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The main objective of our research is to investigate the molecular mechanisms of cell migration, proliferation, and differentiation, and the implication of miRNAs in these processes.
- Migrating cells such as human mesenchymal stem cells (hMSCs), monocytes, and keratinocytes play key roles in multiple normal processes and inflammatory diseases including atherosclerosis, cancer, and wound healing. Our research aims to gain deeper insights into molecular mechanisms that regulate the behavior and function of these cells. This may provide innovative approaches for target-directed therapeutical intervention.
- microRNAs (miRNAs) represent a group of small non-coding RNA molecules which are expressed in all cell types at different quantities. By sequence complementarity, miRNAs specifically bind to target mRNAs and thereby reduce or abolish protein expression. miRNAs are involved in the normal functioning of cells, so has dysregulation of miRNA been associated with disease.
- Migrating cells such as human mesenchymal stem cells (hMSCs), monocytes, and keratinocytes play key roles in multiple normal processes and inflammatory diseases including atherosclerosis, cancer, and wound healing. Our research aims to gain deeper insights into molecular mechanisms that regulate the behavior and function of these cells. This may provide innovative approaches for target-directed therapeutical intervention.
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miRNA Let-7f
Human mesenchymal stem cells (hMSCs) are recruited to tissue sites of damage and disease where they contribute to immunomodulation and repair. This multi-step process involves chemokine-directed migration of hMSCs and on-site release of factors that influence target cells and tissues.
- miRNA let-7f in atherosclerosis.
Fig.1: Elevated expression of let-7f facilitates LL-37-mediated recruitment of hMSCs to atherosclerotic plaques involving upregulation of FPR2. Upon arrival in plaques, hMSCs release various bioactive molecules and differentiate into myogenic cells with a potentially athero-protective signature. Picture taken from Egea V. et al., Cardiovascular Research
- miRNA let-7f in tumor growth.
Attracted by the inflammatory milieu, hMSCs are known to infiltrate neoplastic tissues and affect tumor growth and progression. Our findings indicate that hMSC tropism toward tumor tissue is driven by paracrine SDF-1α and inflammatory cytokines as well as hypoxia. These conditions cause augmentation of endogenous let-7f in hMSCs promoting their invasion by increased secretion of ECM degrading proteases and elevated autophagy in these cells. Furthermore, we showed that elevated levels of let-7f in hMSCs facilitate its release in exosomes and uptake by mammary tumor cells thereby suppressing tumor growth. Our results support the idea of hMSCs or hMSC-derived exosomes in cell-based and cell-free clinical applications of anti-tumor therapy (Fig. 2).
Fig. 2: hMSC exposure to inflammatory cytokines, SDF-1α, and hypoxia upregulates let-7f in the cells promoting chemotactic invasion via engagement of autophagy and release of ECM-degrading proteases. In a paracrine manner, exosomal let-7f affects tumor growth (Egea V. et al., Cell Death and Disease, 2021).
- Summary and conclusions
let-7f is a key promotor of hMSC tropism to neoplasias and atheromas enhancing the anti-tumor and athero-protective potential of these cells. In the future, increasing let-7f levels in hMSCs may represent a strategy to advance the clinical application of these cells in the treatment of inflammatory diseases.
Sulfur mustard
Sulfur mustard (SM) is a cytotoxic chemical warfare agent. Exposure of the skin to SM evokes severe inflammation, extensive blistering and impaired wound healing. The precise pathomechanisms in the affected skin, however, are still unclear. To date, there are no effective treatments available. We hypothesize that SM might disturb the homeostatic balance of miRNA expression in skin cells causing dysregulation of cellular processes such as proliferation, migration and differentiation which are essential in wound healing.
- miR-203 and miR-210 are regulators of keratinocyte function
We demonstrated that SM upregulates miR-203 in primary human keratinocytes under normoxia and hypoxia, and augments hypoxia-induced levels of miR-210 in these cells thereby affecting cellular viability, proliferation, and differentiation. These deficiencies were efficiently counteracted by the application of specific inhibitors of miR-203 and miR-210 (anti-miRs), providing evidence that miRNAs are key regulators in normal and SM-affected keratinocyte functionality (Deppe J. et al., Toxicology Letters, 2016).
- mRNA and miRNA transcriptome analysis of SM-exposed keratinocytes
In our recent project funded by DFG and Bundeswehr, we discovered a SM-triggered pathomechanism involving miR-497-5p and its target survivin which contributes to keratinocyte dysfunction. Transcriptome analysis using RNA-seq in NHEK revealed that SM evoked differential expression of 1896 mRNAs and 25 miRNAs with many of these RNAs known to be involved in keratinocyte function and wound healing. We demonstrated that keratinocyte differentiation and proliferation were efficiently regulated by miRNAs induced in skin cells after exposure to SM. The inhibition of miR-497-5p counteracted SM-induced premature differentiation and stimulated proliferation of NHEK. In addition, we showed that microneedle-mediated transdermal application of lipid-nanoparticles containing miR-497-5p inhibitor restored survivin biosynthesis and cellular functionality upon exposure to SM using human skin biopsies. Our findings expand the current understanding of SM-associated molecular toxicology in keratinocytes and highlight miR-497-5p as feasible clinical target for specific skin therapy in SM-exposed patients and beyond (Fig. 3).
Fig. 3: Exposure of the skin with the chemical warfare agent sulfur mustard (SM) causes dysfunctional wound healing. The application of a specific miRNA inhibitor rescued SM-induced functional defects in keratinocytes in vitro and ex vivo (Egea V. et al., Cell Death & Disease, 2024)
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GROUP MEMBERS
Christian Ries, PhDPrincipal Investigator
Virginia Egea, PhDPostdoctoral researcherÖlDpxlul,gsNxigvimd/ävfsmi
Karina Lutterberg, DVMPostdoctoral researcherÜdgplugeVfbdbipjipxvim-ävfemi
Thomas PitschTechnicianAlumniTanja Popp, former PostDoc
Janina Deppe, former PhD student
Christian Mahl, former PhD student
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Egea V, Lutterberg K, Steinritz D, Rothmiller S, Steinestel K, Caca J, Nerlich A, Blum H, Reschke S, Khani S, Bartelt A, Worek F, Thiermann H, Weber C, Ries C. Targeting miR-497-5p rescues human keratinocyte dysfunction upon skin exposure to sulfur mustard. Cell Death & Disease, 10;15(8):585, 2024Egea V, Megens RTA, Santovito D, Wantha S, Brandl R, Siess W, Khani S, Soehnlein O, Bartelt A, Weber C, Ries C. Properties and fate of human mesenchymal stem cells upon miRNA let-7f-promoted recruitment to atherosclerotic plaques. Cardiovascular Research, 119(1):155-166, 2023
Egea V, Kessenbrock K, Lawson D, Bartelt A, Weber C, Ries C. Let-7f miRNA regulates SDF-1α- and hypoxia-promoted migration of mesenchymal stem cells and attenuates mammary tumor growth upon exosomal release. Cell Death & Disease, 12:516, 2021.Mahl C, Egea V, Megens RT, Pitsch T, Santovito D, Weber C, Ries C. RECK (reversion-inducing cysteine-rich protein with Kazal motifs) regulates migration, differentiation and Wnt/β-catenin signaling in human mesenchymal stem cells. Cellular and Molecular Life Sciences, 273(7): 1489-1501, 2016
Deppe J, Steinritz D, Santovito D., Egea V, Schmidt A, Weber C, Ries C. Upregulation of miR-203 and miR-210 affect growth and differentiation of keratinocytes after exposure to sulfur mustard in normoxia and hypoxia. Toxicology Letters, 244:81-87, 2016
Popp T, Steinritz D, Breit A, Deppe J, Egea V, Schmidt A, Gudermann T, Weber C, Ries C. Wnt5a/β-catenin signaling drives calcium-induced differentiation of human primary keratinocytes. Journal of Investigative Dermatology, 134:2183-2191, 2014
Ries C. Cytokine functions of TIMP-1. Cellular and Molecular Life Sciences, 71(4):659-672, 2014
Egea V, Zahler S, Rieth N, Neth P, Popp T, Kehe K, Jochum M, Ries C. Tissue inhibitor of metalloproteinase-1 (TIMP-1) regulates mesenchymal stem cells through let-7f microRNA and Wnt/beta-catenin signaling. PNAS USA, 109(6):E309-16, 2012
Egea V, Schichor C, Popp T, Neth P, Karow M, Goldbrunner R, Berninger B, Jochum M, Ries C. TNF-α regulation of ERK1/2 respecifies human mesenchymal stem cells to a neural fate and promotes CXCR4/SDF-1 mediated migration. Cell Death and Differentiation, 18:853-863, 2011
Ries C, Egea V, Karow M, Kolb H, Jochum M, and Neth P. MMP-2, MT1-MMP, and TIMP-2 are essential for the invasive capacity of human mesenchymal stem cells: differential regulation by inflammatory cytokines. Blood, 109:4055-4063, 2007
Ries C, Pitsch T, Mentele R, Zahler S, Egea V, Nagase H, and Jochum M. Identification of a novel 82-kDa variant of proMMP-9 associated with the surface of leukemic cells: (auto-)catalytic activation and resistance to inhibition by TIMP-1. Biochemical Journal, 405:547-558, 2007
Ries C, Kolb H, and Petrides PE. Regulation of 92-kDa gelatinase release in HL-60 leukaemia cells: Tumor necrosis factor-α as an autocrine stimulus for basal- and phorbol ester-induced secretion. Blood, 83:3638-3646, 1994
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Christian Ries, PhDPrincipal Investigator+49-(0)89-4400-55310
Virginia Egea, PhDPostdoctoral researcher
Karina Lutterberg, DVMPostdoctoral researcher
Thomas PitschTechnician+49-(0)89-4400-43911
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