{
  "abstract": "Background Fructosamine-3-Kinase (FN3K) is a crucial enzyme for protein deglycation, mitigating the accumulation of advanced glycation end-products (AGEs) that drive oxidative stress and chronic inflammation. FN3K phosphorylates fructosamines on lysine residues, facilitating AGE removal and preserving protein and mitochondrial function (Delpierre et al., 2000). Reduced FN3K activity leads to mitochondrial dysfunction, a hallmark of cardiovascular disease (CVD) and comorbidities such as diabetes and pulmonary fibrosis (Maillard et al., 2019; Semba et al., 2010). Currently FN3K and FN3K-RP expression is believed to be constitutively expressed and considered to be a ‘house-keeping’ gene who’s expression is vital for normal cellular function.Aim To Investigate FN3K expression in vascular cells (AoSMC, HUVEC, AoEC) and its functional impact on mitochondria and pro-fibrotic events.Methods Aortic smooth muscle and endothelial cells were treated with pro-inflammatory cytokines IL-1 and IL-6 along with a negative control. Expression of FN3K and FN3K-RP was assessed by qPCR, western blot and FN3K activity assays. Time-course experiments were also performed following IL-10 and TNF-α stimulation to assess dynamic regulation of FN3K expression. As a positive control and to assess the functional impact of reduced FN3K expression, cells were also subjected to FN3K knockdown. To further characterize FN3K-dependent transcriptional changes, bulk RNA sequencing was performed on control and FN3K-knockdown AoSMCs, followed by differential gene expression analysis.Results IL-1β treatment resulted in a transient increase in FN3K expression after 30 min (approximately 1.5–1.6-fold over baseline) in AoSMCs, followed by a significant suppression to ~0.2–0.3-fold (~70–80% reduction) by 24 h. In AoECs, FN3K expression decreased more rapidly, reaching ~0.4-fold (~60% reduction) by 2 h and maintaining suppression through 24 h. HUVECs showed a transient peak at 30 min (~4–5-fold) but returned to near-baseline by 2 h and were ~80% reduced by 24 h. FN3K-RP expression remained largely unchanged across all time points and cell types . IL-6 treatment had no significant effect on FN3K or FN3K-RP expression in AoSMCs, HUVECs with values fluctuating around baseline. Knockdown using siRNA achieved up to 90% suppression of FN3K mRNA levels in AoSMCs, confirming efficient silencing for functional studies. RNA-seq analysis identified FN3K-associated transcriptional reprogramming in AoSMCs, with differentially expressed genes enriched in pathways related to mitochondrial function, inflammation, and fibrosis.Conclusion Contradictory to current dogma, expression of FN3K is cytokine-responsive in aortic smooth muscle and endothelial cells, resulting in decreased expression upon treatment with IL-1β and partially with IL-6. Furthermore, it has been shown previously by our group that metformin can increase FN3K expression. It is anticipated that continuous localized pro-inflammatory episodes could lead to decreased mitochondrial function and promotion of fibrosis leading to conditions such aortic stenosis. Ongoing investigations are exploring this hypothesis.",
  "authors": [
    {
      "affiliations": [
        "University of Wolverhampton, Wolverhampton, United Kingdom"
      ],
      "name": "Nazia Aga"
    },
    {
      "affiliations": [
        "University of Wolverhampton, Wolverhampton, United Kingdom"
      ],
      "name": "Kinza Khan"
    },
    {
      "affiliations": [
        "University of Wolverhampton, Wolverhampton, United Kingdom"
      ],
      "name": "Paul Kirkham"
    }
  ],
  "title": "549 Regulation of Fructosamine-3-Kinase (FN3K) in aortic smooth muscle and endothelial cells: Implications for cardiovascular disease",
  "uid": "ab843423-6e80-5343-adc7-29c2aaebe25c"
}