BMAL1, the nonredundant transcription factor in the core molecular clock, has been implicated in cardiometabolic diseases in mice and humans. BMAL1 controls the cyclic trafficking of Ly6c monocytes to sites of acute inflammation. Myeloid deficiency of also worsens chronic inflammation in diet-induced obesity. We studied whether myeloid deletion promotes atherosclerosis by enhancing monocyte recruitment to atherosclerotic lesions. By generating ;LysM mice on the Apoe background, we showed that deletion in myeloid cells increased the size of atherosclerotic lesions. deficiency in monocytes and macrophages resulted in an increased total number of lesional macrophages in general and Ly6c infiltrating monocyte-macrophages in particular, accompanied by skewed M2 to M1 macrophage phenotype. Ly6c and/or Ly6c monocyte subsets in blood, spleen, and bone marrow were not altered. Cell tracking and adoptive transfer of Ly6c monocytes showed deficiency induced more trafficking of Ly6c monocytes to atherosclerotic lesions, preferential differentiation of Ly6c monocytes into M1 macrophages, and increased macrophage content and lesion size in the carotid arteries. We demonstrated that deficiency in macrophages promotes atherosclerosis by enhancing recruitment of Ly6c monocytes to atherosclerotic lesions.-Huo, M., Huang, Y., Qu, D., Zhang, H., Wong, W. T., Chawla, A., Huang, Y., Tian, X. Y. Myeloid deletion increases monocyte recruitment and worsens atherosclerosis.
Objective—
TFEB (transcription factor EB) was recently reported to be induced by atheroprotective laminar flow and play an anti-atherosclerotic role by inhibiting inflammation in endothelial cells (ECs). This study aims to investigate whether TFEB regulates endothelial inflammation in diabetic
db/db
mice and the molecular mechanisms involved.
Approach and Results—
Endothelial denudation shows that TFEB is mainly expressed in ECs in mouse aortas. Western blotting shows TFEB total protein level decreases whereas the p-TFEB S142 (phosphorylated form of TFEB) increases in
db/db
mouse aortas, suggesting a decreased TFEB activity. Adenoviral TFEB overexpression reduces endothelial inflammation as evidenced by decreased expression of vascular inflammatory markers in
db/db
mouse aortas, and reduced expression of a wide range of adhesion molecules and chemokines in human umbilical vein ECs. Monocyte attachment assay shows TFEB suppresses monocyte adhesion to human umbilical vein ECs. RNA sequencing of TFEB-overexpressed human umbilical vein ECs suggested TFEB inhibits NF-κB (nuclear factor-kappa B) signaling. Indeed, luciferase assay shows TFEB suppresses NF-κB transcriptional activity. Mechanistically, TFEB suppresses IKK (IκB kinase) activity to protect IκB-α from degradation, leading to reduced p65 nuclear translocation. Inhibition of IKK by PS-1145 abolished TFEB silencing-induced inflammation in human umbilical vein ECs. Lastly, we identified KLF2 (Krüppel-like factor 2) upregulates TFEB expression and promoter activity. Laminar flow experiment showed that KLF2 is required for TFEB induction by laminar flow and TFEB is an anti-inflammatory effector downstream of laminar flow-KLF2 signaling in ECs.
Conclusions—
These findings suggest that TFEB exerts anti-inflammatory effects in diabetic mice and such function in ECs is achieved by inhibiting IKK activity and increasing IκBα level to suppress NF-κB activity. KLF2 mediates TFEB upregulation in response to laminar flow.
Polydopamine
(PDA)-coated nanoparticles (NPs) are emerging carriers
of therapeutic agents for nanomedicine applications due to their biocompatibility
and abundant entry to various cell types, yet it remains unknown whether
their cellular entry engages cell-surface receptors. As monomeric
dopamine (DA) is an endogenous ligand of dopamine receptor and raw
ingredient of PDA, we elucidate the interaction between polyethylene
glycol-stabilized, PDA-coated gold NPs (Au@PDA@PEG NPs) and dopamine
receptors, particularly D2 (D2DR). After proving the binding of Au@PDA@PEG
NPs to recombinant and cellular D2DR, we employ antibody blocking,
gene knockdown, and gene overexpression to establish the role of D2DR
in the cellular uptake of Au@PDA@PEG NPs in vitro. By preparing a series of PEG-coated AuNPs that contain different
structural analogues of DA (Au@PEG-X NPs), we demonstrate that catechol
and amine groups collectively enhance the binding of NPs to D2DR and
their cellular uptake. By intravenously injecting Au@PDA@PEG NPs to
Balb/c mice, we reveal their in vivo binding to D2DR
in the liver by competitive inhibition and immunohistochemistry together
with their preferential association to D2DR-rich resident Kupffer
cells by flow cytometry, a result consistent with the profuse expression
of D2DR by resident Kupffer cells. Catechol and amine groups jointly
contribute to the preferential association of NPs to D2DR-rich Kupffer
cells. Our data highlight the importance of D2DR expression and DA-related
functional groups in mediating the cell–nano interactions of
PDA-based nanomedicines.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.