Maternal undernourished fetal kidneys exhibit differential regulation of nephrogenic genes including downregulation of the Notch signaling pathway

Consequences of Exposure to Famine Exposure on the Later Life eGFR Decline Among Survivors of the Great Chinese Famine: A Retrospective Study

OBJECTIVES

Chronic kidney disease (CKD) significantly contributes to the socio-economic burden both in China and worldwide. Previous research has shown that experiencing childhood famine is linked to various chronic conditions like diabetes, hypertension, and proteinuria. However, the long-term effects of early-life famine exposure on adult kidney function remain unclear. This study investigates whether exposure to the Chinese Great Famine (1959-1962) is associated with a decline in glomerular filtration rate (GFR) later in life.

DESIGN AND METHODS

China Health and Retirement Longitudinal Study is a population-based observational study. We analyzed data from 8,828 participants in the 2011-2012 baseline survey, updated in 2014. Participants were categorized based on their birth year into fetal-exposed (1959-1962), childhood-exposed (1949-1958), adolescence/adult-exposed (1912-1948), and nonexposed (1963-1989) groups. The estimated GFR (eGFR) was calculated using the CKD-EPI-Cr-Cys equation (2021), with CKD defined as an eGFR below 60 mL/min/1.73 m2.

RESULTS

Average eGFR values were 103.0, 96.8, 91.2, and 76.3 mL/min/1.73 m2 for the fetal-exposed, childhood-exposed, adolescence/adult-exposed, and nonexposed groups, respectively. The eGFR in the exposed groups was significantly lower compared to the nonexposed group. Specifically, famine exposure correlated with a lower eGFR (coefficient estimates [CE] -9.14, 95% confidence interval [CI] -9.46, -8.82), with the strongest association observed in the adolescence/adult-exposed group (CE -26.74, 95% CI -27.75, -25.74). Adjusting for variables such as demographics, physical and laboratory tests, complications, and personal habits like smoking and drinking did not qualitatively alter this association (CE -1.38, 95% CI -1.72, -1.04). Further stratification by sex, body mass index, alcohol consumption history, hypertension, diabetes, Center for Epidemiologic Studies Depression score, and education level showed that the association remained consistent.

CONCLUSIONS

Exposure to famine during different life stages can have enduring effects on GFR decline in humans.

Maternal protein deficiency alters primary cilia length in renal tubular and impairs kidney development in fetal rat

Introduction

Intrauterine malnutrition impairs embryo kidney development and leads to kidney disease and hypertension in adulthood, yet the underlying mechanism remains unclear.

Methods

With a maternal protein restriction (MPR) rat model, we investigated the critical ciliogenesis factors and β-catenin pathway in FGR fetal kidneys and analyzed the impact of aberrant primary cilia on renal tubular epithelium.

Results

The data showed decreased nephron number and renal tubular dysgenesis in FGR fetus. FGR fetus showed deregulated expression of ciliogenesis factors including upregulation of IFT88 and downregulation of DYNLT1, accompanied with cilia elongation in renal tubular epithelial cells. Wnt7b, the key ligand for Wnt/β-catenin signaling, was downregulated and nuclear translocation of β-catenin was decreased. The proapoptotic protein was upregulated. In vitro study with HK-2 cells showed that overexpression of IFT88 lengthened the cilia, inhibited β-catenin signaling. Besides, IFT88 overexpression suppressed cell proliferation, activated autophagy, and induced cell apoptosis. Inhibition of autophagy partly restored the cilia length and cell viability. Likewise, knockdown of DYNLT1 led to cilia elongation, suppressed cell proliferation, and promoted apoptosis in HK-2 cell. However, the cilia elongation induced by DYNLT1 knockdown was not autophagy-dependent, but associated with reactive oxygen species (ROS) accumulation.

Discussion

We elucidated that intrauterine protein malnutrition led to deregulation of ciliogenesis factors and cilia elongation in renal tubular epithelial, inhibited β-catenin signaling, and induced cell apoptosis and ultimately, compromised kidney development.

LncRNA00492 is required for marginal zone B-cell development

B-cell development undergoes a series of steps from the bone marrow to the secondary lymphoid organs. A defect in B-cell development can lead to immunodeficiency or malignant disorders, such as leukaemia or lymphoma. Long non-coding RNAs have been reported to act as important regulators of many pathological processes. However, very little is known regarding the role of lncRNAs during B-cell development and the regulation of their expression. In this study, we explored the expression and role of lncRNA Gme00492 in B-cell development. We observed that lnc00492 was highly expressed in B-cell development and primarily expressed in the nucleus. Lnc00492-deficient mice had fewer marginal zone B cells in the spleen, likely due to a developmental block. Importantly, lnc00492 interacts with CTBP1 and targets it for ubiquitination and degradation during B-cell development, whereas the transcriptional corepressor factor CTBP1 plays a critical role in Notch2 signalling. Thus, we identified a novel regulatory axis between lnc00492 and CTBP1 in B cells, suggesting that lnc00492 is essential for marginal zone B-cell development.

Economic Status Moderates the Association Between Early-Life Famine Exposure and Hyperuricemia in Adulthood

CONTEXT

The double burden of malnutrition (DBM), undernutrition in early life and an obesogenic environment later on, influences later risk of chronic disorders. The Great Famine in China from 1959 to1962 and remarkable economic development from the 1980s provided such a burden for a large number of people in their 60s.

OBJECTIVE

We aimed to analyze the effect of economic status on the association between famine exposure in early life and hyperuricemia in adulthood.

DESIGN AND SETTING

Participants numbering 12 666 were enrolled in China based on the Survey on Prevalence in East China for Metabolic Diseases and Risk Factors (SPECT-China) Study from 2014 to 2016.

PARTICIPANTS

Participants with fetal or childhood famine exposure (birth year 1949-1962) formed the exposure group.

MAIN OUTCOME MEASURE

Hyperuricemia was defined as uric acid (UA) > 420 μmol/L for men and > 360 μmol/L for women. The association of famine with hyperuricemia was assessed via regression analyses.

RESULTS

Early-life famine exposure was negatively associated with UA levels (P = .045) but was not associated with hyperuricemia (P = .226) in the whole study population. Economic status could moderate the association of famine exposure with UA and hyperuricemia (P ≤ .001). In participants with high economic status, early-life famine exposure was positively associated with UA levels (unstandardized coefficients 7.61, 95% CI 3.63-11.59, P < .001), and with hyperuricemia (odds ratio 1.47, 95% CI 1.19-1.81, P < .001).

CONCLUSIONS

Economic status could moderate the association between exposure to famine in early life and hyperuricemia in adulthood, indicating that the DBM might affect hyperuricemia in an opposite direction of the effects of undernutrition in early life alone.

Study of the aqueous extract of Aloe vera and its two active components on the Wnt/β-catenin and Notch signaling pathways in colorectal cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Aloe vera (L.) Burm. f. (Aloe vera) is a common Traditional Chinese Medicine (TCM) recorded in Pharmacopoeia of the People's Republic of China (version 2015). It has been traditionally used for treatment of constipation. Aloe vera requires much attention for its safety evaluation because several studies have reported the association between oral consumption of Aloe vera and the development of colorectal cancer (CRC). However the material basis and molecular mechanism are.still less well elucidated. Although Wnt/β-catenin and Notch signaling pathway have been known to be closely related to the initiation and development of CRC, the impacts of Aloe vera on these cancerous pathways have not been completely determined yet.

AIM OF THIS STUDY

Hence, this study aimed to study the impacts of Aloe vera on the Wnt/β-catenin and Notch signaling pathway, as well as proliferation of CRC cells.

MATERIALS AND METHODS

Firstly, the effects of Aloe vera aqueous extract and its two active components (aloin and aloesin) on the Wnt/β-catenin and Notch signaling pathway were studied by luciferase reporter, RT-qPCR, western blotting and immunofluorescence assays, respectively. Furthermore, RNA sequencing analysis (RNA-seq) was then performed to verify their regulatory activities on the Wnt-related and Notch-related genes expression. Finally, their impacts on RKO cell proliferation and cell cycle phase were also evaluated via MTT assay and cell cycle analysis.

RESULTS

Our results indicate that the aqueous extract of Aloe vera and its active component aloin activated the Wnt/β-catenin pathway and inhibited the Notch signaling pathway only in the presence of Wnt3a. While aloesin was characterized to directly activate the Wnt/β-catenin pathway and inhibit the Notch pathway independent of Wnt3a. Within 24h, the Aloe vera extract and its two components were failed to affect the proliferation or cell cycle phase of RKO cells. Nevertheless, in the presence of Wnt3a, the aqueous extract of Aloe vera with the concentration of 33.3 μg/ml start to promote the cell proliferation of RKO cells after 48h incubation.

CONCLUSION

In conclusion, this study showed that Aloe vera extract and its active component aloin activated the Wnt/β-catenin pathway and inhibited the Notch pathway in the presence of Wnt3a. While another active component, aloesin, activated the Wnt/β-catenin pathway and inhibited the Notch signaling pathway independent of Wnt3a. Given that Wnt/β-catenin and Notch pathway are closely associated with the progression of CRC, these findings would be helpful to better understand the colonic carcinogenicity of Aloe vera.

Exposure to famine in early life and chronic kidney diseases in adulthood

Objective

Chronic kidney disease (CKD) is an increasing contributor to the global disease burden. Previous findings indicated that exposure to famine in early life was associated with various metabolic diseases and urinary protein levels. We aimed to assess whether the exposure to China’s Great Famine 1959–1962 during fetal or childhood period was associated with glomerular filtration rate (GFR) and risk of CKD (eGFR<60 mL/min per 1.73 m²) in adulthood.

Materials and methods

SPECT-China was a population-based observational study in 2014–2015. Totally, 5124 women were included from SPECT-China study. Based on the birth year, they were divided into fetal-exposed (1959–1962), childhood-exposed (1949–1958), adolescence/young adult-exposed (1921–1948), and non-exposed (1963–1974, reference). The estimated glomerular filtration rate (eGFR) was calculated according to the Chronic Kidney Disease Epidemiology Collaboration equation. CKD was defined as eGFR less than 60 mL/min per 1.73 m².

Results

Compared with the non-exposed, fetal exposure to famine was significantly associated with lower eGFR (B −1.47, 95%CI −2.81, −1.13) and greater risk of having CKD (OR 2.85, 95%CI 1.25, 6.50) in the crude model adjusting age. Further adjustments for demographic variables, body mass index, diabetes, and blood pressure did not qualitatively change the association (eGFR B −1.35, 95%CI −2.67, −0.04; CKD OR 2.42, 95%CI 1.05, 5.58). This association was not found in childhood-exposed and adolescence/young adult-exposed individuals.

Conclusions

Prenatal exposure to famine may have long-term effects on declined GFR and the development of CKD in humans. thus, fetal stage may be an important time window to prevent CKD in later life.

Understanding the role of maternal diet on kidney development; an opportunity to improve cardiovascular and renal health for future generations

The leading causes of mortality and morbidity worldwide are cardiovascular disease (high blood pressure, high cholesterol and renal disease), cancer and diabetes. It is increasingly obvious that the development of these diseases encompasses complex interactions between adult lifestyle and genetic predisposition. Maternal malnutrition can influence the fetal and early life environment and pose a risk factor for the future development of adult diseases, most likely due to impaired organogenesis in the developing offspring. This then predisposes these offspring to cardiovascular disease and renal dysfunction in adulthood. Studies in experimental animals have further illustrated the significant impact maternal diet has on offspring health. Many studies report changes in kidney structure (a reduction in the number of nephrons in the kidney) in offspring of protein-deprived dams. Although the early studies suggested that increased blood pressure was also present in offspring of protein-restricted dams, this is not a universal finding and requires clarification. Importantly, to date, the literature offers little to no understanding of when in development these changes in kidney development occur, nor are the cellular and molecular mechanisms that drive these changes well characterised. Moreover, the mechanisms linking maternal nutrition and a suboptimal renal phenotype in offspring are yet to be discerned—one potential mechanism involves epigenetics. This review will focus on recent information on potential mechanisms by which maternal nutrition (focusing on malnutrition due to protein restriction, micronutrient restriction and excessive fat intake) influences kidney development and thereby function in later life.

Maternal undernutrition upregulates apoptosis in offspring nephrogenesis

Maternal undernutrition (MUN) results in growth-restricted newborns with reduced nephron numbers that is associated with increased risk of hypertension and renal disease. The total adult complement of nephrons is set during nephrogenesis suggesting that MUN affects the staged development of nephrons in as yet unknown manner. A possible cause may be the increased renal apoptosis; therefore, we investigated whether apoptotic signaling and cell death were increased in MUN rat kidneys. Pregnant rat dams were fed an ad libitum diet [control] or were 50% food restricted (MUN) starting at embryonic day (E) 10. Male offspring kidneys (n = 5 each, MUN and control) were analyzed for mRNA using quantitative PCR (E20) and for protein expression using Western blotting and immunohistochemistry (E20 and postnatal day 1, P1). Apoptosis was measured by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Upregulation of pro-apoptotic protein expression was detected at E20 (Fas receptor, caspase 9) and at P1 (caspase 3, Bax). The anti-apoptotic factor Bcl2 was significantly decreased in P1 kidneys. Kidney TUNEL showed apoptotic nuclei significantly increased in the P1 nephrogenic zone (MUN 3.3 + 0.3 v. C 1.6 + 0.5, P = 0.002). The majority of apoptotic nuclei co-localized to mesenchyme and pretubular aggregates in the nephrogenic zone. Differential regulation of apoptosis in mesenchyme and pretubular aggregates following parturition suggests a mechanism for nephropenia in gestational programming of the kidney.

Gestational diabetes mellitus alters apoptotic and inflammatory gene expression of trophobasts from human term placenta

AIM

Increased placental growth secondary to reduced apoptosis may contribute to the development of macrosomia in GDM pregnancies. We hypothesize that reduced apoptosis in GDM placentas is caused by dysregulation of apoptosis related genes from death receptors or mitochondrial pathway or both to enhance placental growth in GDM pregnancies.

METHODS

Newborn and placental weights from women with no pregnancy complications (controls; N=5), or with GDM (N=5) were recorded. Placental villi from both groups were either fixed for TUNEL assay, or snap frozen for gene expression analysis by apoptosis PCR microarrays and qPCR.

RESULTS

Maternal, placental and newborn weights were significantly higher in the GDM group vs. Controls. Apoptotic index of placentas from the GDM group was markedly lower than the Controls. At a significant threshold of 1.5, seven genes (BCL10, BIRC6, BIRC7, CASP5, CASP8P2, CFLAR, and FAS) were down regulated, and 13 genes (BCL2, BCL2L1, BCL2L11, CASP4, DAPK1, IκBκE, MCL1, NFκBIZ, NOD1, PEA15, TNF, TNFRSF25, and XIAP) were unregulated in the GDM placentas. qPCR confirmed the consistency of the PCR microarray. Using Western blotting we found significantly decreased placental pro-apoptotic FAS receptor and FAS ligand (FASL), and increased mitochondrial anti-apoptotic BCL2 post GDM insult. Notably, caspase-3, which plays a central role in the execution-phase of apoptosis, and its substrate poly (ADP-ribose) polymerase (PARP) were significantly down regulated in GDM placentas, as compared to non-diabetic Control placentas.

CONCLUSION

Maternal GDM results in heavier placentas with aberrant placental apoptotic and inflammatory gene expression that may account, at least partially, for macrosomia in newborns.

Ethnic differences in the accumulation of fat and lean mass in late gestation

OBJECTIVES

Lower birth weight within the normal range predicts adult chronic diseases, but the same birth weight in different ethnic groups may reflect different patterns of tissue development. Neonatal body composition was investigated among non-Hispanic Caucasians and African Americans, taking advantage of variability in gestational duration to understand growth during late gestation.

METHODS

Air displacement plethysmography assessed fat and lean body mass among 220 non-Hispanic Caucasian and 93 non-Hispanic African American neonates. The two ethnic groups were compared using linear regression.

RESULTS

At 36 weeks of gestation, the average lean mass of Caucasian neonates was 2,515 g vs. that of 2,319 g of African American neonates (difference, P = 0.02). The corresponding figures for fat mass were 231 and 278 g, respectively (difference, P = 0.24). At 41 weeks, the Caucasians were 319 g heavier in lean body mass (P < 0.001) but were also 123 g heavier in fat mass (P = 0.001). The slopes for lean mass vs. gestational week were similar, but the slope of fat mass was 5.8 times greater (P = 0.009) for Caucasian (41.0 g/week) than for African American neonates (7.0 g/week).

CONCLUSIONS

By 36 weeks of gestation, the African American fetus developed similar fat mass and less lean mass compared with the Caucasian fetus. Thereafter, changes in lean mass among the African American fetus with increasing gestational age at birth were similar to the Caucasian fetus, but fat accumulated more slowly. We hypothesize that different ethnic fetal growth strategies involving body composition may contribute to ethnic health disparities in later life.