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- Luo, Longlong
(författare)
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Deciphering the complexity of psoriasis : non-coding RNAs and cellular interactions
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Psoriasis is a prevalent immune-mediated skin disorder marked by chronically relapsing inflammation and epidermal hyperproliferation. As researchers delve deeper into the molecular intricacies of psoriasis, emerging evidence hints at the roles of non-coding RNAs (ncRNAs). Among these, long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are of particular interest. While lncRNAs have regulatory capabilities that are yet to be fully mapped in psoriasis, miRNAs are established as crucial regulators of gene expression, especially in immune responses and inflammation. They are believed to modulate cellular function and inflammatory circuits in psoriasis as well as bridge the communication between infiltrating immune cells and keratinocytes. Although the chronic skin inflammation in psoriasis arises from an intricate interplay between immune cells and keratinocytes, the specific cell subsets involved and the extent of their cellular interactions in the psoriatic epidermis remain to be fully delineated. Together, the potential roles of ncRNAs (paper I-III) and the delicate cell-to-cell interactions (Paper IV) in the psoriatic epidermis emerge as central themes in psoriasis studies. Paper I: In this study, we spotlight LINC00958, a lncRNA notably elevated in psoriasis keratinocytes, as revealed through our transcriptomic analysis comparing psoriatic and healthy skin samples. Validations using RT-qPCR and in situ hybridization affirmed its heightened expression. Subcellular localization studies found LINC00958 predominantly in the keratinocyte cytoplasm. Interestingly, the psoriasis-associated cytokine, IL-17A, upregulates LINC00958 through the C/EBP-β and p38 pathways. When LINC00958 was inhibited, there was a marked decline in keratinocyte proliferation, corroborated by multiple assays including EdU incorporation and IncuCyte. Our transcriptomic insights from LINC00958-depleted keratinocytes underscored a set of dysregulated genes enriched to proliferation and cell cycle. Notably, LINC00958 inhibition moderated both inherent and IL-17A-stimulated p38 phosphorylation, effectively tempering IL-17A-driven keratinocyte growth. Collectively, our findings position LINC00958 as a critical lncRNA accentuating the IL-17A-fueled hyperproliferation in psoriasis. Paper II: In this study, we unveil a miRNA-mediated mechanism in psoriasis, wherein sensitizes keratinocytes to inflammatory triggers. IFN-γ treatment leads to rapid and sustained reduction in miR-149 levels in keratinocytes. This reduction in miR-149 results in extensive transcriptomic alterations and the upregulation of inflammatory markers, including IL-6, accompanied by an enhancement of the TWEAK pathway. We've also found that miR-149 directly targets the TWEAK receptor (TWEAKR), a novel discovery with clinical relevance highlighted by reduced miR-149 expression in psoriasis keratinocytes and the positive effects of synthetic miR-149 in a psoriasis mouse model induced by imiquimod (IMQ). These findings elucidate a novel mechanism by which IFN-γ sensitizes keratinocytes for TWEAK/TWEAKR-triggered inflammation by downregulating miR-149. Paper III: To further elucidate the role of miR-149 in keratinocyte immune responses and skin homeostasis, we generated knockout mice with epidermisspecific deletion of miR-149 (Mir149EKO). Despite the genetic alteration, Mir149EKO mice presented normal skin phenotype unless provoked by inflammation. Intriguingly, Mir149EKO-derived keratinocytes displayed increased Tweakr expression and a stronger response to Tweak stimulation. Using IMQ to simulate psoriasis conditions, Mir149EKO mice manifested pronounced inflammation, observed through skin thickening, increased immune cells infiltration, and heightened psoriasis-associated inflammatory mediators. Genetic profiling further highlighted the escalated inflammation-associated genes in Mir149EKO skin after IMQ treatment. A similar exacerbated inflammatory response was observed upon IL-23 injection. Notably, neutralizing the effect of Tweak mitigated this amplified inflammation upon miR-149 deletion. Conclusively, miR-149 seems pivotal in moderating skin inflammation, with its absence potentially exacerbating Tweak/Tweakr-driven inflammatory conditions in psoriasis. Paper IV: In this study, we aimed to map cellular interactions in healthy and psoriatic epidermis. Using skin biopsies from healthy individuals and untreated psoriasis patients, we performed a partial dissociation of epidermal cells to preserve inherent cell-cell interactions. Subsequently, we categorized cells based on the presence of CD45 and analyzed them using single-cell RNA sequencing. Our results uncovered three distinct keratinocyte states with specific activation patterns and a dominant IFN-α signature. We also identified seven immune cell populations, including tissue-resident memory cells, increased to the psoriatic epidermis. Notably, we pinpointed and verified an exclusive population of pDCs in the psoriatic epidermis, emphasizing their potential role in the disease. Additionally, our analyses highlighted an amplified interaction between skin cells and immune components in psoriasis. Overall, our study offers profound insights into the psoriatic epidermal landscape, emphasizing the critical roles of activated pDCs and intensified cell interactions in the disease's progression.
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| 2. |
- Luo, Longlong, et al.
(författare)
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The Long Noncoding RNA LINC00958 Is Induced in Psoriasis Epidermis and Modulates Epidermal Proliferation
- 2023
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Ingår i: Journal of Investigative Dermatology. - : Elsevier. - 0022-202X .- 1523-1747. ; 143:6, s. 999-1010
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Tidskriftsartikel (refereegranskat)abstract
- Psoriasis is a common, immune-mediated skin disease characterized by epidermal hyperproliferation and chronic skin inflammation. Long noncoding RNAs are >200 nucleotide-long transcripts that possess important regulatory functions. To date, little is known about the contribution of long noncoding RNAs to psoriasis. In this study, we identify LINC00958 as a long noncoding RNA overexpressed in keratinocytes (KCs) from psoriasis skin lesions, in a transcriptomic screen performed on KCs sorted from psoriasis and healthy skin. Increased levels of LINC00958 in psoriasis KCs were confirmed by RT-qPCR and single-molecule in situ hybridization. Confocal microscopy and analysis of subcellular fractions showed that LINC00958 is mainly localized in the cytoplasm of KCs. IL-17A, a key psoriasis cytokine, induced LINC00958 in KCs through C/EBP-β and the p38 pathway. The inhibition of LINC00958 led to decreased proliferation as measured by Ki-67 expression, live cell analysis imaging, and 5-ethynyl-2-deoxyuridine assays. Transcriptomic analysis of LINC00958-depleted KCs revealed enrichment of proliferation- and cell cycle‒related genes among differentially expressed transcripts. Moreover, LINC00958 depletion led to decreased basal and IL-17A‒induced phosphorylation of p38. Furthermore, IL-17A‒induced KC proliferation was counteracted by the inhibition of LINC00958. In summary, our data support a role for the IL-17A‒induced long noncoding RNA, LINC00958, in the pathological circuits of psoriasis by reinforcing IL-17A‒induced epidermal hyperproliferation.
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| 3. |
- Srivastava, Ankit, et al.
(författare)
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Cross-talk between IFN-γ and TWEAK through miR-149 amplifies skin inflammation in psoriasis
- 2021
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier. - 0091-6749 .- 1097-6825. ; 147:6, s. 2225-2235
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Psoriasis is a chronic inflammatory skin disease with disturbed interplay between immune cells and keratinocytes. A strong IFN-γ signature is characteristic for psoriasis skin, but the role of IFN-γ has been elusive. MicroRNAs are short RNAs regulating gene expression.OBJECTIVE: Our aim was to investigate the role of miR-149 in psoriasis and in the inflammatory responses of keratinocytes.METHODS: miR-149 expression was measured by quantitative RT-PCR in keratinocytes isolated from healthy skin and lesional and nonlesional psoriasis skin. Synthetic miR-149 was injected intradermally into the back skin of mice, and imiquimod was applied to induce psoriasis-like skin inflammation, which was then evaluated at the morphologic, histologic, and molecular levels. miR-149 was transiently overexpressed or inhibited in keratinocytes in combination with IFN-γ- and/or TNF-related weak inducer of apoptosis (TWEAK)-treatment.RESULTS: Here we report a microRNA-mediated mechanism by which IFN-γ primes keratinocytes to inflammatory stimuli. Treatment with IFN-γ results in a rapid and long-lasting suppression of miR-149 in keratinocytes. Depletion of miR-149 in keratinocytes leads to widespread transcriptomic changes and induction of inflammatory mediators with enrichment of the TWEAK pathway. We show that IFN-γ-mediated suppression of miR-149 leads to amplified inflammatory responses to TWEAK. TWEAK receptor (TWEAKR/Fn14) is identified as a novel direct target of miR-149. The in vivo relevance of this pathway is supported by decreased miR-149 expression in psoriasis keratinocytes, as well as by the protective effect of synthetic miR-149 in the imiquimod-induced mouse model of psoriasis.CONCLUSION: Our data define a new mechanism, in which IFN-γ primes keratinocytes for TWEAK-induced inflammatory responses through suppression of miR-149, promoting skin inflammation.
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| 4. |
- Xia, Ping, et al.
(författare)
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miR ‐378a regulates keratinocyte responsiveness to interleukin‐17A in psoriasis
- 2022
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Ingår i: British Journal of Dermatology. - : John Wiley & Sons. - 0007-0963 .- 1365-2133. ; 187:2, s. 211-222
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Tidskriftsartikel (refereegranskat)abstract
- Background Psoriasis is an immune-mediated inflammatory skin disease, in which an interplay between infiltrating immune cells and keratinocytes sustains chronic skin inflammation. Interleukin (IL)-17A is a key inflammatory cytokine in psoriasis and its main cellular targets are keratinocytes.Objectives To explore the role of miR-378a in psoriasis.Methods Keratinocytes obtained from psoriatic skin and healthy epidermis were separated by magnetic sorting, and the expression of miR-378a was analysed by quantitative polymerase chain reaction. The regulation and function of miR-378a was studied using primary human keratinocytes. The expression of miR-378a was modulated by synthetic mimics, and nuclear factor kappa B (NF-κB) activity and transcriptomic changes were studied. Synthetic miR-378a was delivered to mouse skin in conjunction with induction of psoriasiform skin inflammation by imiquimod.Results We show that miR-378a is induced by IL-17A in keratinocytes through NF-κB, C/EBP-β and IκBζ and that it is overexpressed in psoriatic epidermis. In cultured keratinocytes, ectopic expression of miR-378a resulted in the nuclear translocation of p65 and enhanced NF-κB-driven promoter activity even in the absence of inflammatory stimuli. Moreover, miR-378a potentiated the effect of IL-17A on NF-κB nuclear translocation and downstream activation of the NF-κB pathway. Finally, injection of miR-378a into mouse skin augmented psoriasis-like skin inflammation with increased epidermal proliferation and induction of inflammatory mediators. Mechanistically, miR-378a acts as a suppressor of NFKBIA/IκBζ, an important negative regulator of the NF-κB pathway in keratinocytes.Conclusions Collectively, our findings identify miR-378a as an amplifier of IL-17A-induced NF-κB signalling in keratinocytes and suggest that increased miR-378a levels contribute to the amplification of IL-17A-driven skin inflammation in psoriasis.
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