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Biology subjects

Guo, L.-W.

Publications and source records attributed to Guo, L.-W..

5 recordsLinked to original sources

Nature-inspired nanodiscs for lesion-targeted delivery reprogram macrophages and attenuate established abdominal aortic aneurysms

Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease characterized by chronic inflammation and immune dysregulation, with lesional macrophages playing a pivotal role in disease progression. However, effective and safe delivery of immune modulators to macrophages at the site of AAA remains a major clinical challenge. To address this unmet need, we report a nature-inspired nanodisc platform based on high-density lipoproteins for targeted delivery to lesional macrophages, further engineered with a multi-component targeting strategy incorporating an aneurysm-homing peptide and phosphatidylserine lipids. Nanodiscs encapsulating an anti-inflammatory protein kinase R-like endoplasmic reticulum kinase (PERK) inhibitor remarkably attenuated progression of established AAA in an elastase-induced mouse model. Using a combination of in vivo biodistribution and immune profiling approaches, we demonstrate that nanodisc-assisted PERK inhibitor delivery selectively reprograms the local immune microenvironment and attenuates pathological inflammation in AAA disease models. Notably, a single administration achieves sustained therapeutic efficacy with favorable safety profiles, effectively limiting the progression of established AAA in a clinically relevant setting. This work presents a new avenue of designer nanomedicines for targeted immunomodulation and maybe broadly applicable for a wide range of vascular and immune-mediated pathologies.

bioengineering↗

Targeted NAD+ Delivery for Intimal Hyperplasia and Re-endothelialization: A Novel Anti-restenotic Therapy Approach

Endovascular interventions often fail due to restenosis, primarily caused by smooth muscle cell (SMC) proliferation, leading to intimal hyperplasia (IH). Current strategies to prevent restenosis are far from perfect and impose significant collateral damage on the fragile endothelial cell (EC), causing profound thrombotic risks. Nicotinamide adenine dinucleotide (NAD+) is a co-enzyme and signaling substrate implicated in redox and metabolic homeostasis, with a pleiotropic role in protecting against cardiovascular diseases. However, a functional link between NAD+ repletion and the delicate duo of IH and EC regeneration has yet to be established. NAD+ repletion has been historically challenging due to its poor cellular uptake and low bioavailability. We have recently invented the first nanocarrier that enables direct intracellular delivery of NAD+ in vivo. Combining the merits of this prototypic NAD+-loaded calcium phosphate (CaP) nanoparticle (NP) and biomimetic surface functionalization, we created a biomimetic P-NAD+-NP with platelet membrane coating, which enabled an injectable modality that targets IH with excellent biocompatibility. Using human cell primary culture, we demonstrated the benefits of NP-assisted NAD+ repletion in selectively inhibiting the excessive proliferation of aortic SMC, while differentially protecting aortic EC from apoptosis. Moreover, in a rat balloon angioplasty model, a single-dose treatment with intravenously injected P-NAD+-NP immediately post angioplasty not only mitigated IH, but also accelerated the regeneration of EC (re-endothelialization) in vivo in comparison to control groups (i.e., saline, free NAD+ solution, empty CaP-NP). Collectively, our current study provides proof-of-concept evidence supporting the role of targeted NAD+ repletion nanotherapy in managing restenosis and improving re-endothelialization.

pathology↗

BRD2 regulation of sigma-2 receptor expression upon cytosolic cholesterol deprivation

Traditionally a pharmacologic target for antipsychotic treatment, the sigma-2 receptor (S2R) was recently implicated in cholesterol homeostasis. Here we investigated the transcriptional regulation of S2R by the Bromo/ExtraTerminal epigenetic reader family (BETs, including BRD2, 3, 4) upon cholesterol perturbation.\n\nCytosolic cholesterol deprivation was induced using an export blocker of lysosomal cholesterol in ARPE19 cells. This condition upregulated mRNA and protein levels of S2R, and of SREBP2 but not SREBP1, transcription factors key to cholesterol/fatty acid metabolism. Silencing BRD2 but not BRD4 (though widely deemed as a master regulator) or BRD3 prevented S2R upregulation induced by cholesterol deprivation. Silencing SREBP2 but not SREBP1 diminished S2R expression. Furthermore, BRD2 co-immunoprecipitated with the SREBP2 transcription-active N-terminal domain, and chromatin immunoprecipitation-qPCR showed a BRD2 occupancy at the S2R gene promoter.\n\nIn summary, this study reveals a novel BRD2/SREBP2 cooperative regulation of S2R transcription in response to cytosolic cholesterol deprivation, thus shedding new light on epigenetic control of cholesterol biology.

biochemistry↗

A non-canonical role of polo-like kinase-4 in adventitial fibroblast cell type transition

A divergent member of the polo-like kinase family, PLK4 is known for its canonical role in centriole duplication. Its non-canonical function and regulators are poorly defined. Here we investigated PLK4s activation and expression and regulations thereof in rat adventitial fibroblast cell-type transition induced by platelet-derived growth factor (PDGF-AA).\n\nExperiments using siRNA and selective inhibitor (centrinone-B) revealed a role for PLK4 not only in AA-induced proliferation/migration, but also in serum response factor (SRF) activation and smooth muscle -actin expression. PDGFR (receptor) inhibition abrogated AA-stimulated PLK4 activation (phosphorylation) and expression; P38 inhibition (siRNA, inhibitor) downstream of PDGFR also mitigated PLK4 activation. Furthermore, transcription of PLK4 (and PDGFR) was repressed by pan-inhibition of the bromodomain/extraterminal family of chromatin-bookmark readers (BRD2, BRD3, BRD4), an effect determined herein as mainly mediated by BRD4. In vivo, periadventitial administration of centrinone-B reduced collagen content and thickness of the adventitia in a rat model of carotid artery injury.\n\nIn summary, we have identified a non-canonical role for PLK4 in SRF activation and its regulations by BRD4/PDGFR-dominated pathways. Results in this study suggest PLK4 inhibition as a potential anti-fibrotic intervention.

cell biology↗

The BD2 domain of BRD4 is a determinant in EndoMT and vein graft neointima formation

BackgroundVein-graft bypass is commonly performed to overcome atherosclerosis but is limited by high failure rates, principally due to neointimal wall thickening. Recent studies reveal that endothelial-mesenchymal transition (EndoMT) is critical for vein-graft neointima formation. BETs are a family of Bromo/ExtraTerminal domains-containing epigenetic reader proteins (BRD2, BRD3, BRD4). They bind acetylated histones through their unique tandem bromodomains (BD1, BD2), facilitating transcriptional complex formation and cell-state transitions. The role for BETs, including individual BRDs and their unique BDs, is not well understood in EndoMT and neointimal formation.\n\nMethods and ResultsRepression of BRD4 expression abrogated TGF{beta}1-induced EndoMT, with greater effects than BRD2 or BRD3 knockdown. An inhibitor selective for BD2 in all BETs, but not that for BD1, blocked EndoMT. Moreover, expression of a dominant-negative BRD4-specific BD2 fully abolished EndoMT. Concordantly, BRD4 knockdown repressed TGF{beta}1-stimulated increase of ZEB1 protein - a transcription factor integral in EndoMT. In vivo, lentiviral gene transfer of either BRD4 shRNA or dominant negative BRD4-specific BD2 mitigated neointimal development in rat jugular veins grafted to carotid arteries.\n\nConclusionsOur data reveal the BD2 domain of BRD4 as a determinant driving EndoMT in vitro and neointimal formation in vivo. These findings provide new insight into BET biology, while offering prospects of specific BET domain targeting as an approach to limiting neointima and extending vein graft patency.

pathology↗