Biology subjects

Alpar, A. T.

Publications and source records attributed to Alpar, A. T..

8 recordsLinked to original sources

bioRxiv2025

Composite biomaterials of polyelectrolyte complex micelle nanoparticles in hyaluronic acid gels enable local, targeted miR-92a inhibition and enhanced angiogenesis in diabetic wound repair

Diabetic wounds are characterized by various cellular deficiencies, particularly insufficient angiogenesis. MicroRNA 92a (miR-92a) is a known factor in diabetic wounds that perpetuates non-healing wound phenotypes by inhibiting angiogenesis. Therefore, its local inhibition at wound sites has therapeutic potential. To achieve this, we combine a nanoparticle formulation of polyelectrolyte complex micelles (PCMs) delivering miR-92a inhibitors with a hyaluronic acid (HA) gel formulation suitable for topical application to wound sites. The nanoparticles, formed by polyelectrolyte complexation of poly(ethylene glycol)-block-poly(L-lysine) with RNA cargo, are functionalized with targeting peptides against vascular cell adhesion molecule 1 (VCAM-1) to improve affinity for inflamed endothelial cells. We demonstrate effective PCM encapsulation and controlled release from gel formulations in vitro and in vivo. These PCMs are taken up in vivo by endothelial cells and exert functional transcriptional effects on miR-92a and its downstream targets. Furthermore, our composite PCM-gel formulation significantly accelerates wound closure in diabetic mouse models and improves angiogenesis, consistent with the known role of miR-92a inhibition in vascular regeneration. This work demonstrates a highly translatable formulation for improved wound healing, and lays the framework for modular nanoparticle-gel systems that can achieve local, cell-targeted RNA delivery. HighlightsPolyelectrolyte complex micelles (PCMs) can be combined with hyaluronic acid gels. VCAM-1 targeted PCMs released from gels are taken up by endothelial cells. PCM-gels deliver miR-92a inhibitors to modulate downstream gene expression in vivo. PCM-gels accelerate wound healing and enhance angiogenesis in diabetic mice.

bioengineering↗

bioRxiv2025

Precision mRNA Nanomedicine for Targeted Vascular Therapies in ARDS and Atherosclerosis

Vascular diseases, including acute respiratory distress syndrome (ARDS) and atherosclerosis, are leading causes of global morbidity and mortality, underscoring the critical need for innovative therapies. While human genetics has uncovered specific molecular mechanisms in endothelial cells that drive acute and chronic vascular inflammation central to these conditions, effective in vivo strategies to spatiotemporally target these disease-causing pathways using therapeutic mRNAs remain limited. Here, we present a modular and tunable nanoparticle platform (PROGRAMMED nanoparticles) engineered to selectively deliver therapeutic mRNAs to target cells with distinct molecular signatures, such as inflamed endothelial cells expressing vascular cell adhesion molecule 1 (VCAM1). This approach restores key genetics-informed endothelial pathways implicated in disease, including the loss of Kruppel-like factor 2 (KLF2) in acute inflammation underlying ARDS and the suppression of phospholipid phosphatase 3 (PLPP3) in chronic inflammation driving atherosclerosis. In multiple preclinical models, these precision mRNA nanomedicine strategies demonstrated compelling therapeutic efficacy. VCAM1-targeting PROGRAMMED nanoparticles delivering KLF2 mRNA to inflamed lung microvascular endothelial cells significantly improved microvascular health and alleviated virus-induced ARDS. Similarly, PLPP3 mRNA delivery by VCAM1-targeting PROGRAMMED nanoparticles attenuated arterial inflammation, slowed atherosclerosis progression, and promoted regression of advanced plaques. This innovative platform offers a transformative approach for spatiotemporal mRNA therapies targeting inflamed endothelial cells, providing a minimally invasive and highly specific strategy to address acute and chronic vascular diseases. Moreover, the modularity of PROGRAMMED nanoparticles, particularly their ability to display diverse targeting motifs, holds substantial potential for addressing a broad spectrum of vascular complications and other diseases that require precise spatiotemporal correction of dysregulated genes.

bioengineering↗

bioRxiv2024

Engineered Flt3L Drives Tolerogenic State to Attenuate Anti-drug Antibody Responses

Immune reactions to protein drugs present substantial challenges to protein replacement for treating congenital diseases and metabolic deficiencies, due to the lack of endogenous tolerance or the protein drugs partial or total non-human origin. We sought to transiently modify the immune environment when the adaptive response to the drug antigen is mounted to lessen future reactions upon continued therapeutic treatment, without modifying the drug itself. Herein, we characterize a recombinant fusion of the cytokine Flt3L to serum albumin and describe a novel pathway of Flt3L-mediated immune regulation. We highlight reduced activation of dendritic cells (DC) as well as an increased frequency of DCs expressing LAP, a TGF-{beta} precursor. These effects in combination with low doses of the exogenous antigen led to less TH2 differentiation. This enabled a tolerance-biasing induction regimen to significantly decrease anti-drug antibodies upon repeated exposure to a clinically used, immunogenic fungal enzyme, rasburicase. This induction regimen reduced the Tfh compartment and increased Tfh cells expressing Foxp3 and PD-L1, suggesting a regulatory response. Overall, we introduce the use of a Flt3L variant as an induction therapeutic to modulate the innate immune response, thereby attenuating the adaptive reaction to antigenic protein drugs and addressing an unmet clinical need.

bioengineering↗

bioRxiv2023

Synthetically mannosylated antigens induce antigen-specific humoral tolerance and reduce anti-drug antibody responses to immunogenic biologics

Immunogenic biologics trigger an anti-drug antibody (ADA) response in patients, which reduces efficacy and increases adverse reactions. Our laboratory has previously shown that targeting protein antigen to the liver microenvironment can reduce antigen-specific T cell responses; herein, we present a strategy to increase delivery of otherwise immunogenic biologics to the liver via conjugation to a synthetic mannose polymer (p(Man)). This delivery leads to reduced antigen-specific T follicular helper cell and B cell responses resulting in diminished ADA production, which is maintained throughout subsequent administrations of the native biologic. We found that p(Man)-antigen treatment impairs the ADA response against recombinant uricase, a highly immunogenic biologic, without a dependence on hapten immunodominance or control by Tregs. We identify increased TCR signaling and increased apoptosis and exhaustion in T cells as effects of p(Man)-antigen treatment via transcriptomic analyses. This modular platform may enhance tolerance to biologics, enabling long-term solutions for an ever-increasing healthcare problem.

bioengineering↗

bioRxiv2022

Engineered collagen-targeting therapeutics reverse lung and kidney fibrosis in mice

Fibrotic diseases are involved in 45% of deaths in the United States. In particular, fibrosis of the kidney and lung are major public health concerns due to their high prevalence and lack of existing treatment options. Here, we harness the pathophysiological features of fibrotic diseases, namely leaky vasculature and aberrant extracellular matrix (ECM) protein deposition (i.e. collagen), to target an anti-fibrotic biologic and a small molecule drug to disease sites of fibrosis, thus improving their therapeutic potential in mouse models of lung and kidney fibrosis. First, we identify and validate collagen-targeting drug delivery systems that preferentially accumulate in the diseased organs: von Willebrand Factors A3 domain (VWF-A3) and decorin-derived collagen-binding peptide-conjugated micelles (CBP-micelles). We then engineer and recombinantly express novel candidate biologic therapies based on the anti-inflammatory cytokine IL-10: A3-IL-10 and A3-Serum Albumin-IL-10 (A3-SA-IL-10). Simultaneously, we stably encapsulate the potential anti-fibrotic water-insoluble drug, rapamycin, in CBP-micelles. We show that these novel formulations of therapeutics bind to collagen in vitro and that their efficacy in mouse models of lung and kidney fibrosis is improved, compared to free, untargeted drugs. Our results demonstrate that collagen-targeted anti-fibrotic drugs may be next generation therapies of high clinical potential.

bioengineering↗

bioRxiv2021

Blocking antibodies against integrin-α3, integrin-αM, and integrin-αMβ2 de-differentiate myofibroblasts and reverse lung and kidney fibroses in a mouse model

Fibrosis is involved in 45% of deaths in the United States, and no treatment exists to reverse the progression of the disease. Myofibroblasts are key to the progression and maintenance of fibrosis. We investigated features of cell adhesion necessary for monocytes to differentiate into myofibroblasts, seeking to identify pathways key to myofibroblast differentiation. Blocking antibodies against integrins 3, M, and M{beta}2 de-differentiate myofibroblasts in vitro, lower the pro-fibrotic secretome of myofibroblasts, and reverse lung and kidney fibrosis in vivo. Decorins collagen-binding peptide directs blocking antibodies (against integrins-3, -M, -M{beta}2) to both fibrotic lungs and fibrotic kidneys, reducing the dose of antibody necessary to reverse fibrosis. This targeted immunotherapy blocking key integrins may be an effective therapeutic for the treatment and reversal of fibrosis. SummaryBlocking antibodies against integrins-3, -M, and -M{beta}2 can be targeted to sites of fibrosis, reverse lung and kidney fibroses, and offer the potential to bring immunotherapy to fibrosis

immunology↗

bioRxiv2021

Generation of potent cellular and humoral immunity against SARS-CoV-2 antigens via conjugation to a polymeric glyco-adjuvant

The SARS-CoV-2 virus has caused an unprecedented global crisis, and curtailing its spread requires an effective vaccine which elicits a diverse and robust immune response. We have previously shown that vaccines made of a polymeric glyco-adjuvant conjugated to an antigen were effective in triggering such a response in other disease models and hypothesized that the technology could be adapted to create an effective vaccine against SARS-CoV-2. The core of the vaccine platform is the copolymer p(Man-TLR7), composed of monomers with pendant mannose or a toll-like receptor 7 (TLR7) agonist. Thus, p(Man-TLR7) is designed to target relevant antigen-presenting cells (APCs) via mannose-binding receptors and then activate TLR7 upon endocytosis. The p(Man-TLR7) construct is amenable to conjugation to protein antigens such as the Spike protein of SARS-CoV-2, yielding Spike-p(Man-TLR7). Here, we demonstrate Spike-p(Man-TLR7) vaccination elicits robust antigen-specific cellular and humoral responses in mice. In adult and elderly wild-type mice, vaccination with Spike-p(Man-TLR7) generates high and long-lasting titers of anti-Spike IgGs, with neutralizing titers exceeding levels in convalescent human serum. Interestingly, adsorbing Spike-p(Man-TLR7) to the depot-forming adjuvant alum, amplified the broadly neutralizing humoral responses to levels matching those in mice vaccinated with formulations based off of clinically-approved adjuvants. Additionally, we observed an increase in germinal center B cells, antigen-specific antibody secreting cells, activated T follicular helper cells, and polyfunctional Th1-cytokine producing CD4+ and CD8+ T cells. We conclude that Spike-p(Man-TLR7) is an attractive, next-generation subunit vaccine candidate, capable of inducing durable and robust antibody and T cell responses.

bioengineering↗

bioRxiv2021

Polymersomes decorated with SARS-CoV-2 spike protein receptor binding domain elicit robust humoral and cellular immunity

A diverse portfolio of SARS-CoV-2 vaccine candidates is needed to combat the evolving COVID-19 pandemic. Here, we developed a subunit nanovaccine by conjugating SARS-CoV-2 Spike protein receptor binding domain (RBD) to the surface of oxidation-sensitive polymersomes. We evaluated the humoral and cellular responses of mice immunized with these surface-decorated polymersomes (RBDsurf) compared to RBD-encapsulated polymersomes (RBDencap) and unformulated RBD (RBDfree), using monophosphoryl lipid A-encapsulated polymersomes (MPLA PS) as an adjuvant. While all three groups produced high titers of RBD-specific IgG, only RBDsurf elicited a neutralizing antibody response to SARS-CoV-2 comparable to that of human convalescent plasma. Moreover, RBDsurf was the only group to significantly increase the proportion of RBD-specific germinal center B cells in the vaccination-site draining lymph nodes. Both RBDsurf and RBDencap drove similarly robust CD4+ and CD8+ T cell responses that produced multiple Th1-type cytokines. We conclude that multivalent surface display of Spike RBD on polymersomes promotes a potent neutralizing antibody response to SARS-CoV-2, while both antigen formulations promote robust T cell immunity.

bioengineering↗