Biology subjects

Adjaye, J.

Publications and source records attributed to Adjaye, J..

29 records · Page 2Linked to original sources

bioRxiv2022

JNK signalling regulates self-renewal of proliferative urine-derived renal progenitor cells via inhibition of ferroptosis

With a global increase in chronic kidney disease patients, alternatives to dialysis and organ transplantation are needed. Stem cell-based therapies could be one possibility to treat chronic kidney disease. Here, we used multipotent urine-derived renal progenitor cells (UdRPCs) to study nephrogenesis. UdRPCs treated with the JNK inhibitor-AEG3482, displayed decreased proliferation and downregulated transcription of cell cycle-associated genes as well as the kidney progenitor markers -SIX2, CITED1, and SALL1. In addition, levels of activated SMAD2/3, which is associated with the maintenance of self-renewal in UdRPCs, were decreased. JNK inhibition resulted in less efficient oxidative phosphorylation and more lipid peroxidation via ferroptosis-an iron-dependent non-apoptotic cell death pathway linked to various forms of kidney disease. Our study reveals the importance of JNK signalling in maintaining self-renewal as well as protection against ferroptosis in SIX2-positive UdRPCs. We propose that UdRPCs can be used for modelling ferroptosis-induced kidney diseases.

cell biology↗

bioRxiv2022

Derivation of the immortalized cell line-UM51-PrePodo-hTERT and its responsiveness to Angiotensin II and activation of RAAS

Recent demographic studies predict there will be a considerable increase of elderly people within the next decades. Aging has been recognized as one of the main risk factors of the worlds most prevalent diseases, including neurodegenerative disorders, cancer, cardiovascular disease, and metabolic disease. During the process of aging a gradual loss of tissue volume and organ function is observed, which is partially caused by replicative senescence. The capacity of cellular proliferation and replicative senescence is tightly regulated by their telomere length. When the telomere length with progressive cell division is critically shortened, the cell becomes proliferative arrested and DNA damage response and cellular senescence are triggered. At this time point the so called "Hayflick limit" is attained. Podocytes are a cell type that is found in the kidney glomerulus where they have major implications in blood filtration. Mature podocytes are terminal differentiated cells that are unable to undergo cell division in vivo. For this reason, the establishment of podocyte cell cultures has been very challenging. In our present study, we present the successful immortalization of a human podocyte progenitor cell line, of which the primary cell cells were isolated directly from the urine of a 51-year-old male. The immortalized cell line has been cultured over the course of one year ([~]100 passages) with high proliferation capacity, while still endowed with contact inhibition and P53 expression and activation. Furthermore, by immunofluorescent-based expression and quantitative Real-Time PCR for the podocyte markers NPHS1, SYNPO and WT1 we confirmed the differentiation capacity of the immortalized cells. Finally, we evaluated and confirmed the responsiveness of the immortalized cells on the main mediator Angiotensin II (ANGII) of the renin-angiotensin-system (RAS). Elevated levels of ANGII have been identified as a main risk factor for the initiation and progression of chronic kidney disease (CKD). CKD is characterized by an impairment of podocyte function and subsequently podocyte apoptosis. As a major risk factor for patients to develop CKD, diabetes, hypertension, heart disease and stroke have been recognized - all of which show increased incidence in elderly people. In conclusion, we have shown that it is possible to by-pass cellular replicative senescence (Hayflicks limit) by TERT-driven immortalization of human urine-derived pre-podocyte cells from a 51-year-old African male.

cell biology↗

bioRxiv2022

Crosstalk between age accumulated DNA-damage and the SIRT1-AKT-GSK3b axis in urine derived renal progenitor cells

The aging process is manifested by a multitude of interlinked biological processes. These processes contribute to genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient-sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication. Together these are recognized as of the main risk factors of the worlds most prevalent diseases, such as neurodegenerative disorders, cancer, cardiovascular disease, and metabolic disease. The mammalian ortholog of the yeast silent information regulator (Sir2) SIRT1 is a NAD+-dependent class III histone deacetylase and has been recognized to be involved in many of the forementioned processes. Therefore, its activity is connected to aging via the regulation of apoptosis, cell differentiation, development, stress response, metabolism, and tumorigenesis. Furthermore, the physiological activity of several sirtuin family members has been connected to the regulation of life span of lower organisms (Caenorhabditis elegans and Drosophila melanogaster) as well as mammals. Aging in somatic cells of mammals is accompanied by mutations and other forms of DNA damage. These might manifest in transient cell cycle arrest associated with DNA repair, apoptosis, senescence, or cell differentiation. The activity of SIRT1 has previously been reported to be regulated by the DNA damage response pathway. On the one hand, SIRT1 is recruited from ATM to DBS and is required for DNA damage repair, but on the other hand, SIRT1 activity was also found to be negatively regulated by genotoxic stress via the interaction of ATM with Deleted in Breast Cancer 1 (DBC1). Increased levels of DBS are associated with downregulation of ATM and lower phosphorylation levels of AKT and GSK3{beta}, with significant implications for mesenchymal stem cell (MSC) maintenance and differentiation. In this proposed "stem cell checkpoint," the ATM signalling pathway initiated by DBS maintains MSCs and blocks their differentiation. Based on this, it has already been established that in senescent mesenchymal stem cells, SIRT1 expression is decreased, while its overexpression delays the onset of senescence and loss of differentiation capacity/ability. In the present study, we provide evidence that SIX2-positive urine derived renal progenitor cells-UdRPCs isolated directly from human urine show typical hallmarks of aging when obtained from elderly donors. This includes the transcriptional downregulation of SIRT1 and its downstream targets AKT and GSK3{beta}. This transcriptional downregulation is accompanied by an increase in DNA damage and transcriptional levels several cell cycle inhibitors such as P16, reflecting possibly the ATM induced "stemness checkpoint" to maintain UdRPC stemness and differentiation capacity. We provide evidence that the renal progenitor transcription factor SIX2 binds to the coding sequence of SIRT1 and both factors mutually influence the transcription of each other. Furthermore, we show that the SIRT1 promoter region is methylation sensitive and becomes subsequently methylated in UdRPCs derived from aged donors, dividing them into SIRT1 high and low expressing UdRPCs. This downregulation might render the cells more vulnerable to endogenous noxae accelerating the accumulation of DNA damage and ultimately the accumulation of aging associated hallmarks.

cell biology↗

bioRxiv2021

Inflammation and Cellular Stress Induced Neurological Sequelae of Plasmodium falciparum Malaria

BackgroundMalaria caused by Plasmodium falciparum results in severe complications including cerebral malaria (CM) especially in children. While the majority of falciparum malaria survivors make a full recovery, there are reports of some patients ending up with neurological sequelae. MethodsWe performed an analysis of pooled transcriptome data of whole blood samples derived from two studies involving various Plasmodium falciparum infections, comprising mild malaria (MM), non-cerebral severe malaria (NCM) and CM. Pathways and gene ontologies (GOs) elevated in the distinct falciparum infections were identified. ResultsContrary to other research findings, our analysis showed MM share similar biological processes with cancer and neurodegenerative diseases, NCM is associated with drug resistance and glutathione metabolism and CM is correlated with endocannabinoid signaling and non-alcoholic fatty liver disease (NAFLD). GO revealed the terms biogenesis, DNA damage response and IL-10 production in MM, down-regulation of cytoskeletal organization and amyloid-beta clearance in NCM and aberrant signaling, neutrophil degranulation and gene repression in CM. Differential gene expression analysis between CM and NCM showed the up-regulation of neutrophil activation and response to herbicides while regulation of axon diameter was down-regulated in CM. ConclusionsThe results of this study have demonstrated that the deleterious effect of falciparum malaria on the brain may not be limited to CM and NCM alone but also MM. However, the severity of neurological deficit in CM might be due to the down-regulation of various genes involved in cellular function through transcriptional repression, axonal dysfunction, dysregulation of signaling pathways and neurodegeneration as a result of inflammation and cellular stress. We anticipate that our data might form the basis for future hypothesis-driven malaria research.

molecular biology↗

bioRxiv2021

Investigation of Thyroid Hormone Associated Gene-Regulatory Networks during Hepatogenesis using an Induced Pluripotent Stem Cell based Model

Currently, the only treatment of end-stage liver diseases is liver transplantation. The worldwide shortage of donor organs and the high number of patients suffering from end-stage liver diseases, require alternative treatment approaches. Therefore, the generation of hepatocyte-like cells (HLCs) derived from induced pluripotent stem cells (iPSCs) is a promising treatment option. HLCs are suitable for patient-specific drug screening, disease modeling and regenerative medicine. So far, they are immature and resemble the fetal state. In this study, we employed the combined thyroid hormones triiodo-L-thyronine (T3) and L-thyroxine (T4) to drive HLCs towards maturation. HLCs expressed the maturation markers ALBUMIN (ALB), ALPHA-1 ANTITRYPSIN (A1AT), CYTOCHROME P450 3A4 (CYP3A4) and TRANSTHYRETIN (TTR). Remarkably, stimulation with T3 and T4 slightly reduced the expression of the fetal marker CYTOCHROME P450 3A7 (CYP3A7) and had an even more pronounced effect on ALPHA-FETOPROTEIN (AFP) levels. Comparative transcriptome and associated pathways in unstimulated and T3 and T4 stimulated HLCs revealed regulated expression of numerous genes within for example the peroxisome proliferator-activated receptor (PPAR), transforming growth factor beta (TGF-{beta}), mitogen-activated protein kinase/extracellular-signal-regulated kinase (MAPK/ERK) signaling pathways and thyroid hormone synthesis. We propose the inclusion of combined T3 andT4 in HLC differentiation protocols to enhance maturation and therefore provide additional improvement in their applications in drug screening and disease modeling.

developmental biology↗

bioRxiv2021

Angiotensin II disrupts the cytoskeletal architecture of human urine-derived podocytes and results in activation of the renin-angiotensin system

High blood pressure is one of the major public health problems which causes severe disorders in several tissues including the human kidney. One of the most important signaling pathways associated with the regulation of blood pressure is the renin-angiotensin system (RAS), with its main mediator angiotensin II (ANGII). Elevated levels of circulating and intracellular ANGII and aldosterone lead to pro-fibrotic, -inflammatory and -hypertrophic milieu that causes remodelling and dysfunction in cardiovascular and renal tissues. Furthermore, ANGII has been recognized as major risk factor for the induction of apoptosis in podocytes, ultimately leading to chronic kidney disease (CDK). In the past, disease modeling of kidney-associated malignancies was extremely difficult, as the derivation of kidney originated cells is very challenging. Here we describe a differentiation protocol for reproducible differentiation of SIX2-positive urine derived renal progenitor cells (UdRPCs) into mature podocytes bearing typical foot processes. The UdRPCs-derived podocytes show the ability to execute Albumin endocytosis and the activation of the renin-angiotensin system by being responsive to ANGII stimulation. Our data reveals the ANGII dependent downregulation of NPHS1 and SYNPO, resulting in the disruption of the complex podocyte cytoskeletal architecture, as shown by immunofluorescence-based detection of -ACTININ. In the present manuscript we confirm and propose UdRPCs as a unique cell type useful for studying nephrogenesis and associated diseases. Furthermore, the responsiveness of UdRPCs-derived podocytes to ANGII implies potential applications in nephrotoxicity studies and drug screening.

cell biology↗

bioRxiv2020

Transmission of SARS-COV-2 from China to Europe and West Africa: a detailed phylogenetic analysis.

BackgroundSARS-CoV-2, the virus causing the Covid-19 pandemic emerged in December 2019 in China and raised fears that it could overwhelm healthcare systems worldwide. In June 2020, all African countries registered human infections with SARS-CoV-2. The virus is mutating steadily and this is monitored by a well curated database of viral nucleotide sequences from samples taken from infected individual thus enabling phylogenetic analysis and phenotypic associations. MethodsWe downloaded from the GISAID database, SARS-CoV-2 sequences established from four West African countries Ghana, Gambia, Senegal and Nigeria and then performed phylogenetic analysis employing the nextstrain pipeline. Based on mutations found within the sequences we calculated and visualized statistics characterizing clades according to the GISAID nomenclature. ResultsWe found country-specific patterns of viral clades: the later Europe-associated G-clades predominantly in Senegal and Gambia, and combinations of the earlier (L, S, V) and later clades in Ghana and Nigeria. Contrary to our expectations, the later Europe-associated G-clades emerged before the earlier clades. Detailed analysis of distinct samples showed that some of the earlier clades might have circulated latently and some reflect migration routes via Mali and Tunisia. ConclusionsThe distinct patterns of viral clades in the West African countries point at its emergence from Europe and China via Asia and Europe. The observation that the later clades emerged before the earlier clades could be simply due to founder effects or due to latent circulation of the earlier clades. Only a marginal correlation of the G-clades associated with the D614G mutation could be identified with the relatively low case fatality (0.6-3.2). Key messagesO_LIGhana and Nigeria have a combination of earlier (L, V, S) and later Europe-associated G-clades of SARS-CoV-2, therefore pointing to multiple introductions while in Senegal and Gambia Europe-associated G-clades predominate pointing to introductions mainly from Europe. C_LIO_LISurprisingly, the later G-clades emerged before the earlier clades (L, V, S) C_LIO_LIDetailed phylogenetic analysis points at latent circulation of earlier clades before the first registered cases. C_LIO_LIPhylogenetic analysis of some cases points at migration routes to Europe via Tunisia, Egypt and Mali. C_LIO_LIA marginal correlation of r=0.28 between the percentage of the D614G mutation defining the G-clades and case-fatality can be detected. C_LI

molecular biology↗

bioRxiv2020

Impaired p53-mediated DNA damage response contributes to microcephaly in Nijmegen Breakage Syndrome patient-derived cerebral organoids

Nijmegen Breakage Syndrome (NBS) is a rare autosomal recessive genetic disorder caused by mutations within NBN, a DNA-damage repair protein. Hallmarks of NBS include several clinical manifestations such growth retardation, chromosomal instability, immunodeficiency and progressive microcephaly. However, the etiology of microcephaly in NBS patients remains elusive. Here, we employed induced pluripotent stem cell-derived brain organoids from two NBS patients to analyze the underlying mechanisms of microcephaly. We show that NBS-organoids carrying the homozygous 647del5 NBN mutation are significantly smaller in size with disrupted cyto-architecture Patient-derived organoids exhibit premature differentiation together with neuronatin (NNAT) overexpression and key pathways related to DNA damage response and cell cycle are differentially regulated compared to controls. Moreover, we show that after exposure to bleomycin, NBS organoids undergo a delayed p53-mediated DNA damage response and aberrant trans-synaptic signalling, which ultimately leads to neuronal apoptosis. Our data provide insights into how mutations within NBN alters neurogenesis in NBS patients, thus providing a proof of concept that cerebral organoids are a valuable tool for studying DNA damage-related disorders.

neuroscience↗

bioRxiv2020

Meta-analysis of transcriptomes of SARS-Cov2 infected human lung epithelial cells identifies transmembrane serine proteases co-expressed with ACE2 and biological processes related to viral entry, immunity, inflammation and cellular stress.

The COVID-19 pandemic resulting from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which emerged in December 2019 in the Chinese city of Wuhan in the province Hubei has placed immense burden on national economies and global health. At present neither vaccination nor therapies are available although several antiviral agents such as remdesivir, originally an Ebola drug, nelfinavir, an HIV-1 protease inhibitor and other drugs such as lopinavir have been evaluated. Here, we performed a meta-analysis of RNA-sequencing data from three studies employing human lung epithelial cells. Of these one focused on lung epithelial cells infected with SARS-CoV-2. We aimed at identifying genes co-expressed with angiotensin I converting enzyme 2 (ACE2) the human cell entry receptor of SARS-CoV-2, and unveiled several genes correlated or inversely correlated with high significance, among the most significant of these was the transmembrane serine protease 4 (TMPRSS4). Serine proteases are known to be involved in the infection process by priming the virus spike protein. Pathway analysis revealed papilloma virus infection amongst the most significantly correlated pathways. Gene Ontologies revealed regulation of viral life cycle, immune responses, pro-inflammatory responses-several interleukins such as IL6, IL1, IL20 and IL33, IFI16 regulating the interferon response to a virus, chemo-attraction of macrophages, last and not least cellular stress resulting from activated Reactive Oxygen Species. We believe that this dataset will aid in a better understanding of the molecular mechanism(s) underlying COVID-19.

molecular biology↗

bioRxiv2019

IPSC-derived neuronal cultures expressing the Alzheimer’s disease associated rare TREM2 R47H variant enables the construction of an Aβ-induced gene regulatory network

Recently, genes associated with immune response and inflammation have been identified as genetic risk factors for late-onset Alzheimers disease (LOAD). One of them is the rare p.Arg47His (R47H) variant within triggering receptor expressed on myeloid cells 2 (TREM2), which has been shown to increase the risk for developing AD 2-3-fold. Here, we report the generation and characterization of a model of LOAD using lymphoblast-derived iPSCs from patients harbouring the R47H mutation in TREM2 (AD TREM2 iPSCs), as well as from control individuals without dementia (CON iPSCs). iPSCs efficiently differentiate into mature neuronal cultures and comparative global transcriptome analysis identified a distinct gene expression profile in AD TREM2 neuronal cultures. Furthermore, manipulation of the iPSC-derived functional neuronal cultures with an A{beta}-S8C dimer highlighted metabolic pathways, phagosome and immune response as the most perturbed pathways in AD TREM2 neuronal cultures. Through the construction of an A{beta}-induced gene regulatory network, we were able to identify an A{beta} signature linked to protein processing in the endoplasmic reticulum (ER) which emphasised ER-stress, as a potential causal role in LOAD. Overall, this study has shown that our AD-iPSC based model can be used for in-depth studies to better understand the molecular mechanisms underlying the etiology of LOAD and provides new opportunities for screening of potential therapeutic targets.

neuroscience↗

bioRxiv2019

A Comprehensive Molecular Portrait of Human Urine-derived Renal Progenitor Cells

BackgroundHuman urine is now recognised as a non-invasive source of stem cells with regeneration potential. These cells are mesenchymal stem cells but their detailed molecular and cellular identities are poorly defined. Furthermore, unlike the mouse, the gene regulatory network driving self-renewal and differentiation into functional renal cells in vitro remain unresolved.\n\nMethodsWe isolated urine stem cells from 10 individuals from both genders and distinct ages, characterized them as renal progenitor cells and explored the gene regulatory network sustaining self-renewal.\n\nResultsThese cells express pluripotency-associated proteins-TRA-1-60, TRA-1-81, SSEA4, C-KIT and CD133. Expression of pluripotency-associated proteins enabled rapid reprogramming into iPSCs using episomal-based plasmids without pathway perturbations. Transcriptome analysis revealed expression of a plethora of nephrogenesis-related genes such as SIX2, OSR1, CITED1, NPHS2, NPHS1, PAX2, SALL1, AQP2, EYA1, SLC12A1 and UMOD. As expected, the cells transport Albumin by endocytosis. Based on this, we refer to these cells as urine derived renal progenitor cells-UdRPCs. Associated GO-term analysis of UdRPCs and UdRPC-iPSCs underlined their renal identity and functionality. Upon differentiation by WNT activation using the GSK3{beta}-inhibitor (CHIR99021), transcriptome and KEGG pathway analysis revealed upregulation of WNT-associated genes-AXIN2, JUN and NKD1. Protein interaction network identified JUN- a downstream target of the WNT pathway in association with STAT3, ATF2 and MAPK1 as a putative regulator of self-renewal and differentiation in UdRPCs. Furthermore, like pluripotent stem cells, self-renewal is maintained by FGF2-driven TGF{beta}-SMAD2/3 pathway.\n\nConclusionThis in vitro model and the data presented should lay the foundation for studying nephrogenesis in man.\n\nSignificance StatementHuman urine is a non-invasive source of stem cells with regeneration potential. Here, we investigated the cellular and molecular identities, and the gene regulation driving self-renewal and differentiation of these cells in vitro. These cells express pluripotency-associated markers enabling easy reprogramming. Based on the expression of renal associated genes, proteins and functionality, we refer to these cells as urine derived renal progenitor cells-UdRPCs. CHIR99021-induced differentiation of UdRPCs activated WNT-related genes-AXIN2, JUN and NKD1. Protein interaction network identified JUN as a putative regulator of differentiation whereas self-renewal is maintained by FGF2-driven TGF{beta}-SMAD2/3. Our data will enhance understanding of the molecular identities of UdRPCs, and enable the generation of renal disease models in vitro and eventually kidney-associated regenerative therapies.

developmental biology↗