Biology subjects

Piipponen, M.

Publications and source records attributed to Piipponen, M..

5 recordsLinked to original sources

bioRxiv2025

Adipose tissue-derived fibroblasts engage in immune-stromal crosstalk during obesity-aggravated atherosclerosis in mice

Atherosclerosis involves changes in the vascular wall and surrounding perivascular adipose tissue, yet the cellular contributors to disease progression remain incompletely understood. Obesity exacerbates atherogenesis, but the cell types driving this aggravation are unclear. We aimed to define the key cell populations across tissues in a highly atherogenic mouse model under obese and normal-weight conditions and to identify obesity-associated cellular changes. We employed 5 single-cell RNA sequencing combined with antibody staining in Ldlr-/-Apob100/100 male mice fed either a high-fat or control diet. Aorta, perivascular and epididymal adipose tissues, and spleen were analyzed, with CD45 enrichment of aortic samples and CITE-seq using a 138-antibody panel. Key findings were validated in mice by immunohistochemistry and multiplexed immunofluorescence and explored in human aorta and carotid arteries using spatial transcriptomics. Analysis of [~]46,000 cells enabled characterization of cell states, gene enrichment, regulon activity, and inferred interactions. Adipose-derived fibroblast subsets displayed immune-associated transcriptional programs in obesity. Pi16 progenitor fibroblasts were reduced alongside marked PVAT remodeling, and the top mouse differentially expressed genes exhibited clear spatial patterning in human arteries.

genomics↗

bioRxiv2024

Circular RNA circASH1L(4,5) protects microRNA-129-5p from target-directed microRNA degradation in human skin wound healing

Both circular RNAs (circRNA) and microRNAs (miRNA) have emerged to play important roles in health and disease. To understand their function in tissue repair, we profiled circRNA, linear RNA, and miRNA expression dynamics in human wound-edge keratinocytes across the wound healing process. Our investigation spotlighted circASH1L(4,5) and its engagement with miR-129-5p, both of which levels were increased with wound repair. Unlike conventional miRNA sponging, circASH1L enhanced miR-129 stability and silencing activity by protecting this miRNA from target-directed miRNA degradation (TDMD) triggered by NR6A1 mRNA. TGF-{beta} signaling, pivotal in wound healing, fostered circASH1L expression while suppressing NR6A1, thus enhancing the miR-129 abundance at the post-transcriptional level. Functionally, circASH1L and miR-129 enhanced keratinocyte migration and proliferation, crucial for re-epithelialization of human wounds. Collectively, our study uncovers circRNAs novel role as shields for miRNAs and sheds light on the physiological importance of regulated miRNA degradation in human skin wound healing.

molecular biology↗

bioRxiv2023

Clustering of RNA co-expression network identifies novel long non-coding RNA biomarkers in squamous cell carcinoma

Long non-coding RNAs (lncRNAs) have been shown to play an important role in cancer progression. Cutaneous squamous cell carcinoma is the most common metastatic skin cancer with increasing incidence worldwide. The prognosis of the metastatic cSCC is poor, and currently there are no established biomarkers to predict metastatic risk nor specific therapeutic targets for advanced or metastatic cSCC. To elucidate the role of lncRNAs in cSCC, RNA sequencing of patient derived cSCC cell lines and normal human epidermal keratinocytes was performed. The correlation analysis of differentially expressed lncRNA and protein-coding genes revealed six distinct clusters. One of the upregulated clusters involved genes related to cell motility. Upregulation of the expression of lncRNAs involved in cSCC cell motility in cSCC and head and neck SCC (HNSCC) cells was confirmed by qRT-PCR. Upregulation of HOTTIP and LINC00543 was also noted in SCC tumors in vivo and was associated with worse prognosis in HNSCC and lung SCC cohorts in the TCGA data, respectively. Altogether, these results reveal a novel set of lncRNAs involved in cSCC cell locomotion. These lncRNAs may serve as potential novel biomarkers or a biomarker panel and as putative therapeutic targets in locally advanced and metastatic cSCC.

cancer biology↗

bioRxiv2022

The injury-induced circular RNA circGLIS3 activates dermal fibroblasts to promote wound healing

Delayed skin wound healing and excessive scarring are consequences of an impaired healing process and represent a major health and economic burden worldwide. Current intervention strategies lack efficacy and suffer from high recurrence rates necessitating the investigation into alternative treatment modalities like circular RNAs (circRNAs). By RNA sequencing, we profiled circRNA expression changes during human skin wound healing as well as in keratinocytes and fibroblasts isolated from donor-matched skin and acute wounds. CircGLIS3 was found to be transiently upregulated in the dermal fibroblasts upon skin injury, which was at least partially due to the activated IL-1 signaling. Similarly, overabundant circGLIS3 expression was detected in human keloid lesions compared to the surrounding healthy skin. We found that circGLIS3 resided mainly in the cytoplasm, where it interacted with and stabilized Procollagen C-endopeptidase enhancer 1 (PCPE-1) protein to enhance TGF-{beta} signaling, fibroblast activation, and production of extracellular matrix - important biological processes required for wound repair. Accordingly, knockdown of circGLIS3 in human ex vivo wounds potently reduced wound contraction and delayed re-epithelialization. Collectively, we have identified a previously uncharacterized circRNA regulator of human skin wound healing that may open an avenue for circRNA-based therapeutics for abnormal scarring or nonhealing wounds. One Sentence SummaryTransient increase of the circular RNA circGLIS3 promotes the wound fibroblast activation and extracellular matrix production to facilitate wound closure.

molecular biology↗

bioRxiv2022

Human skin specific long noncoding RNA HOXC13-AS regulates epidermal differentiation by interfering with Golgi-ER retrograde transport

After a skin injury, keratinocytes switch from a state of homeostasis to one of regeneration leading to the reconstruction of the epidermal barrier. The regulatory mechanism of gene expression underpinning this key switch during human skin wound healing is enigmatic. Long noncoding RNAs (lncRNAs) constitute a new horizon in the understanding of the regulatory programmes encoded in the mammalian genome. By comparing the transcriptome of an acute human wound and skin from the same donor as well as keratinocytes isolated from these paired tissue samples, we generated a list of lncRNAs showing changed expression in keratinocytes during wound repair. Our study focused on HOXC13-AS, a recently evolved human lncRNA specifically expressed in epidermal keratinocytes, and we found that its expression was temporally downregulated during wound healing. In line with its enrichment in suprabasal keratinocytes, HOXC13-AS was found to be increasingly expressed during keratinocyte differentiation, but its expression was reduced by EGFR signalling. After HOXC13-AS knockdown or overexpression in human primary keratinocytes undergoing differentiation induced by cell suspension or calcium treatment and in organotypic epidermis, we found that keratinocyte differentiation was promoted, while the cell inflammatory response was suppressed. Moreover, RNA pull-down assays followed by mass spectrometry and RNA immunoprecipitation analysis revealed that mechanistically HOXC13-AS sequestered the coat complex subunit alpha (COPA) protein and interfered with Golgi-to-endoplasmic reticulum (ER) molecular transport, resulting in ER stress and enhanced keratinocyte differentiation. In summary, we identified HOXC13-AS as a crucial regulator of human epidermal differentiation.

molecular biology↗