Synthetic high-density lipoprotein-like nanoparticles potently inhibit cell signaling and production of inflammatory mediators induced by lipopolysaccharide binding Toll-like receptor 4

Nanotechnology-Mediated Immunomodulation Strategy for Inflammation Resolution

Inflammation serves as a common characteristic across a wide range of diseases and plays a vital role in maintaining homeostasis. Inflammation can lead to tissue damage and the onset of inflammatory diseases. Although significant progress is made in anti-inflammation in recent years, the current clinical approaches mainly rely on the systemic administration of corticosteroids and antibiotics, which only provide short-term relief. Recently, immunomodulatory approaches have emerged as promising strategies for facilitating the resolution of inflammation. Especially, the advanced nanosystems with unique biocompatibility and multifunctionality have provided an ideal platform for immunomodulation. In this review, the pathophysiology of inflammation and current therapeutic strategies are summarized. It is mainly focused on the nanomedicines that modulate the inflammatory signaling pathways, inflammatory cells, oxidative stress, and inflammation targeting. Finally, the challenges and opportunities of nanomaterials in addressing inflammation are also discussed. The nanotechnology-mediated immunomodulation will open a new treatment strategy for inflammation therapy.

Inflammatory response of nanoparticles: Mechanisms, consequences, and strategies for mitigation

Numerous nano-dimensioned materials have been generated as a result of several advancements in nanoscale science such as metallic nanoparticles (mNPs) which have aided in the advancement of related research. As a result, several significant nanoscale materials are being produced commercially. It is expected that in the future, products that are nanoscale, like mNPs, will be useful in daily life. Despite certain benefits, widespread use of metallic nanoparticles and nanotechnology has negative effects and puts human health at risk because of their continual accumulation in closed biological systems, along with their complex and diverse migratory and transformation pathways. Once within the human body, nanoparticles (NPs) disrupt the body's natural biological processes and trigger inflammatory responses. These NPs can also affect the immune system by activating separate pathways that either function independently or interact with one another. Cytotoxic effects, inflammatory response, genetic material damage, and mitochondrial dysfunction are among the consequences of mNPs. Oxidative stress and reactive oxygen species (ROS) generation caused by mNPs depend upon a multitude of factors that allow NPs to get inside cells and interact with biological macromolecules and cell organelles. This review focuses on how mNPs cause inflammation and oxidative stress, as well as disrupt cellular signaling pathways that support these effects. In addition, possibilities and problems to be reduced are addressed to improve future research on the creation of safer and more environmentally friendly metal-based nanoparticles for commercial acceptance and sustainable use in medicine and drug delivery.

Synthetic high-density lipoprotein (sHDL): a bioinspired nanotherapeutics for managing periapical bone inflammation

Apical periodontitis (AP) is a dental-driven condition caused by pathogens and their toxins infecting the inner portion of the tooth (i.e., dental pulp tissue), resulting in inflammation and apical bone resorption affecting 50% of the worldwide population, with more than 15 million root canals performed annually in the United States. Current treatment involves cleaning and decontaminating the infected tissue with chemo-mechanical approaches and materials introduced years ago, such as calcium hydroxide, zinc oxide-eugenol, or even formalin products. Here, we present, for the first time, a nanotherapeutics based on using synthetic high-density lipoprotein (sHDL) as an innovative and safe strategy to manage dental bone inflammation. sHDL application in concentrations ranging from 25 µg to 100 µg/mL decreases nuclear factor Kappa B (NF-κB) activation promoted by an inflammatory stimulus (lipopolysaccharide, LPS). Moreover, sHDL at 500 µg/mL concentration markedly decreases in vitro osteoclastogenesis (P < 0.001), and inhibits IL-1α (P = 0.027), TNF-α (P = 0.004), and IL-6 (P < 0.001) production in an inflammatory state. Notably, sHDL strongly dampens the Toll-Like Receptor signaling pathway facing LPS stimulation, mainly by downregulating at least 3-fold the pro-inflammatory genes, such as Il1b, Il1a, Il6, Ptgs2, and Tnf. In vivo, the lipoprotein nanoparticle applied after NaOCl reduced bone resorption volume to (1.3 ± 0.05) mm3 and attenuated the inflammatory reaction after treatment to (1 090 ± 184) cells compared to non-treated animals that had (2.9 ± 0.6) mm3 (P = 0.012 3) and (2 443 ± 931) cells (P = 0.004), thus highlighting its promising clinical potential as an alternative therapeutic for managing dental bone inflammation.

Targeting macrophages with multifunctional nanoparticles to detect and prevent atherosclerotic cardiovascular disease

Despite the emergence of novel diagnostic, pharmacological, interventional, and prevention strategies, atherosclerotic cardiovascular disease remains a significant cause of morbidity and mortality. Nanoparticle (NP)-based platforms encompass diverse imaging, delivery, and pharmacological properties that provide novel opportunities for refining diagnostic and therapeutic interventions for atherosclerosis at the cellular and molecular levels. Macrophages play a critical role in atherosclerosis and therefore represent an important disease-related diagnostic and therapeutic target, especially given their inherent ability for passive and active NP uptake. In this review, we discuss an array of inorganic, carbon-based, and lipid-based NPs that provide magnetic, radiographic, and fluorescent imaging capabilities for a range of highly promising research and clinical applications in atherosclerosis. We discuss the design of NPs that target a range of macrophage-related functions such as lipoprotein oxidation, cholesterol efflux, vascular inflammation, and defective efferocytosis. We also provide examples of NP systems that were developed for other pathologies such as cancer and highlight their potential for repurposing in cardiovascular disease. Finally, we discuss the current state of play and the future of theranostic NPs. Whilst this is not without its challenges, the array of multifunctional capabilities that are possible in NP design ensures they will be part of the next frontier of exciting new therapies that simultaneously improve the accuracy of plaque diagnosis and more effectively reduce atherosclerosis with limited side effects.

Regulation of toll-like receptor (TLR) signaling pathways in atherosclerosis: from mechanisms to targeted therapeutics

Atherosclerosis, one of the life-threatening cardiovascular diseases (CVDs), has been demonstrated to be a chronic inflammatory disease, and inflammatory and immune processes are involved in the origin and development of the disease. Toll-like receptors (TLRs), a class of pattern recognition receptors that trigger innate immune responses by identifying pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), regulate numerous acute and chronic inflammatory diseases. Recent studies reveal that TLRs have a vital role in the occurrence and development of atherosclerosis, including the initiation of endothelial dysfunction, interaction of various immune cells, and activation of a number of other inflammatory pathways. We herein summarize some other inflammatory signaling pathways, protein molecules, and cellular responses associated with TLRs, such as NLRP3, Nrf2, PCSK9, autophagy, pyroptosis and necroptosis, which are also involved in the development of AS. Targeting TLRs and their regulated inflammatory events could be a promising new strategy for the treatment of atherosclerotic CVDs. Novel drugs that exert therapeutic effects on AS through TLRs and their related pathways are increasingly being developed. In this article, we comprehensively review the current knowledge of TLR signaling pathways in atherosclerosis and actively seek potential therapeutic strategies using TLRs as a breakthrough point in the prevention and therapy of atherosclerosis.

Tuning foreign body response with tailor-engineered nanoscale surface modifications: fundamentals to clinical applications

Biomaterials are omnipresent in today's healthcare services and are employed in various applications, including implants, sensors, healthcare accessories, and drug delivery systems. Unfavorable host immunological responses frequently jeopardize the efficacy of biomaterials. As a result, surface modification has received much attention in controlling inflammatory responses since it helps camouflage the biomaterial from the host immune system, influencing the foreign body response (FBR) from protein adsorption to fibrous capsule formation. Surfaces with controlled nanotopography and chemistry, among other surface modification methodologies, have effectively altered the immune response to biomaterials. However, the field is still in its early stages, with only a few studies showing a synergistic effect of surface chemistry and nanotopography on inflammatory and wound healing pathways. Therefore, this review will concentrate on the individual and synergistic effects of surface chemistry and nanotopography on FBR modulation and the molecular processes known to modulate these responses. This review will also provide insights into crucial research gaps and advancements in various tactics for modulating FBR, opening new paths for future research. This will further aid in improving our understanding of the immune response to biomaterials, developing advanced surface modification techniques, designing immunomodulatory biomaterials, and translating discoveries into clinical applications.

Specific Clearance of Lipopolysaccharide from Blood Based on Peptide Bottlebrush Polymer for Sepsis Therapy

Lipopolysaccharide (LPS) is the primary bacterial toxin that is vital to the pathogenesis and progression of sepsis associated with extremely high morbidity and mortality worldwide. However, specific clearance of LPS from circulating blood is highly challenging because of the structural complexity and its variation between/within bacterial species. Herein, a robust strategy based on phage display screening and hemocompatible peptide bottlebrush polymer design for specific clearance of targeted LPS from circulating blood is proposed. Using LPS extracted from Escherichia coli as an example, a novel peptide (HWKAVNWLKPWT) with high affinity (KD < 1.0 nм), specificity, and neutralization activity (95.9 ± 0.1%) against the targeted LPS is discovered via iterative affinity selection coupled with endotoxin detoxification screening. A hemocompatible bottlebrush polymer bearing the short peptide [poly(PEGMEA-co-PEP-1)] exhibits high LPS selectivity to reduce circulating LPS level from 2.63 ± 0.01 to 0.78 ± 0.05 EU mL-1 in sepsis rabbits via extracorporeal hemoperfusion (LPS clearance ratio > 70%), reversing the LPS-induced leukocytopenia and multiple organ damages significantly. This work provides a universal paradigm for developing a highly selective hemoadsorbent library fully covering the LPS family, which is promising to create a new era of precision medicine in sepsis therapy.

Disturbed lipid profile in common variable immunodeficiency - a pathogenic loop of inflammation and metabolic disturbances

The relationship between metabolic and inflammatory pathways play a pathogenic role in various cardiometabolic disorders and is potentially also involved in the pathogenesis of other disorders such as cancer, autoimmunity and infectious diseases. Common variable immunodeficiency (CVID) is the most common primary immunodeficiency in adults, characterized by increased frequency of airway infections with capsulated bacteria. In addition, a large proportion of CVID patients have autoimmune and inflammatory complications associated with systemic inflammation. We summarize the evidence that support a role of a bidirectional pathogenic interaction between inflammation and metabolic disturbances in CVID. This include low levels and function of high-density lipoprotein (HDL), high levels of triglycerides (TG) and its major lipoprotein very low-density lipoprotein (VLDL), and an unfavorable fatty acid (FA) profile. The dysregulation of TG, VLDL and FA were linked to disturbed gut microbiota profile, and TG and VLDL levels were strongly associated with lipopolysaccharides (LPS), a marker of gut leakage in blood. Of note, the disturbed lipid profile in CVID did not include total cholesterol levels or high low-density lipoprotein levels. Furthermore, increased VLDL and TG levels in blood were not associated with diet, high body mass index and liver steatosis, suggesting a different phenotype than in patients with traditional cardiovascular risk such as metabolic syndrome. We hypothesize that these metabolic disturbances are linked to inflammation in a bidirectional manner with disturbed gut microbiota as a potential contributing factor.

Dual Functioned Hexapeptide-Coated Lipid-Core Nanomicelles Suppress Toll-Like Receptor-Mediated Inflammatory Responses through Endotoxin Scavenging and Endosomal pH Modulation

Excessive activation of Toll-like receptor (TLR) signaling pathways and the circulating endotoxin are key players in the pathogenesis of many acute and chronic inflammatory diseases. Regulation of TLR-mediated inflammatory responses by bioactive nanodevices represents a promising strategy for treating these diseases. In searching for novel, clinically applicable nanodevices with potent TLR inhibitory activities, three types of hexapeptide-modified nano-hybrids with different cores of phospholipid nanomicelles, liposomes, and poly(lactic-co-glycolic acid) nanoparticles are constructed. Interestingly, only the peptide-modified lipid-core nanomicelles (M-P12) display potent TLR inhibitory activities. Further mechanistic studies disclose that lipid-core nanomicelles have a generic property to bind to and scavenge lipophilic TLR ligands including lipopolysaccharide to block the ligand-receptor interaction and down-regulate the TLR signaling extracellularly. In addition, the peptide modification enables M-P12 a unique capability to modulate endosomal acidification upon being endocytosed into macrophages, which subsequently regulates the endosomal TLR signal transduction. In an acute lung injury mouse model, intratracheal administration of M-P12 can effectively target lung macrophages and reduce lung inflammation and injuries. This work defines a dual mechanism of action of the peptide-modified lipid-core nanomicelles in regulating TLR signaling, and provides new strategies for the development of therapeutic nanodevices for treating inflammatory diseases.

Cuban Sugar Cane Wax Alcohol Exhibited Enhanced Antioxidant, Anti-Glycation and Anti-Inflammatory Activity in Reconstituted High-Density Lipoprotein (rHDL) with Improved Structural and Functional Correlations: Comparison of Various Policosanols

Policosanols from various sources, such as sugar cane, rice bran, and insects, have been marketed to prevent dyslipidemia, diabetes, and hypertension by increasing the blood high-density lipoproteins cholesterol (HDL-C) levels. On the other hand, there has been no study on how each policosanol influences the quality of HDL particles and their functionality. Reconstituted high-density lipoproteins (rHDLs) with apolipoprotein (apo) A-I and each policosanol were synthesized using the sodium cholate dialysis method to compare the policosanols in lipoprotein metabolism. Each rHDL was compared regarding the particle size and shape, antioxidant activity, and anti-inflammatory activity in vitro and in zebrafish embryos. This study compared four policosanols including one policosanol from Cuba (Raydel^® policosanol) and three policosanols from China (Xi'an Natural sugar cane, Xi'an Realin sugar cane, and Shaanxi rice bran). The synthesis of rHDLs with various policosanols (PCO) from Cuba or China using a molar ratio of 95:5:1:1 with palmitoyloleoyl phosphatidylcholine (POPC): free cholesterol (FC): apoA-I:PCO (wt:wt) showed that rHDL containing Cuban policosanol (rHDL-1) showed the largest particle size and the most distinct particle shape. The rHDL-1 showed a 23% larger particle diameter and increased apoA-I molecular weight with a 1.9 nm blue shift of the maximum wavelength fluorescence than rHDL alone (rHDL-0). Other rHDLs containing Chinese policosanols (rHDL-2, rHDL-3, and rHDL-4) showed similar particle sizes with an rHDL-0 and 1.1-1.3 nm blue shift of wavelength maximum fluorescence (WMF). Among all rHDLs, the rHDL-1 showed the strongest antioxidant ability to inhibit cupric ion-mediated LDL oxidation. The rHDL-1-treated LDL showed the most distinct band intensity and particle morphology compared with the other rHDLs. The rHDL-1 also exerted the highest anti-glycation activity to inhibit the fructose-mediated glycation of human HDL₂ with the protection of apoA-I from proteolytic degradation. At the same time, other rHDLs showed a loss of anti-glycation activity with severe degradation. A microinjection of each rHDL alone showed that rHDL-1 had the highest survivability of approximately 85 ± 3%, with the fastest developmental speed and morphology. In contrast, rHDL-3 showed the lowest survivability, around 71 ± 5%, with the slowest developmental speed. A microinjection of carboxymethyllysine (CML), a pro-inflammatory advanced glycated end product, into zebrafish embryos resulted in severe embryo death of approximately 30 ± 3% and developmental defects with the slowest developmental speed. On the other hand, the phosphate buffered saline (PBS)-injected embryo showed 83 ± 3% survivability. A co-injection of CML and each rHDL into adult zebrafish showed that rHDL-1 (Cuban policosanol) induced the highest survivability, around 85 ± 3%, while rHDL-0 showed 67 ± 7% survivability. In addition, rHDL-2, rHDL-3, and rHDL-4 showed 67 ± 5%, 62 ± 37, and 71 ± 6% survivability, respectively, with a slower developmental speed and morphology. In conclusion, Cuban policosanol showed the strongest ability to form rHDLs with the most distinct morphology and the largest size. The rHDL-containing Cuban policosanol (rHDL-1) showed the strongest antioxidant ability against LDL oxidation, anti-glycation activity to protect apoA-I from degradation, and the highest anti-inflammatory activity to protect embryo death under the presence of CML.

Current Nanomedicine for Targeted Vascular Disease Treatment: Trends and Perspectives

Nanotechnology has been developed to deliver cargos effectively to the vascular system. Nanomedicine is a novel and effective approach for targeted vascular disease treatment including atherosclerosis, coronary artery disease, strokes, peripheral arterial disease, and cancer. It has been well known for some time that vascular disease patients have a higher cancer risk than the general population. During atherogenesis, the endothelial cells are activated to increase the expression of adhesion molecules such as Intercellular Adhesion Molecule 1 (ICAM-1), Vascular cell adhesion protein 1 (VCAM-1), E-selectin, and P-selectin. This biological activation of endothelial cells gives a targetability clue for nanoparticle strategies. Nanoparticle formation has a passive targeting pathway due to the increased adhesion molecule expression on the cell surface as well as increased cell activation. In addition, the VCAM-1-targeting peptide has been widely used to target the inflamed endothelial cells. Biomimetic nanoparticles using platelet and leukocyte membrane fragment strategies have been promising techniques for targeted vascular disease treatment. Cyclodextrin, a natural oligosaccharide with a hydrophobic cavity, increase the solubility of cholesterol crystals at the atherosclerotic plaque site and has been used to deliver the hydrophobic drug statin as a therapeutic in a targeted manner. In summary, nanoparticles decorated with various targeting molecules will be an effective and promising strategy for targeted vascular disease treatment.

Anti-Inflammatory Activity of CIGB-258 against Acute Toxicity of Carboxymethyllysine in Paralyzed Zebrafish via Enhancement of High-Density Lipoproteins Stability and Functionality

Background: Hyperinflammation is frequently associated with the chronic pain of autoimmune disease and the acute death of coronavirus disease (COVID-19) via a severe cytokine cascade. CIGB-258 (Jusvinza®), an altered peptide ligand with 3 kDa from heat shock protein 60 (HSP60), inhibits the systemic inflammation and cytokine storm, but the precise mechanism is still unknown. Objective: The protective effect of CIGB-258 against inflammatory stress of N-ε-carboxymethyllysine (CML) was tested to provide mechanistic insight. Methods: CIGB-258 was treated to high-density lipoproteins (HDL) and injected into zebrafish and its embryo to test a putative anti-inflammatory activity under presence of CML. Results: Treatment of CML (final 200 μM) caused remarkable glycation of HDL with severe aggregation of HDL particles to produce dysfunctional HDL, which is associated with a decrease in apolipoprotein A-I stability and lowered paraoxonase activity. Degradation of HDL3 by ferrous ions was attenuated by a co-treatment with CIGB-258 with a red-shift of the Trp fluorescence in HDL. A microinjection of CML (500 ng) into zebrafish embryos resulted in the highest embryo death rate, only 18% of survivability with developmental defects. However, co-injection of CIGB-258 (final 1 ng) caused the remarkable elevation of survivability around 58%, as well as normal developmental speed. An intraperitoneal injection of CML (final 250 μg) into adult zebrafish resulted acute paralysis, sudden death, and laying down on the bottom of the cage with no swimming ability via neurotoxicity and inflammation. However, a co-injection of CIGB-258 (1 μg) resulted in faster recovery of the swimming ability and higher survivability than CML alone injection. The CML alone group showed 49% survivability, while the CIGB-258 group showed 97% survivability (p < 0.001) with a remarkable decrease in hepatic inflammation up to 50%. A comparison of efficacy with CIGB-258, Infliximab (Remsima®), and Tocilizumab (Actemra®) showed that the CIGB-258 group exhibited faster recovery and swimming ability with higher survivability than those of the Infliximab group. The CIGB-258 group and Tocilizumab group showed the highest survivability, the lowest plasma total cholesterol and triglyceride level, and the infiltration of inflammatory cells, such as neutrophils in hepatic tissue. Conclusion: CIGB-258 ameliorated the acute neurotoxicity, paralysis, hyperinflammation, and death induced by CML, resulting in higher survivability in zebrafish and its embryos by enhancing the HDL structure and functionality.

Design of therapeutic biomaterials to control inflammation

Inflammation plays an important role in the response to danger signals arising from damage to our body and in restoring homeostasis. Dysregulated inflammatory responses occur in many diseases, including cancer, sepsis and autoimmunity. The efficacy of anti-inflammatory drugs, developed for the treatment of dysregulated inflammation, can be potentiated using biomaterials, by improving the bioavailability of drugs and by reducing side effects. In this Review, we first outline key elements and stages of the inflammatory environment and then discuss the design of biomaterials for different anti-inflammatory therapeutic strategies. Biomaterials can be engineered to scavenge danger signals, such as reactive oxygen and nitrogen species and cell-free DNA, in the early stages of inflammation. Materials can also be designed to prevent adhesive interactions of leukocytes and endothelial cells that initiate inflammatory responses. Furthermore, nanoscale platforms can deliver anti-inflammatory agents to inflammation sites. We conclude by discussing the challenges and opportunities for biomaterial innovations in addressing inflammation.

The ancillary effects of nanoparticles and their implications for nanomedicine

Nanoparticles are often engineered as a scaffolding system to combine targeting, imaging and/or therapeutic moieties into a unitary agent. However, mostly overlooked, the nanomaterial itself interacts with biological systems exclusive of application-specific particle functionalization. This nanoparticle biointerface has been found to elicit specific biological effects, which we term 'ancillary effects'. In this Review, we describe the current state of knowledge of nanobiology gleaned from existing studies of ancillary effects with the objectives to describe the potential of nanoparticles to modulate biological effects independently of any engineered function; evaluate how these effects might be relevant for nanomedicine design and functional considerations, particularly how they might be useful to inform clinical decision-making; identify potential clinical harm that arises from adverse nanoparticle interactions with biology; and, finally, highlight the current lack of knowledge in this area as both a barrier and an incentive to the further development of nanomedicine.

Nanotherapies for sepsis by regulating inflammatory signals and reactive oxygen and nitrogen species: New insight for treating COVID-19

SARS-CoV-2 has caused up to 127 million cases of COVID-19. Approximately 5% of COVID-19 patients develop severe illness, and approximately 40% of those with severe illness eventually die, corresponding to more than 2.78 million people. The pathological characteristics of COVID-19 resemble typical sepsis, and severe COVID-19 has been identified as viral sepsis. Progress in sepsis research is important for improving the clinical care of these patients. Recent advances in understanding the pathogenesis of sepsis have led to the view that an uncontrolled inflammatory response and oxidative stress are core factors. However, in the traditional treatment of sepsis, it is difficult to achieve a balance between the inflammation, pathogens (viruses, bacteria, and fungi), and patient tolerance, resulting in high mortality of patients with sepsis. In recent years, nanomaterials mediating reactive oxygen and nitrogen species (RONS) and the inflammatory response have shown previously unattainable therapeutic effects on sepsis. Despite these advantages, RONS and inflammatory response-based nanomaterials have yet to be extensively adopted as sepsis therapy. To the best of our knowledge, no review has yet discussed the pathogenesis of sepsis and the application of nanomaterials. To help bridge this gap, we discuss the pathogenesis of sepsis related to inflammation and the overproduction RONS, which activate pathogen-associated molecular pattern (PAMP)-pattern recognition receptor (PRR) and damage-associated molecular pattern (DAMP)-PRR signaling pathways. We also summarize the application of nanomaterials in the treatment of sepsis. As highlighted here, this strategy could synergistically improve the therapeutic efficacy against both RONS and inflammation in sepsis and may prolong survival. Current challenges and future developments for sepsis treatment are also summarized.

Nanocapsules modify membrane interaction of polymyxin B to enable safe systemic therapy of Gram-negative sepsis

Systemic therapy of Gram-negative sepsis remains challenging. Polymyxin B (PMB) is well suited for sepsis therapy due to the endotoxin affinity and antibacterial activity. However, the dose-limiting toxicity has limited its systemic use in sepsis patients. For safe systemic use of PMB, we have developed a nanoparticulate system, called D-TZP, which selectively reduces the toxicity to mammalian cells but retains the therapeutic activities of PMB. D-TZP consists of an iron-complexed tannic acid nanocapsule containing a vitamin D core, coated with PMB and a chitosan derivative that controls the interaction of PMB with endotoxin, bacteria, and host cells. D-TZP attenuated the membrane toxicity associated with PMB but retained the ability of PMB to inactivate endotoxin and kill Gram-negative bacteria. Upon intravenous injection, D-TZP protected animals from pre-established endotoxemia and polymicrobial sepsis, showing no systemic toxicities inherent to PMB. These results support D-TZP as a safe and effective systemic intervention of sepsis.

Synthetic high-density lipoprotein nanoparticles: Good things in small packages

Medicine has been a great beneficiary of the nanotechnology revolution. Nanotechnology involves the synthesis of functional materials with at least one size dimension between 1 and 100 nm. Advances in the field have enabled the synthesis of bio-nanoparticles that can interface with physiological systems to modulate fundamental cellular processes. One example of a diverse acting nanoparticle-based therapeutic is synthetic high-density lipoprotein (HDL) nanoparticles (NP), which have great potential for treating diseases of the ocular surface. Our group has developed a spherical HDL NP using a gold nanoparticle core. HDL NPs: (i) closely mimic the physical and chemical features of natural HDLs; (ii) contain apoA-I; (iii) bind with high-affinity to SR-B1, which is the major receptor through which HDL modulates cell cholesterol metabolism and controls the selective uptake of HDL cargo into cells; (iv) are non-toxic to cells and tissues; and (v) can be chemically engineered to display nearly any surface or core composition desired. With respect to the ocular surface, topical application of HDL NPs accelerates re-epithelization of the cornea following wounding, attenuates inflammation resulting from chemical burns and/or other stresses, and effectively delivers microRNAs with biological activity to corneal cells and tissues. HDL NPs will be the foundation of a new class of topical eye drops with great translational potential and exemplify the impact that nanoparticles can have in medicine.

Recent advancements of nanomaterial-based therapeutic strategies toward sepsis: bacterial eradication, anti-inflammation, and immunomodulation

Sepsis is a life threatening disease that is caused by a dysregulated host immune response to infection, resulting in tissue damage and organ dysfunction, which account for a high in-hospital mortality (approximately 20%). However, there are still no effective and specific therapeutics for clinical sepsis management. Nanomaterial-based strategies have emerged as promising tools for improving the therapeutic efficacy of sepsis by combating lethal bacterial infection, modulating systemic inflammatory response, preventing multiple organ failure, etc. This review has comprehensively summarized the recent advancements in nanomaterial-based strategies for the management of sepsis and severe complications, in which those nanosystems act either as inherent therapeutics or as nanocarriers for the precise delivery of agents. These formulations mechanically possess antibacterial, anti-inflammatory, immunomodulatory, and anti-oxidative effects, achieving multifunctional synergistic treatment efficacy against sepsis. Furthermore, several cell membrane-derived biomimetic nanoplatforms have been used as decoys to trap and neutralize the pathogenic toxins. The critical role of other adjuvant therapies in sepsis management, including the combination of nanotechnology and stem cell therapy, is also highlighted. Overall, this review provides insights into innovative nanotechnology-based strategies applied in sepsis treatment.

Nanotechnology to the Rescue: Treatment Perspective for the Immune Dysregulation Observed in COVID-19

The study of the use of nanotechnology for drug delivery has been extensive. Nanomedical approaches for therapeutics; drug delivery in particular is superior to conventional methods in that it allows for controlled targeted delivery and release, higher stability, extended circulation time, minimal side-effects, and improved pharmacokinetic clearance (of the drug) form the body, to name a few. The magnitude of COVID-19, the current ongoing pandemic has been severe; it has caused widespread the loss of human life. In individuals with severe COVID-19, immune dysregulation and a rampant state of hyperinflammation is observed. This kind of an immunopathological response is detrimental and results in rapid disease progression, development of secondary infections, sepsis and can be fatal. Several studies have pin-pointed the reason for this immune dysregulation; deviations in the signaling pathways involved in the mediation and control of immune responses. In severe COVID-19 patients, many signaling cascades including JAK/STAT, NF-κB, MAPK/ERK, TGF beta, VEGF, and Notch signaling were found to be either upregulated or inactivated. Targeting these aberrant signaling pathways in conjunction with antiviral therapy will effectuate mitigation of the hyperinflammation, hypercytokinemia, and promote faster recovery. The science of the use of nanocarriers as delivery agents to modulate these signaling pathways is not new; it has already been explored for other inflammatory diseases and in particular, cancer therapy. Numerous studies have evaluated the efficacy and potential of nanomedical approaches to modulate these signaling pathways and have been met with positive results. A treatment regime, that includes nanotherapeutics and antiviral therapies will prove effective and holds great promise for the successful treatment of COVID-19. In this article, we review different nanomedical approaches already studied for targeting aberrant signaling pathways, the host immune response to SARS-CoV-2, immunopathology and the dysregulated signaling pathways observed in severe COVID-19 and the current treatment methods in use for targeting signaling cascades in COVID-19. We then conclude by suggesting that the use of nanomedical drug delivery systems for targeting signaling pathways can be extended to effectively target the aberrant signaling pathways in COVID-19 for best treatment results.

Specific TLR4 Blocking Effect of a Novel 3,4-Dihydropyrimidinone Derivative

Background: Toll-like receptor 4 (TLR4) initiates both innate and adaptive immune responses, which plays an important protective role in self-defense mechanisms. Excessive or inappropriate TLR4 activation causes the development of many autoimmune diseases. Dihydropyrimidinone derivatives are medicinally important molecules with diverse pharmacological activities, including anti-inflammatory activity. The present study focused on novel synthesized 3,4-dihydropyrimidinone derivatives and evaluated their inhibitory effects on TLR4.

Methods: A series of 3,4-dihydropyrimidinone derivatives were recently synthesized and evaluated for their TLR4 inhibition activities and cytotoxic on HEK-Blue^TM hTLR4 cells with the help of QUANTI-Blue assay and MTS assay. Selected compound 3 was analyzed for its molecular docking with TLR4 by using Autodock vina 1.1.2. Its effect on the TLR4 pathway related cytokines was also evaluated in THP-1 cells and human peripheral blood mononuclear cells by using real-time PCR, ELISA and western blot.

Results: Five compounds were synthesized and characterized for effectiveness based on 3,4-dihydropyrimidinone. Compound 3 was found to be the potent hybrid among the synthesized compounds, with high TLR4 inhibition activities and low cytotoxic activities against HEK-Blue^TM hTLR4 cells. Molecular docking analysis showed that two hydrogen bonds between compound 3 and residues Asp209(TLR4) and Asp99(MD-2) mainly contribute to the TLR4 inhibition. In addition, compound 3 suppressed LPS-induced of the mRNA expression of TLR4, IP-10, TNF-α, IL-6, IL-12A, and IL-12B, the protein expression of pIRF3 and pNFκB and the secretion of IP-10, TNF-α in THP-1 cell line. Compound 3 also inhibited LPS-induced expression of TNF-α, IL-6, and IL-1β but increased IP-10 at mRNA levels in human peripheral blood mononuclear cells.

Conclusion: Our study reveals compound 3, a novel 3,4-dihydropyrimidinone derivative, is a potential TLR4 antagonist, which opens up new research avenues for the development of promising therapeutic agents for inflammatory and autoimmune diseases.

Advances in sepsis diagnosis and management: a paradigm shift towards nanotechnology

Sepsis, a dysregulated immune response due to life-threatening organ dysfunction, caused by drug-resistant pathogens, is a major global health threat contributing to high disease burden. Clinical outcomes in sepsis depend on timely diagnosis and appropriate early therapeutic intervention. There is a growing interest in the evaluation of nanotechnology-based solutions for sepsis management due to the inherent and unique properties of these nano-sized systems. This review presents recent advancements in nanotechnology-based solutions for sepsis diagnosis and management. Development of nanosensors based on electrochemical, immunological or magnetic principals provide highly sensitive, selective and rapid detection of sepsis biomarkers such as procalcitonin and C-reactive protein and are reviewed extensively. Nanoparticle-based drug delivery of antibiotics in sepsis models have shown promising results in combating drug resistance. Surface functionalization with antimicrobial peptides further enhances efficacy by targeting pathogens or specific microenvironments. Various strategies in nanoformulations have demonstrated the ability to deliver antibiotics and anti-inflammatory agents, simultaneously, have been reviewed. The critical role of nanoformulations of other adjuvant therapies including antioxidant, antitoxins and extracorporeal blood purification in sepsis management are also highlighted. Nanodiagnostics and nanotherapeutics in sepsis have enormous potential and provide new perspectives in sepsis management, supported by promising future biomedical applications included in the review.

Nanotools for Sepsis Diagnosis and Treatment

Sepsis is one of the leading causes of death worldwide with high mortality rates and a pathological complexity hindering early and accurate diagnosis. Today, laboratory culture tests are the epitome of pathogen recognition in sepsis. However, their consistency remains an issue of controversy with false negative results often observed. Clinically used blood markers, C reactive protein (CRP) and procalcitonin (PCT) are indicators of an acute-phase response and thus lack specificity, offering limited diagnostic efficacy. In addition to poor diagnosis, inefficient drug delivery and the increasing prevalence of antibiotic-resistant microorganisms constitute significant barriers in antibiotic stewardship and impede effective therapy. These challenges have prompted the exploration for alternative strategies that pursue accurate diagnosis and effective treatment. Nanomaterials are examined for both diagnostic and therapeutic purposes in sepsis. The nanoparticle (NP)-enabled capture of sepsis causative agents and/or sepsis biomarkers in biofluids can revolutionize sepsis diagnosis. From the therapeutic point of view, currently existing nanoscale drug delivery systems have proven to be excellent allies in targeted therapy, while many other nanotherapeutic applications are envisioned. Herein, the most relevant applications of nanomedicine for the diagnosis, prognosis, and treatment of sepsis is reviewed, providing a critical assessment of their potentiality for clinical translation.

Targeted reduction of cholesterol uptake in cholesterol-addicted lymphoma cells blocks turnover of oxidized lipids to cause ferroptosis

Normal human cells can either synthesize cholesterol or take it up from lipoproteins to meet their metabolic requirements. In some malignant cells, de novo cholesterol synthesis genes are transcriptionally silent or mutated, meaning that cholesterol uptake from lipoproteins is required for survival. Recent data suggest that lymphoma cells dependent upon lipoprotein-mediated cholesterol uptake are also subject to ferroptosis, an oxygen- and iron-dependent cell death mechanism triggered by accumulation of oxidized lipids in cell membranes unless the lipid hydroperoxidase, glutathione peroxidase 4 (GPX4), reduces these toxic lipid species. To study mechanisms linking cholesterol uptake with ferroptosis and determine the potential role of the high-density lipoprotein (HDL) receptor as a target for cholesterol depleting therapy, we treated lymphoma cell lines known to be sensitive to the reduction of cholesterol uptake with HDL-like nanoparticles (HDL NPs). HDL NPs are a cholesterol-poor ligand that binds to the receptor for cholesterol-rich HDLs, scavenger receptor type B1 (SCARB1). Our data reveal that HDL NP treatment activates a compensatory metabolic response in treated cells toward increased de novo cholesterol synthesis, which is accompanied by nearly complete reduction in expression of GPX4. As a result, oxidized membrane lipids accumulate, leading to cell death through a mechanism consistent with ferroptosis. We obtained similar results in vivo after systemic administration of HDL NPs in mouse lymphoma xenografts and in primary samples obtained from patients with lymphoma. In summary, targeting SCARB1 with HDL NPs in cholesterol uptake-addicted lymphoma cells abolishes GPX4, resulting in cancer cell death by a mechanism consistent with ferroptosis.

Implications of the Human Gut-Brain and Gut-Cancer Axes for Future Nanomedicine

Recent clinical and pathological evidence have implicated the gut microbiota as a nexus for modulating the homeostasis of the human body, impacting conditions from cancer and dementia to obesity and social behavior. The connections between microbiota and human diseases offer numerous opportunities in medicine, most of which have limited or no therapeutic solutions available. In light of this paradigm-setting trend in science, this review aims to provide a comprehensive and timely summary of the mechanistic pathways governing the gut microbiota and their implications for nanomedicines targeting cancer and neurodegenerative diseases. Specifically, we discuss in parallel the beneficial and pathogenic relationship of the gut microbiota along the gut-brain and gut-cancer axes, elaborate on the impact of dysbiosis and the gastrointestinal corona on the efficacy of nanomedicines, and highlight a molecular mimicry that manipulates the universal cross-β backbone of bacterial amyloid to accelerate neurological disorders. This review further offers a forward-looking section on the rational design of cancer and dementia nanomedicines exploiting the gut-brain and gut-cancer axes.

A highly efficient hybrid peptide ameliorates intestinal inflammation and mucosal barrier damage by neutralizing lipopolysaccharides and antagonizing the lipopolysaccharide-receptor interaction

Intestinal inflammatory disorders, such as inflammatory bowel disease, are major contributors to mortality and morbidity in humans and animals worldwide. While some native peptides have great potential as therapeutic agents against intestinal inflammation, potential cytotoxicity, anti-inciting action, and suppression of anti-inflammatory activity may limit their development as anti-inflammatory agents. Peptide hybridization is an effective approach for the design and engineering of novel functional peptides because hybrid peptides combine the advantages and benefits of various native peptides. In the present study, a novel hybrid anti-inflammatory peptide that combines the active center of Cecropin A (C) and the core functional region of LL-37 (L) was designed [C-L peptide; C (1-8)-L (17-30)] through in silico analysis to reduce cytotoxicity and improve the anti-inflammatory activity of the parental peptides. The resulting C-L peptide exhibited lower cytotoxicity than either C or L peptides alone. C-L also exerted a protective effect against lipopolysaccharide (LPS)-induced inflammatory responses in RAW264.7 macrophages and in the intestines of a mouse model. The hybrid peptide exhibited increased anti-inflammatory activity compared to the parental peptides. C-L plays a role in protecting intestinal tissue from damage, LPS-induced weight loss, and leukocyte infiltration. In addition, C-L reduces the expression levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), IL-1β, and interferon-gamma (IFN-γ), as well as reduces cell apoptosis. It also reduced mucosal barrier damage caused by LPS. The anti-inflammatory effects of the hybrid peptide were mainly attributed to its LPS-neutralizing activity and antagonizing the activation of LPS-induced Toll-like receptor 4-myeloid differentiation factor 2 (TLR4/MD2). The peptide also affected the TLR4-(nuclear factor κB) signaling pathway, modulating the inflammatory response upon LPS stimulation. Collectively, these findings suggest that the newly designed peptide, C-L, could be developed into a novel anti-inflammatory agent for animals or humans.

HDL nanoparticles have wound healing and anti-inflammatory properties and can topically deliver miRNAs

microRNAs regulate numerous biological processes, making them potential therapeutic agents. Problems with delivery and stability of these molecules have limited their usefulness as treatments. We demonstrate that synthetic high-density lipoprotein nanoparticles (HDL NPs) topically applied to the intact ocular surface are taken up by epithelial and stromal cells. microRNAs complexed to HDL NPs (miR-HDL NPs) are similarly taken up by cells and tissues and retain biological activity. Topical treatment of diabetic mice with either HDL NPs or miR-HDL NPs significantly improved corneal re-epithelialization following wounding compared with controls. Mouse corneas with alkali burn-induced inflammation, topically treated with HDL NPs, displayed clinical, morphological and immunological improvement. These results should yield a novel HDL NP-based eye drop for patients with compromised wound healing ability (diabetics) and/or corneal inflammatory diseases (e.g. dry eye).

Biomaterial-Driven Immunomodulation: Cell Biology-Based Strategies to Mitigate Severe Inflammation and Sepsis

Inflammation is an essential component of a wide variety of disease processes and oftentimes can increase the deleterious effects of a disease. Finding ways to modulate this essential immune process is the basis for many therapeutics under development and is a burgeoning area of research for both basic and translational immunology. In addition to developing therapeutics for cellular and molecular targets, the use of biomaterials to modify innate and adaptive immune responses is an area that has recently sparked significant interest. In particular, immunomodulatory activity can be engineered into biomaterials to elicit heightened or dampened immune responses for use in vaccines, immune tolerance, or anti-inflammatory applications. Importantly, the inherent physicochemical properties of the biomaterials play a significant role in determining the observed effects. Properties including composition, molecular weight, size, surface charge, and others affect interactions with immune cells (i.e., nano-bio interactions) and allow for differential biological responses such as activation or inhibition of inflammatory signaling pathways, surface molecule expression, and antigen presentation to be encoded. Numerous opportunities to open new avenues of research to understand the ways in which immune cells interact with and integrate information from their environment may provide critical solutions needed to treat a variety of disorders and diseases where immune dysregulation is a key inciting event. However, to elicit predictable immune responses there is a great need for a thorough understanding of how the biomaterial properties can be tuned to harness a designed immunological outcome. This review aims to systematically describe the biological effects of nanoparticle properties-separate from additional small molecule or biologic delivery-on modulating innate immune cell responses in the context of severe inflammation and sepsis. We propose that nanoparticles represent a potential polypharmacological strategy to simultaneously modify multiple aspects of dysregulated immune responses where single target therapies have fallen short for these applications. This review intends to serve as a resource for immunology labs and other associated fields that would like to apply the growing field of rationally designed biomaterials into their work.

Infection-induced innate antimicrobial response disorders: from signaling pathways and their modulation to selected biomarkers

Severe infections are a major public health problem responsible for about 40-65% of hospitalizations in intensive care units (ICU). The high mortality (30-50%) of persons diagnosed with severe infection is caused by largely unknown mechanisms of sepsis-induced immune system response. Severe infections with dynamic progress are accompanied with SIRS (systemic inflammatory reaction syndrome) and CARS (compensatory anti-inflammatory response syndrome), and require a biological treatment appropriate to the phase of immune response. The mechanisms responsible for severe infection related to immune system response particularly attract extensive interest of non-specific defense mechanisms, including signaling pathways of Toll-like receptors (mainly TLR4 and TLR2) that recognize distinct pathogen-associated molecular patterns (PAMP) and play a critical role in innate immune response. There are attempts of treatment, followed by blocking ligand binding with TLR or modulation of intracellular signaling pathways, to inhibit signal transduction. Moreover, researches regarding new and more efficient diagnostics biomarkers were mostly focused on indicators related to innate response to infection as well as connections of pro-inflammatory response with anti-inflammatory response.According to these studies, in case of ICU septic patients with high-risk of mortality, the solution for the problem will require mainly early immune and genetic diagnostics (e.g. cytokines, microRNA, cluster of differentiation-64 [CD64], triggering receptor expressed on myeloid cells-1 [TREM-1], and high mobility group box 1 protein [HMGB1]).

Targeting siRNA in colorectal cancer therapy: Nanotechnology comes into view

Colorectal cancer (CRC) is known as one of the most important causes of death and mortality worldwide. Although several efforts have been made for finding new therapies, no achievements have been made in this area. Multidrug resistance (MDR) mechanisms are one of the key factors that could lead to the failure of chemotherapy. Moreover, it has been shown that various chemotherapy drugs are associated with several side effects. Hence, it seems that finding new drugs or new therapeutic platforms is required. Among different therapeutic approaches, utilization of nanoparticles (NPs) for targeting a variety of molecules such as siRNAs are associated with good results for the treatment of CRC. Targeting siRNA-mediated NPs could turn off the effects of oncogenes and MDR-related genes. In the current study, we summarized various siRNAs targeted by NPs which could be used for the treatment of CRC. Moreover, we highlighted other routes such as liposome for targeting siRNAs in CRC therapy.

End-Stage Renal Disease-Associated Gut Bacterial Translocation: Evolution and Impact on Chronic Inflammation and Acute Rejection After Renal Transplantation

Chronic inflammation in end-stage renal disease (ESRD) is partly attributed to gut bacterial translocation (GBT) due to loss of intestinal epithelium integrity. Increased levels of circulating lipopolysaccharide (LPS) –a surrogate marker of GBT– contribute to maintain a chronic inflammatory state. However, circulating LPS can be neutralized by lipoproteins and transported to the liver for elimination. While ESRD-associated GBT has been widely described, less is known about its changes and impact on clinical outcome after kidney transplantation (KT). One hundred and forty-six renal transplant recipients with serum samples obtained immediately before and 1 year after transplantation (1-Year post KT) were included. Intestinal epithelium integrity (iFABP), total LPS (by measuring 3-hydroxymyristate), LPS activity (biologically active LPS measured by the LAL assay), inflammatory biomarkers (sCD14 and cytokines), lipoproteins and LPS-binding proteins (LBP and phospholipid transfer protein [PLTP] activity) were simultaneously measured. At 1-Year post KT, iFABP decreased but remained higher than in normal volunteers. Total LPS concentration remained stable while LPS activity decreased. Inflammation biomarkers decreased 1-Year post KT. We concomitantly observed an increase in lipoproteins. Higher sCD14 levels before transplantation was associated with lower incidence of acute rejection. Although GBT remained stable after KT, the contemporary increase in lipoproteins could bind circulating LPS and contribute concomitantly to neutralization of LPS activity, as well as improvement in ESRD-associated chronic inflammation. Chronic exposure to LPS in ESRD could promote endotoxin tolerance and explain why patients with higher pre-transplant sCD14 are less prompt to develop acute rejection after transplantation.

Cargo-less nanoparticles program innate immune cell responses to toll-like receptor activation

Developing biomaterials to control the responsiveness of innate immune cells represents a clinically relevant approach to treat diseases with an underlying inflammatory basis, such as sepsis. Sepsis can involve activation of Toll-like receptor (TLR) signaling, which activates numerous inflammatory pathways. The breadth of this inflammation has limited the efficacy of pharmacological interventions that target a single molecular pathway. Here, we developed cargo-less particles as a single-agent, multi-target platform to elicit broad anti-inflammatory action against innate immune cells challenged by multiple TLR agonists. The particles, prepared from poly(lactic-co-glycolic acid) (PLGA) and poly(lactic acid) (PLA), displayed potent molecular weight-, polymer composition-, and charge-dependent immunomodulatory properties, including downregulation of TLR-induced costimulatory molecule expression and cytokine secretion. Particles prepared using the anionic surfactant poly(ethylene-alt-maleic acid) (PEMA) significantly blunted the responses of antigen presenting cells to TLR4 (lipopolysaccharide) and TLR9 (CpG-ODN) agonists, demonstrating broad inhibitory activity to both extracellular and intracellular TLR ligands. Interestingly, particles prepared using poly(vinyl alcohol) (PVA), a neutrally-charged surfactant, only marginally inhibited inflammatory cytokine secretions. The biochemical pathways modulated by particles were investigated using TRanscriptional Activity CEll aRrays (TRACER), which implicated IRF1, STAT1, and AP-1 in the mechanism of action for PLA-PEMA particles. Using an LPS-induced endotoxemia mouse model, administration of PLA-PEMA particles prior to or following a lethal challenge resulted in significantly improved mean survival. Cargo-less particles affect multiple biological pathways involved in the development of inflammatory responses by innate immune cells and represent a potentially promising therapeutic strategy to treat severe inflammation.

Size-dependent anti-inflammatory activity of a peptide-gold nanoparticle hybrid in vitro and in a mouse model of acute lung injury

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a life-threatening condition of critically-ill patients, characterized by overwhelming inflammatory responses in the lung. Multiple lines of evidence suggest that the excessive activation of Toll-like receptor 4 (TLR4) plays an important role in this detrimental lung inflammation. Recently, we developed a unique class of peptide-gold nanoparticle (GNP) hybrids that act as potent nano-inhibitors of TLR4 signaling by modulating the process of endosomal acidification. In this study, we aimed to identify the key physiochemical factors that could further strengthen the anti-inflammatory activity of these nano-inhibitors, including the nanoparticle size, the density of peptides coating the nanoparticle surface, as well as the number of the effective amino acid phenylalanine (F) residues in the peptide sequence. Among these factors, we found that the nanoparticle size could significantly affect the TLR4 inhibition. Specifically, the peptide-GNP hybrids with a GNP core of 20 nm (P12(G20)) exhibited the most potent inhibitory activity on TLR4 activation and its downstream cytokine production among those with a GNP core of 13 nm (P12(G13)) and 5 nm (P12(G5)) in THP-1 cell-derived macrophages. This size-dependent anti-inflammatory effect of the hybrid P12 was also observed in a lipopolysaccharide (LPS)-induced mouse model of ALI. It was found that P12(G20) was superior to P12(G13) in prolonging the survival of mice experiencing lethal LPS challenge, decreasing the acute lung inflammation, and alleviating diffuse alveolar damage in the lungs. Interestingly, P12(G20) could also promote long-term tolerance to endotoxin. Detailed mechanistic studies demonstrated that when compared to the smaller P12(G13), the larger P12(G20) had higher cellular uptake and a stronger endosomal pH buffering capacity, contributing to its enhanced therapeutic effects on reducing TLR4 activation in vitro and in vivo. Overall, this study suggests that nanoparticle size is one key factor determining the anti-inflammatory potency of the peptide-GNP hybrids, and the hybrid P12 may serve as a promising, novel class of nanotherapeutics for modulating TLR signaling to treat ALI/ARDS. STATEMENT OF SIGNIFICANCE: We have developed a new class of nanoparticle-based inhibitors (i.e., peptide-GNP hybrids) targeting TLR4 signaling in macrophages. Through evidence-based engineering of the nanoparticle size, surface peptide ligand density and effective amino acid (phenylalanine, F) chain length, we identified a peptide-GNP hybrid, P12(G20), with enhanced anti-inflammatory activity. Specifically, P12(G20) was more potent in reducing inflammation in THP-1 cell-derived macrophages and in a LPS-induced ALI mouse model. More interestingly, P12(G20) facilitated long-term protection against lethal LPS challenge in vivo and induced endotoxin tolerance in vitro. We anticipate that these new hybrids would serve as the next generation anti-inflammatory nano-therapeutics for the treatment of ALI/ARDS or other acute and chronic inflammatory diseases.

Lipopolysaccharide (LPS) Aggravates High Glucose- and Hypoxia/Reoxygenation-Induced Injury through Activating ROS-Dependent NLRP3 Inflammasome-Mediated Pyroptosis in H9C2 Cardiomyocytes

Diabetes aggravates myocardial ischemia-reperfusion (I/R) injury because of the combination effects of changes in glucose and lipid energy metabolism, oxidative stress, and systemic inflammatory response. Studies have indicated that myocardial I/R may coincide and interact with sepsis and inflammation. However, the role of LPS in hypoxia/reoxygenation (H/R) injury in cardiomyocytes under high glucose conditions is still unclear. Our objective was to examine whether lipopolysaccharide (LPS) could aggravate high glucose- (HG-) and hypoxia/reoxygenation- (H/R-) induced injury by upregulating ROS production to activate NLRP3 inflammasome-mediated pyroptosis in H9C2 cardiomyocytes. H9C2 cardiomyocytes were exposed to HG (30 mM) condition with or without LPS, along with caspase-1 inhibitor (Ac-YVAD-CMK), inflammasome inhibitor (BAY11-7082), ROS scavenger N-acetylcysteine (NAC), or not for 24 h, then subjected to 4 h of hypoxia followed by 2 h of reoxygenation (H/R). The cell viability, lactate dehydrogenase (LDH) release, caspase-1 activity, and intracellular ROS production were detected by using assay kits. The incidence of pyroptosis was detected by calcein-AM/propidium iodide (PI) double staining kit. The concentrations of IL-1β and IL-18 in the supernatants were assessed by ELISA. The mRNA levels of NLRP3, ASC, and caspase-1 were detected by qRT-PCR. The protein levels of NF-κB p65, NLRP3, ASC, cleaved caspase-1 (p10), IL-1β, and IL-18 were detected by western blot. The results indicated that pretreatment LPS with 1 μg/ml not 0.1 μg/ml could efficiently aggravate HG and H/R injury by activating NLRP3 inflammasome to mediate pyroptosis in H9C2 cells, as evidenced by increased LDH release and decreased cell viability in the cells, and increased expression of NLRP3, ASC, cleaved caspase-1 (p10), IL-1β, and IL-18. Meanwhile, Ac-YVAD-CMK, BAY11-7082, or NAC attenuated HG- and H/R-induced H9C2 cell injury with LPS stimulated by reversing the activation of NLRP3 inflammasome-mediated pyroptosis. In conclusion, LPS could increase the sensitivity of H9C2 cells to HG and H/R and aggravated HG- and H/R-induced H9C2 cell injury by promoting ROS production to induce NLRP3 inflammasome-mediated pyroptosis.

The Inhibitory Role of M2000 (β-D-Mannuronic Acid) on Expression of Toll-like Receptor 2 and 4 in HT29 Cell Line

BACKGROUND/OBJECTIVES

Anti-inflammatory agents play a crucial role in controlling inflammatory diseases such as Inflammatory Bowel Disease (IBD) but their use is restricted due to their vast side effects. M2000 (β-D-mannuronic acid) is a new immunomodulatory drug. According to the capacity of M2000 in suppressing some molecules involved in Toll Like Receptors (TLRs) signaling and reducing oxidative stress we hypothesize that, this molecule may have a potential role in decreasing inflammatory responses in IBD. The aim of this study was to evaluate the cytotoxicity of M2000 and its effect on the gene expression of TLR2 and TLR4.

METHODS

HEK293 cell line was grown and divided into 96-well cell plate and MTT assay was performed. HT29 cells were cultured and treated with low and high doses of M2000. Total RNA was extracted and cDNA synthesized and quantitative real-time PCR was done to quantify the TLR2 and TLR4 mRNA expression.

RESULTS

We found that M2000 at the concentration of ≤ 1000µg/ml had no obvious cytotoxicity effect on the HEK293 cells. Also, low and high doses of M2000 could significantly down-regulate both TLR2 and TLR4 mRNA expression. Moreover, a significant reduction in gene expression of TLR2 and TLR4 in an inflammatory condition resulted in high doses of M2000 in the presence of LPS.

CONCLUSION

Our study which was conducted in colonic epithelial cell model, shows that M2000 can be considered as a new anti-inflammatory agent in IBD. However, more comprehensive experimental and clinical studies are required to recognize the molecular mechanism of M2000 and also its safety and efficacy.

Arsenic Trioxide-Coated Stent Is an Endothelium-Friendly Drug Eluting Stent

An ideal vascular stent would both inhibit in-stent restenosis (ISR) and promote rapid re-endothelialization. In the current study, the performance of arsenic trioxide (ATO)-drug eluting stent (AES) is compared with the bare metal stent, poly-lactic-co-glycolic acid-coating metal stent, and rapamycin-drug eluting stent (RES). In vivo AES is shown to prevent neointimal hyperplasia more efficiently than the others when implanted into the carotid arteries of rabbits. Moreover, AES promotes endothelial cells proliferation and re-endothelialization more quickly than RES. In vitro ATO exposure significantly increases the viability, proliferation, adhesion, and spreading of primary porcine coronary artery endothelial cells (PCAECs), which are critical for endothelialization. However, ATO exposure reduces the viability of porcine coronary artery smooth muscle cells (PCASMCs). The evaluation of mitochondrial morphology, membrane potential, and function demonstrates that ATO at 2 µmol L^-1 causes enlargement of the mitochondrion, enhancement of mitochondrial membrane potential, and adenosine triphosphate (ATP) production in PCAECs but not in PCASMCs. Thus, both in vivo and in vitro studies demonstrate that AES is an effective strategy for rapid re-endothelialization and inhibition of ISR.

Nitric Oxide-Delivering High-Density Lipoprotein-like Nanoparticles as a Biomimetic Nanotherapy for Vascular Diseases

Disorders of blood vessels cause a range of severe health problems. As a powerful vasodilator and cellular second messenger, nitric oxide (NO) is known to have beneficial vascular functions. However, NO typically has a short half-life and is not specifically targeted. On the other hand, high-density lipoproteins (HDLs) are targeted natural nanoparticles (NPs) that transport cholesterol in the systemic circulation and whose protective effects in vascular homeostasis overlap with those of NO. Evolving the AuNP-templated HDL-like nanoparticles (HDL NPs), a platform of bioinspired HDL, we set up a targeted biomimetic nanotherapy for vascular disease that combines the functions of NO and HDL. A synthetic S-nitrosylated (SNO) phospholipid (1,2-dipalmitoyl-sn-glycero-3-phosphonitrosothioethanol) was synthesized and assembled with S-containing phospholipids and the principal protein of HDL, apolipoprotein A-I, to construct NO-delivering HDL-like particles (SNO HDL NPs). SNO HDL NPs self-assemble under mild conditions similar to natural processes, avoiding the complex postassembly modification needed for most synthetic NO-release nanoparticles. In vitro data demonstrate that the SNO HDL NPs merge the functional properties of NO and HDL into a targeted nanocarrier. Also, SNO HDL NPs were demonstrated to reduce ischemia/reperfusion injury in vivo in a mouse kidney transplant model and atherosclerotic plaque burden in a mouse model of atherosclerosis. Thus, the synthesis of SNO HDL NPs provides not only a bioinspired nanotherapy for vascular disease but also a foundation to construct diversified multifunctional platforms based on HDL NPs in the future.

Core hydrophobicity tuning of a self-assembled particle results in efficient lipid reduction and favorable organ distribution

Atherosclerosis, the deadliest disease in the United States, arises due to the build up of plaques in the arteries as a result of excessive cholesterol deposition and an impaired cholesterol removal process. High density lipoproteins (HDL), popularly known as "good cholesterol", are naturally occurring nano-sized particles that, along with apolipoproteins, are deployed to maintain cholesterol homeostasis in the body. Both cholesterol efflux, from the fat-laden macrophages in the arteries, and intracellular lipid transport, to deliver cholesterol to the mitochondria of liver cells for metabolism, hold key responsibilities to maintain healthy lipid levels inside the body. We designed a library of nine mitochondria targeted polymer-lipid hybrid nanoparticles (NPs), comprised of completely synthetic yet biodegradable components, that are capable of performing HDL-like functions. Using this library, we optimized a superior mitochondria targeted NP candidate, which can show favourable organ distribution, therapeutic potential, and non-toxic properties. Two targeted NP formulations with optimum NP size, zeta potential, and cholesterol binding and release properties were identified. Lipid reduction and anti-oxidative properties of these two NPs demonstrated cholesterol removal ability. In vivo therapeutic evaluation of the targeted-NP formulations in apolipoprotein E knockout (apoE^-/^-) mice indicated lipid reduction and anti-inflammatory properties compared to non-targeted NPs. This synthetic targeted NP with potential abilities to participate in both extra- and intracellular cholesterol transport might potentiate therapeutic interventions for heart diseases.

Sequence and functional analysis of intestinal alkaline phosphatase from Lateolabrax maculatus

Alkaline phosphatases (Alps) belong to a class of phosphate transferases that dephosphorylate lipopolysaccharide (LPS), adenosine triphosphate, and nucleotides. In this study, a 1874-base pair (bp) intestinal alp cDNA sequence was cloned from Lateolabrax maculatus and designated as Lm-alpi. It contained a 1611 bp open reading frame which encoded a protein with 537 amino acids. Protein sequence alignment showed that Lm-AlpI shared 29.8-79.8% identity with its homologs. Lm-AlpI catalytic sites contained three metal ion sites (two Zn²⁺ and one Mg²⁺), referring to D73, H184, D348, H349, H352, H464, D389, and H390 residues, which are essential for enzymatic activity and conservation in different organisms. Two predicted disulfide bonds in Lm-AlpI were composed of four cysteines (C152-C214 and C499-C506), which were homologous to those of mammals. Immunohistochemical staining revealed that Lm-AlpI was mainly expressed on the mucosal surface of the gastrointestinal tract, including stomach, intestine, and gastric cecum. Lm-AlpI was mainly located on the plasma membrane of transiently transfected HeLa cells. The mRNA of Lm-alpi was mainly expressed in the intestine, and its expression levels gradually increased after LPS treatment and further increased by 1.81-fold after 48 h. After desalting culture, the relative mRNA expression level of Lm-alpi decreased at 30 and 50 days after hatching (DAH) and then returned to normal levels at 70 DAH. Further experiments demonstrated that the enzyme activity of Lm-AlpI exhibited an expression pattern similar to that of the mRNA expression of Lm-alpi after LPS treatment and desalting culture. This study provided valuable information on the Lm-AlpI functions associated with the mucosal immunity and salinity adaptation of L. maculatus.

Effects of engineered nanoparticles on the innate immune system

Engineered nanoparticles (NPs) have broad applications in industry and nanomedicine. When NPs enter the body, interactions with the immune system are unavoidable. The innate immune system, a non-specific first line of defense against potential threats to the host, immediately interacts with introduced NPs and generates complicated immune responses. Depending on their physicochemical properties, NPs can interact with cells and proteins to stimulate or suppress the innate immune response, and similarly activate or avoid the complement system. NPs size, shape, hydrophobicity and surface modification are the main factors that influence the interactions between NPs and the innate immune system. In this review, we will focus on recent reports about the relationship between the physicochemical properties of NPs and their innate immune response, and their applications in immunotherapy.

Lipopolysaccharide enters the rat brain by a lipoprotein-mediated transport mechanism in physiological conditions

Physiologically, lipopolysaccharide (LPS) is present in the bloodstream and can be bound to several proteins for its transport (i.e.) LPS binding protein (LBP) and plasma lipoproteins). LPS receptors CD14 and TLR-4 are constitutively expressed in the Central Nervous System (CNS). To our knowledge, LPS infiltration in CNS has not been clearly demonstrated. A naturalistic experiment with healthy rats was performed to investigate whether LPS is present with its receptors in brain. Immunofluorescences showed that lipid A and core LPS were present in circumventricular organs, choroid plexus, meningeal cells, astrocytes, tanycytes and endothelial cells. Co-localization of LPS regions with CD14/TLR-4 was found. The role of lipoprotein receptors (SR-BI, ApoER2 and LDLr) in the brain as targets for a LPS transport mechanism by plasma apolipoproteins (i.e. ApoAI) was studied. Co-localization of LPS regions with these lipoproteins markers was observed. Our results suggest that LPS infiltrates in the brain in physiological conditions, possibly, through a lipoprotein transport mechanism, and it is bound to its receptors in blood-brain interfaces.

Screening Bioactive Nanoparticles in Phagocytic Immune Cells for Inhibitors of Toll-like Receptor Signaling

Pharmacological regulation of Toll-like receptor (TLR) responses holds great promise in the treatment of many inflammatory diseases. However, there have been limited compounds available so far to attenuate TLR signaling and there have been no clinically approved TLR inhibitors (except the anti-malarial drug hydroxychloroquine) in clinical use. In light of rapid advances in nanotechnology, manipulation of immune responsiveness using nano-devices may provide a new strategy to treat these diseases. Herein, we present a high throughput screening method for quickly identifying novel bioactive nanoparticles that inhibit TLR signaling in phagocytic immune cells. This screening platform is built on THP-1 cell-based reporter cells with colorimetric and luciferase assays. The reporter cells are engineered from the human THP-1 monocytic cell line by stable integration of two inducible reporter constructs. One expresses a secreted embryonic alkaline phosphatase (SEAP) gene under the control of a promoter inducible by the transcription factors NF-κB and AP-1, and the other expresses a secreted luciferase reporter gene under the control of promoters inducible by interferon regulatory factors (IRFs).Upon TLR stimulation, the reporter cells activate transcription factors and subsequently produce SEAP and/or luciferase, which can be detected using their corresponding substrate reagents. Using a library of peptide-gold nanoparticle (GNP) hybrids established in our previous studies as an example, we identified one peptide-GNP hybrid that could effectively inhibit the two arms of TLR4 signaling cascade triggered by its prototypical ligand, lipopolysaccharide (LPS). The findings were validated by standard biochemical techniques including immunoblotting. Further analysis established that this lead hybrid had a broad inhibitory spectrum, acting on multiple TLR pathways, including TLR2, 3, 4, and 5. This experimental approach allows a rapid assessment of whether a nanoparticle (or other therapeutic compounds) can modulate specific TLR signaling in phagocytic immune cells.

Inhibition of Toll-Like Receptor Signaling as a Promising Therapy for Inflammatory Diseases: A Journey from Molecular to Nano Therapeutics

The recognition of invading pathogens and endogenous molecules from damaged tissues by toll-like receptors (TLRs) triggers protective self-defense mechanisms. However, excessive TLR activation disrupts the immune homeostasis by sustained pro-inflammatory cytokines and chemokines production and consequently contributes to the development of many inflammatory and autoimmune diseases, such as systemic lupus erythematosus (SLE), infection-associated sepsis, atherosclerosis, and asthma. Therefore, inhibitors/antagonists targeting TLR signals may be beneficial to treat these disorders. In this article, we first briefly summarize the pathophysiological role of TLRs in the inflammatory diseases. We then focus on reviewing the current knowledge in both preclinical and clinical studies of various TLR antagonists/inhibitors for the prevention and treatment of inflammatory diseases. These compounds range from conventional small molecules to therapeutic biologics and nanodevices. In particular, nanodevices are emerging as a new class of potent TLR inhibitors for their unique properties in desired bio-distribution, sustained circulation, and preferred pharmacodynamic and pharmacokinetic profiles. More interestingly, the inhibitory activity of these nanodevices can be regulated through precise nano-functionalization, making them the next generation therapeutics or “nano-drugs.” Although, significant efforts have been made in developing different kinds of new TLR inhibitors/antagonists, only limited numbers of them have undergone clinical trials, and none have been approved for clinical uses to date. Nevertheless, these findings and continuous studies of TLR inhibition highlight the pharmacological regulation of TLR signaling, especially on multiple TLR pathways, as future promising therapeutic strategy for various inflammatory and autoimmune diseases.

Endosomal pH modulation by peptide-gold nanoparticle hybrids enables potent anti-inflammatory activity in phagocytic immune cells

Toll-like receptor (TLR) signaling plays a central role in the pathophysiology of many acute and chronic human inflammatory diseases, and pharmacological regulation of TLR responses is anticipated to be beneficial in many inflammatory conditions. Currently there are no specific TLR inhibitors in clinical use. To overcome this challenge, we have developed a nano-based TLR inhibitor (peptide-gold nanoparticle hybrids) that inhibits a broad spectrum of TLR responses. Through mechanistic studies, we established that specific peptide decorated-gold nanoparticles that display high cellular uptake in phagocytic immune cells modulate endosomal pH, leading to significant attenuation of signaling through multiple TLRs. Using a global transcriptomic approach, we defined the broad anti-inflammatory activity of the nanoparticle in human peripheral blood mononuclear cells. In vivo studies confirmed the beneficial immunomodulatory activity since treatment with the nanoparticle significantly reduced weight loss, improved the disease activity index, and ameliorated colonic inflammation in a murine model of intestinal inflammation. This work enhances our fundamental understanding of the role of peptide coatings on the nanoparticle surface in regulating innate immune signaling, and identifies specific peptide decorated nanoparticles that may represent a novel class of anti-inflammatory therapeutics for human inflammatory diseases.