation of unmodified AFSCs for the treatment of renal interstitial fibrosis. Mice were randomly assigned to a sham-operation group (sham), a unilateral ureteral obstruction (UUO)-saline solution group (UUO), an AFSC transplantation group (AFSC) and a GDNF-modified AFSC transplantation group (GDNF-AFSC) and sacrificed at days 3 and 7 post-surgery (six in each group). We showed that GDNF-AFSCs noticeably suppressed oxidative stress and inflammation; additionally, GDNF-AFSCs positively regulated peritubular capillaries (PTCs), vascular endothelial growth factor (VEGF), hypoxia inducible factor-1α (HIF-1α), and transforming growth factor-ß1 (TGF-ß1) protein levels. Transmission electron microscopy (TEM) revealed that mitochondrial injury induced by the UUO model was significantly ameliorated after the mice were treated with GDNF-AFSCs. Therefore, we determined that GDNF gene promotes the abilities of AFSCs to inhibit inflammatory and oxidative stress effects, repair renal microvessels, relieve tissue hypoxia and mitochondrial damage, and, ultimately, alleviate renal interstitial fibrosis.

Adipose-Derived Mesenchymal Stem Cells: A New Tool for the Treatment of Renal Fibrosis.

As chronic kidney disease progresses, kidney tissue inevitably undergoes cell loss, accumulation of extracellular matrix, and kidney tissue fibrosis, eventually leading to end-stage renal disease. With the continuous innovation of cell therapy technology, mesenchymal stem cells are used in numerous fields, including cardiovascular diseases, diabetes, and kidney tissue injury repair. Adipose-derived mesenchymal stem cells (AMSCs), a type of pluripotent stem cells, have the potential for self-renewal and proliferation with low immunogenicity and significant anti-inflammatory properties. AMSCs can promote impaired cell regeneration and remodeling in renal lesions, thus avoiding further worsening of renal disease and even blocking or reversing the process of renal fibrosis. In this review, we discuss the mechanisms involved in the treatment of renal fibrosis with AMSCs and summarize the potential hazards that may exist in cell therapy.

The In Vitro Differentiation of GDNF Gene-Engineered Amniotic Fluid-Derived Stem Cells into Renal Tubular Epithelial-Like Cells.

Amniotic fluid is an alternative source of stem cells, and human amniotic fluid-derived stem cells (AFSCs) obtained from a small amount of amniotic fluid collected during the second trimester represent a novel source for use in regenerative medicine. These AFSCs are characterized by lower diversity, a higher proliferation rate, and a wider differentiation capability than adult mesenchymal stem cells. AFSCs are selected based on the cell surface marker c-kit receptor (CD117) using immunomagnetic sorting. Glial cell line-derived neurotrophic factor (GDNF) is expressed during early kidney development and regulates the proliferation and differentiation of stem cells in vitro. In this study, c-kit-sorted AFSCs were induced toward osteogenic or adipogenic differentiation. AFSCs engineered via the insertion of GDNF were cocultured with mouse renal tubular epithelial cells (mRTECs), which were preconditioned by hypoxia-reoxygenation in vitro. After coculture for 8 days, AFSCs differentiation into epithelial-like cells was evaluated by performing immunofluorescence, flow cytometry, and quantitative real-time polymerase chain reaction to identify cells expressing the renal epithelial markers, cytokeratin 18 (CK18), E-cadherin, aquaporin-1 (AQP1), and paired box 2 gene (Pax2). The GDNF gene enhanced AFSCs differentiation into RTECs. AFSCs possess self-renewal ability and multiple differentiation potential and thus represent a new source of stem cells.

Protective effect of GDNF-engineered amniotic fluid-derived stem cells on the renal ischaemia reperfusion injury in vitro.

OBJECTIVES: Amniotic fluid-derived stem cells (AFSCs) possessing multilineage differentiation potential are proposed as a novel and accessible source for cell-based therapy and tissue regeneration. Glial-derived neurotrophic factor (GDNF) has been hypothesized to promote the therapeutic effect of AFSCs on markedly ameliorating renal dysfunction. The aim of this study was to investigate whether AFSCs equipped with GDNF (GDNF-AFSCs) had capabilities of attenuating mouse renal tubular epithelial cells (mRTECs) apoptosis and evaluate its potential mechanisms. MATERIALS AND METHODS: A hypoxia-reoxygenation (H/R) model of the mRTECs was established. Injured mRTECs were co-cultured with GDNF-AFSCs in a transwell system. The mRNA expressions of hepatocytes growth factor (HGF) and fibroblast growth factor (bFGF) were detected by qRT-PCR. Changes of intracelluar reactive oxygen species (ROS) and the level of superoxide dismutase (SOD) and malondialdehyde (MDA) were examined. The expressions of nitrotyrosine, Gp91-phox, Bax, and Bcl-2 were determined by Western blotting. Cell apoptosis was assayed by flow cytometry, and caspase-3 activity was monitored by caspase-3 activity assay kit. RESULTS: Our study revealed that expression of growth factors was increased and oxidative stress was dramatically counteracted in GDNF-AFSCs-treated group. Furthermore, apoptosis induced by H/R injury was inhibited in mRTECs by GDNF-AFSCs. CONCLUSIONS: These data indicated that GDNF-AFSCs are beneficial to repairing damaged mRTECs significantly in vitro, which suggests GDNF-AFSCs provide new hopes of innovative interventions in different kidney disease.