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Träfflista för sökning "AMNE:(NATURAL SCIENCES Biological Sciences Biochemistry and Molecular Biology) ;pers:(Lammi Mikko 1961)"

Search: AMNE:(NATURAL SCIENCES Biological Sciences Biochemistry and Molecular Biology) > Lammi Mikko 1961

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1.
  • Zhang, Feng'e, et al. (author)
  • Cell cycle-related lncRNAs and mRNAs in osteoarthritis chondrocytes in a Northwest Chinese Han Population
  • 2020
  • In: Medicine. - : Lippincott Williams & Wilkins. - 0025-7974 .- 1536-5964. ; 99:24
  • Journal article (peer-reviewed)abstract
    • Background: A group of differentially expressed long non-coding RNAs (lncRNAs) have been shown to play key roles in osteoarthritis (OA), although they represented only a small proportion of lncRNAs that may be biologically and physiologically relevant. Since our knowledge of regulatory functions of non-coding RNAs is still limited, it is important to gain better understanding of their relation to the pathogenesis of OA.Methods: We performed mRNA and lncRNA microarray analysis to detect differentially expressed RNAs in chondrocytes from three OA patients compared with four healthy controls. Then, enrichment analysis of the differentially expressed mRNAs was carried out to define disease molecular networks, pathways and gene ontology (GO) function. Furthermore, target gene prediction based on the co-expression network was performed to reveal the potential relationships between lncRNAs and mRNAs, contributing an exploration of a role of lncRNAs in OA mechanism. Quantitative RT-PCR analyses were used to demonstrate the reliability of the experimental results.Findings: Altogether 990 lncRNAs (666 up-regulated and 324 down-regulated) and 546 mRNAs (419 up-regulated and 127 down-regulated) were differentially expressed in OA samples compared with the normal ones. The enrichment analysis revealed a set of genes involved in cell cycle. In total, 854 pairs of mRNA and lncRNA were highly linked, and further target prediction appointed 12 genes specifically for their corresponding lncRNAs. The lncRNAs lncRNA-CTD-2184D3.4, ENST00000564198.1, and ENST00000520562.1 were predicted to regulate SPC24, GALM, and ZNF345 mRNA expressions in OA.Interpretation: This study uncovered several novel genes potentially important in pathogenesis of OA, and forecast the potential function of lnc-CTD-2184D3.4, especially for the cell cycle in the chondrocytes. These findings may promote additional aspects in studies of OA.
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2.
  • Kaarniranta, Kai, et al. (author)
  • Primary chondrocytes resist hydrostatic pressure-induced stress while primary synovial cells and fibroblasts show modified Hsp70 response.
  • 2001
  • In: Osteoarthritis and Cartilage. - : Saunders Elsevier. - 1063-4584 .- 1522-9653. ; 9:1, s. 7-13
  • Journal article (peer-reviewed)abstract
    • OBJECTIVE: During joint loading, chondrocytes in the articular cartilage are subjected to gradients of high compressive hydrostatic pressure (HP). In response to diverse chemical or physical stresses, heat shock genes are induced to express heat shock proteins (Hsps). This study sought to examine the role of Hsps in baroresistance in primary bovine chondrocytes and synovial cells, as well as in primary human fibroblasts.METHODS: Northern blotting was used to analyze the steady-state levels of hsp70 mRNA in the primary cells exposed to HP or heat stress. Hsp70 protein accumulation was analyzed by Western blotting, and the DNA-binding activity was examined by gel mobility shift assay.RESULTS: Primary bovine chondrocytes which have been adapted to live under pressurized conditions showed negligible Hsp70 response upon HP loading, whereas primary bovine synovial cells and human fibroblasts accumulated hsp70 mRNA and protein when subjected to HP. The response was initiated without activation of the heat shock transcription factor 1. Interestingly, pre-conditioning of the barosensitive fibroblasts with HP or heat shock reduced the Hsp70 response, indicating induction of baroresistance.CONCLUSION: This study suggests that Hsp70 can play an important role in the early stages of adaptation of cells to HP. Thus, the Hsp70 gene expression upon HP loading may serve as one indicator of the chondrocytic phenotype of the cells. This can be of use in the treatment of cartilage lesions.
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3.
  • Zhao, Guang-Hui, et al. (author)
  • A preliminary analysis of microRNA profiles in the subchondral bone between Kashin-Beck disease and primary knee osteoarthritis
  • 2019
  • In: Clinical Rheumatology. - : Springer Science and Business Media LLC. - 0770-3198 .- 1434-9949. ; 38:9, s. 2637-2645
  • Journal article (peer-reviewed)abstract
    • INTRODUCTION: Kashin-Beck disease (KBD) is a chronic osteochondral disorder primarily associated with cartilage degeneration. The bone texture structure in KBD was also changed but it was not identical to primary knee osteoarthritis (OA). This study investigates the differences in microRNA (miRNA) profiles of subchondral bone collected from patients suffering from KBD in comparison with those with primary knee osteoarthritis (OA).METHODS: Subchondral bone tissues were taken from four patients with KBD and four patients with primary knee OA undergoing total knee replacement. The miRNA array profiling was performed using an Affymetrix miRNA 4.0 Array, and then the target gene predictions and function annotations of the predicted targets were performed.RESULTS: Our results showed that 124 miRNAs had lower expression levels in the subchondral bone sampled from KBD patients in comparison with OA patients. Gene ontology (GO) and KEGG pathway analyses of the predicted targets demonstrated numerous significantly enriched GO terms and signal pathways essential for bone development and integrity, such as metabolic processes, PI3K-Akt, and MAPK signaling pathways.CONCLUSIONS: Our study confirms that a large set of miRNAs are differentially expressed in the subchondral bone of patients with KBD and OA and contributes new insights into potential pathological changes in the subchondral bone of KBD patients.
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4.
  • Lammi, Mikko, 1961- (author)
  • Influences of in vivo and in vitro loading on the proteoglycan synthesis of articular cartilage chondrocytes
  • 1993
  • Doctoral thesis (other academic/artistic)abstract
    • In this study, the biosynthesis of proteoglycans (PGs) was examined in articular cartilage of canine hip joint after long-distance running experiment and in bovine chondrocyte cultures during in vitro loading with hydrostatic pressure. In addition, new assays were developed for more sensitive quantitation of glycosaminoglycans (GAGs) and PGs.Anterior (weight-bearing) and posterior (less weight-bearing) areas of the femoral head from young beagles were labeled after long-term, longdistance running exercise. Total sulpahte incorporation rates were determined and distribution of of the incorporated sulphate in the tissue was localized by quantitative autoradiography. Concentration and extractability of the PGs were determined, and PG structures were studied by gel filtration, agarose gel electrophoresis, and chemical determinations. In the less weight-bearing area, the amount of extractable PGs was decreased, simultaneously with an increased concentration of residual GAGs in the tissue after 4M GuCl extraction. In the weight-bearing area, no marked alterations were noticed. The congruency of the femoral head seems to protect the cartilage from untoward alterations that occur in the femoral head condyles subjected to the same running program.The effect of hydrostatic pressure on PG metabolism of chondrocyte cultures was examined during 20 hours' exposure of chondrocytes to 5 and 30 MPa pressures. The continuous 30 MPa pressure reduced total PG synthesis by 37 % as measured by [35S]sulphate incorporation, in contrast to the 5 MPa which had no effect. Continuous 30 MPa hydrostatic pressure also reduced the steady-state mRNA level of aggrecan. The cyclic pressures showed a frequency dependent stimulation (0.5 Hz, + 11 %) or inhibition (0.017 Hz, -17 %). Aggrecans secreted under continuous 30 MPa pressure showed a retarded migration in 0.75 % SDS-agarose gel electrophoresis and also eluted earlier on Sephacryl S-1000 gel filtration, indicative of larger molecular size. The results demonstrate that high hydostatic pressure can influence the synthesis of PGs in chondrocytes both at the transcriptionl and translational/posttranslational levels.
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5.
  • Pienimaki, Juha-Pekka, et al. (author)
  • Epidermal growth factor activates hyaluronan synthase 2 in epidermal keratinocytes and increases pericellular and intracellular hyaluronan.
  • 2001
  • In: Journal of Biological Chemistry. - : American Society of Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 276:23, s. 20428-20435
  • Journal article (peer-reviewed)abstract
    • Hyaluronan is an abundant and rapidly turned over matrix molecule between the vital cell layers of the epidermis. In this study, epidermal growth factor (EGF) induced a coat of hyaluronan and a 3-5-fold increase in its rate of synthesis in a rat epidermal keratinocyte cell line that has retained its ability for differentiation. EGF also increased hyaluronan in perinuclear vesicles, suggesting concurrent enhancement in its endocytosis. Cell-associated hyaluronan was most abundant in elongated cells that were stimulated to migrate by EGF, as determined in vitro in a wound healing assay. Large fluctuations in the pool size of UDP-N-acetylglucosamine, the metabolic precursor of hyaluronan, correlated with medium glucose concentrations but not with EGF. Reverse transcriptase-polymerase chain reaction (RT-PCR) showed no increase in hyaluronan synthases 1 and 3 (Has1 and Has3), whereas Has2 mRNA increased 2-3-fold in less than 2 h following the introduction of EGF, as estimated by quantitative RT-PCR with a truncated Has2 mRNA internal standard. The average level of Has2 mRNA increased from approximately 6 copies/cell in cultures before change of fresh medium, up to approximately 54 copies/cell after 6 h in EGF-containing medium. A control medium with 10% serum caused a maximum level of approximately 21 copies/cell at 6 h. The change in the Has2 mRNA levels and the stimulation of hyaluronan synthesis followed a similar temporal pattern, reaching a maximum level at 6 h and declining toward 24 h, a finding in line with a predominantly Has2-dependent hyaluronan synthesis and its transcriptional regulation.
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6.
  • Rilla, Kirsi, et al. (author)
  • Changed lamellipodial extension, adhesion plaques and migration in epidermal keratinocytes containing constitutively expressed sense and antisense hyaluronan synthase 2 (Has2) genes.
  • 2002
  • In: Journal of Cell Science. - Cambridge : The Company of Biologists. - 0021-9533 .- 1477-9137. ; 115, s. 3633-3643
  • Journal article (peer-reviewed)abstract
    • Hyaluronan is a major component of the epidermal extracellular matrix, is actively synthesized by keratinocytes and shows fast matrix turnover in the stratified epithelium. We probed the importance of hyaluronan synthesis in keratinocytes by establishing cell lines carrying the exogenous hyaluronan synthase 2 (Has2) gene in sense and antisense orientations to increase and decrease their hyaluronan synthesis, respectively. Compared with cell lines transfected with the vector only, most clones containing the Has2 sense gene migrated faster in an in vitro wounding assay, whereas Has2 antisense cells migrated more slowly. Has2 antisense clones showed delayed entry into the S phase of cell cycle following plating, smaller lamellipodia and less spreading on the substratum. The decrease of hyaluronan on the undersurface of Has2 antisense cells was associated with an increased area of adhesion plaques containing vinculin. Exogenous hyaluronan added to the keratinocyte cultures had a minor stimulatory effect on migration after wounding but did not restore the reduced migratory ability of Has2 antisense cells. Hyaluronan decasaccharides that displace receptor bound hyaluronan in keratinocytes, and Streptomyces hyaluronidase sufficient to remove most cell surface hyaluronan had little effect on cell migration. The results suggest that the dynamic synthesis of hyaluronan directed by Has2, rather than the abundance of pericellular hyaluronan, controls keratinocyte migration, a cell function vital for the repair of squamous epithelia following wounding.
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7.
  • Fan, Yue, et al. (author)
  • Unveiling inflammatory and prehypertrophic cell populations as key contributors to knee cartilage degeneration in osteoarthritis using multi-omics data integration
  • 2024
  • In: Annals of the Rheumatic Diseases. - : BMJ Publishing Group Ltd. - 0003-4967 .- 1468-2060.
  • Journal article (peer-reviewed)abstract
    • OBJECTIVES: Single-cell and spatial transcriptomics analysis of human knee articular cartilage tissue to present a comprehensive transcriptome landscape and osteoarthritis (OA)-critical cell populations.METHODS: Single-cell RNA sequencing and spatially resolved transcriptomic technology have been applied to characterise the cellular heterogeneity of human knee articular cartilage which were collected from 8 OA donors, and 3 non-OA control donors, and a total of 19 samples. The novel chondrocyte population and marker genes of interest were validated by immunohistochemistry staining, quantitative real-time PCR, etc. The OA-critical cell populations were validated through integrative analyses of publicly available bulk RNA sequencing data and large-scale genome-wide association studies.RESULTS: We identified 33 cell population-specific marker genes that define 11 chondrocyte populations, including 9 known populations and 2 new populations, that is, pre-inflammatory chondrocyte population (preInfC) and inflammatory chondrocyte population (InfC). The novel findings that make this an important addition to the literature include: (1) the novel InfC activates the mediator MIF-CD74; (2) the prehypertrophic chondrocyte (preHTC) and hypertrophic chondrocyte (HTC) are potentially OA-critical cell populations; (3) most OA-associated differentially expressed genes reside in the articular surface and superficial zone; (4) the prefibrocartilage chondrocyte (preFC) population is a major contributor to the stratification of patients with OA, resulting in both an inflammatory-related subtype and a non-inflammatory-related subtype.CONCLUSIONS: Our results highlight InfC, preHTC, preFC and HTC as potential cell populations to target for therapy. Also, we conclude that profiling of those cell populations in patients might be used to stratify patient populations for defining cohorts for clinical trials and precision medicine.
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8.
  • Chang, Yanhai, et al. (author)
  • Inflammatory cytokine of IL-1β is involved in T-2 toxin-triggered chondrocyte injury and metabolism imbalance by the activation of Wnt/β-catenin signaling
  • 2017
  • In: Molecular Immunology. - : Elsevier. - 0161-5890 .- 1872-9142. ; 91, s. 195-201
  • Journal article (peer-reviewed)abstract
    • Mycotoxin T-2 exerts a causative role in Kashin-Beck disease (KBD) suffering chondrocyte apoptosis and cartilage matrix homeostasis disruption. Recent research corroborated the aberrant levels of pro-inflammatory cytokine IL-1ß in KBD patients and mycotoxin environment. In the present study, we investigated the relevance of IL-1ß in T-2 toxin-evoked chondrocyte cytotoxic injury and aberrant catabolism. High levels of IL-1ß were detected in serum and cartilages from KBD patients and in T-2-stimulated chondrocytes. Moreover, knockdown of IL-1ß antagonized the adverse effects of T-2 on cytotoxic injury by enhancing cell viability and inhibiting apoptosis. However, exogenous supplementation of IL-1β further aggravated cell damage in response to T-2. Additionally, cessation of IL-1β rescued T-2-elicited tilt of matrix homeostasis toward catabolism by elevating the transcription of collagen II and aggrecan, promoting release of sulphated glycosaminoglycans (sGAG) and TIMP1, and suppressing matrix metalloproteinases production including MMP-1, MMP-3 and MMP-13. Conversely, IL-1β stimulation deteriorated T-2-induced disruption of matrix metabolism balance toward catabolism. Mechanistic analysis found the high activation of Wnt/β-catenin in KBD patients and chondrocytes upon T-2. Furthermore, this activation was mitigated after IL-1β inhibition, but further enhanced following IL-1β precondition. Importantly, blocking this pathway by transfection with β-catenin alleviated the adverse roles of IL-1β on cytotoxic injury and metabolism disorders under T-2 conditioning. Together, this study elucidates a new insight into how T-2 deteriorates the pathological progression of KBD by regulating inflammation-related pathways, indicating a promising anti-inflammation strategy for KBD therapy.
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9.
  • Lammi, Mikko J., 1961-, et al. (author)
  • Regulation of oxygen tension as a strategy to control chondrocytic phenotype for cartilage tissue engineering and regeneration
  • 2024
  • In: Bioengineering. - : MDPI. - 2306-5354. ; 11:3
  • Journal article (peer-reviewed)abstract
    • Cartilage defects and osteoarthritis are health problems which are major burdens on health care systems globally, especially in aging populations. Cartilage is a vulnerable tissue, which generally faces a progressive degenerative process when injured. This makes it the 11th most common cause of global disability. Conservative methods are used to treat the initial phases of the illness, while orthopedic management is the method used for more progressed phases. These include, for instance, arthroscopic shaving, microfracturing and mosaicplasty, and joint replacement as the final treatment. Cell-based implantation methods have also been developed. Despite reports of successful treatments, they often suffer from the non-optimal nature of chondrocyte phenotype in the repair tissue. Thus, improved strategies to control the phenotype of the regenerating cells are needed. Avascular tissue cartilage relies on diffusion for nutrients acquisition and the removal of metabolic waste products. A low oxygen content is also present in cartilage, and the chondrocytes are, in fact, well adapted to it. Therefore, this raises an idea that the regulation of oxygen tension could be a strategy to control the chondrocyte phenotype expression, important in cartilage tissue for regenerative purposes. This narrative review discusses the aspects related to oxygen tension in the metabolism and regulation of articular and growth plate chondrocytes and progenitor cell phenotypes, and the role of some microenvironmental factors as regulators of chondrocytes.
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  • Result 1-10 of 96

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