Epithelial Uptake Research Articles

Mind the Particle Rigidity: Blooms the Bioavailability via Rapidly Crossing the Mucus Layer and Alters the Intracellular Fate of Curcumin.

Overcoming intestinal epithelial barriers to enhance bioavailability is a major challenge for oral delivery systems. Desirable nanocarriers should simultaneously exhibit rapid mucus penetration and efficient epithelial uptake; however, they two generally require contradictory structural properties. Herein, we proposed a strategy to construct multiperformance nanoparticles by modifying the rigidity of amphiphilic nanostructures originating from soy polypeptides (SPNPs), where its ability to overcome multibarriers was examined from both in vitro and in vivo, using curcumin (CUR) as a model cargo. Low-rigidity SPNPs showed higher affinity to mucin and were prone to getting stuck in the mucus layer. When they reached epithelial cells, they tended to be endocytosed through the clathrin and macropinocytosis pathways and further transferred to lysosomes, showing severe degradation and lower transport of CUR. Increased particle rigidity generally improved the absorption of CUR, with medium-rigidity SPNPs bloomed maximum plasma concentration of CUR by 80.62-fold and showed the highest oral bioavailability. Results from monocultured and cocultured cell models demonstrated that medium-rigidity SPNPs were least influenced by the mucus layer and changes in rigidity significantly influenced the endocytosis and intracellular fate of SPNPs. Those with higher rigidity preferred to be endocytosed via a caveolae-mediated pathway and trafficked to the ER and Golgi, facilitating their whole transcytosis, and avoiding intracellular metabolism. Moreover, rigidity modulation efficiently induces the reversible opening of intercellular tight junctions, which synergistically improves the transport of CUR into blood circulation. This study suggested that rigidity regulation on food originated amphiphilic peptides could overcome multiple physiological barriers, showing great potential as natural building block toward oral delivery.

Dietary limonene promotes gastrointestinal barrier function via upregulating tight/adherens junction proteins through cannabinoid receptor type-1 antagonistic mechanism and alters cellular metabolism in intestinal epithelial cells.

Limonene, a dietary monocyclic monoterpene commonly found in citrus fruits and various aromatic plants, has garnered increasing interest as a gastrointestinal protectant. This study aimed to assess the effects of limonene on intestinal epithelial barrier function and investigate the involvement of cannabinoid receptor type-1 (CB1R) in vitro. Additionally, the study focused on examining the metabolomic changes induced by limonene in the intestinal epithelial cells (Caco-2). Initial analysis of transepithelial electrical resistance (TEER) revealed that both l-limonene and d-limonene, isomers of limonene, led to a dose- and time-dependent increase in TEER in normal cells and those inflamed by pro-inflammatory cytokines mixture (CytoMix). Furthermore, both types of limonene reduced CytoMix-induced paracellular permeability, as demonstrated by a decrease in Lucifer yellow flux. Moreover, d-limonene and l-limonene treatment increased the expression of tight junction molecules (TJs) such as occludin, claudin-1, and ZO-1, at both the transcriptional and translational levels. d-Limonene upregulates E-cadherin, a molecule involved in adherens junctions (AJs). Mechanistic investigations demonstrated that d-limonene and l-limonene treatment significantly inhibited CB1R at the protein, while the mRNA level remained unchanged. Notably, the inhibitory effect of d-limonene on CB1R was remarkably similar to that of pharmacological CB1R antagonists, such as rimonabant and ORG27569. d-limonene also alters Caco-2 cell metabolites. A substantial reduction in β-glucose and 2-succinamate was detected, suggesting limonene may impact intestinal epithelial cells' glucose uptake and glutamate metabolism. These findings suggest that d-limonene's CB1R antagonistic property could effectively aid in the recovery of intestinal barrier damage, marking it a promising gastrointestinal protectant.

Biopharmaceutical profiling of anti-infective sanggenons from Morus alba root bark for inhalation administration

Mulberry Diels-Alder-type adducts (MDAAs), isolated from Morus alba root bark, exhibit dual activity against viral and bacterial pathogens but show sobering efficacy following oral administration. Inhalation administration may overcome issues with oral bioavailability and improve efficacy for the treatment of respiratory infections. To assess the suitability of MDAAs for inhalation administration, physicochemical (e.g. pH, pKa, logP, pH-dependent solubility) and biopharmaceutical (epithelial cytotoxicity, permeability, and uptake) properties of two bioactive MDAA stereoisomers sanggenon C (SGC) and sanggenon D (SGD) were evaluated as isolated natural compounds and within parent extracts (MA21, MA60). Despite their structural similarity, SGD exhibited a 10-fold higher solubility than SGC across pH 1.2–7.4, with slight increases at neutral pH. Both compounds were more soluble in isolated form than in the parent extracts. The more lipophilic SGC was found to be more cytotoxic when compared to SGD, indicating a better cellular penetration, which was confirmed by uptake studies. Nonetheless, SGC and SGD exhibited no measurable permeability across intact Calu-3 monolayers, highlighting their potential for increased lung retention and improved local anti-infective activity following inhalation administration. Results suggest that SGC and SGD in isolated form, rather than as extracts, are promising candidates for pulmonary drug delivery to treat lung infections.

Nonspecific lipid-transfer proteins trigger TLR2 and NOD2 signaling and undergo ligand-dependent endocytosis in epithelial cells

BackgroundAllergens can cross the epithelial barrier to enter the body but how this cellular passage affects protein structures and the downstream interactions with the immune system are still open questions. ObjectiveWe show the molecular details and the effects of three non-specific lipid transfer proteins (nsLTPs; Mal d 3, Cor a 8 and Pru p 3) upon epithelial cell uptake and transport. MethodsWe used fluorescent imaging, flow cytometry, proteomic and lipidomic screenings to identify the mechanism involved in nsLTP cellular uptake and signaling on selected epithelial and transgenic cell lines. ResultsNsLTPs are transported across the epithelium without affecting cell membrane stability or viability and allergen uptake was largely impaired by inhibition of clathrin-mediated endocytosis (CME). Analysis of the lipidome associated with nsLTPs showed a wide variety of lipid ligands predicted to bind inside the allergen hydrophobic cavity. Importantly, the internalization of nsLTPs was contingent upon these ligands in the protein complex.nsLTPs were found to initiate cellular signaling via TLR2 but not the CD1d receptor, despite neither being essential for nsLTP endocytosis. We also provide evidence that the three allergens induced intracellular stress signaling through activation of the NOD2 pathway. ConclusionsOur work consolidates the current model on nsLTP-epithelial cell interplay and adds molecular details about cell transport and signaling. Additionally, we have developed a versatile toolbox to extend these investigations to other allergens and cell types.

Epithelial uptake leads to fungal killing in vivo and is aberrant in COPD-derived epithelial cells

Epithelial uptake leads to fungal killing in vivo and is aberrant in COPD-derived epithelial cells

Transport of glycinin, the major soybean allergen, across intestinal epithelial IPEC-J2 cell monolayers.

Soybean allergen entering the body is the initial step to trigger intestinal allergic response. However, it remains unclear how glycinin, the major soybean allergen, is transported through the intestinal mucosal barrier. The objective of this study was to elucidate the pathway and mechanism of glycinin hydrolysatetransport through the intestinal epithelial barrier using IPEC-J2 cell model. Purified glycinin was digested by in vitro static digestion model. The pathway and mechanism of glycinin hydrolysates transport through intestinal epithelial cells were investigated by cellular transcytosis assay, cellular uptake assay, immunoelectron microscopy and endocytosis inhibition assay. The glycinin hydrolysates were transported across IPEC-J2 cell monolayers in a time/dose-dependent manner following the Michaelis equation. Immunoelectron microscopy showed a number of glycinin hydrolysates appeared in the cytoplasm, but no glycinin hydrolysates were observed in the intercellular space of IPEC-J2 cells. The inhibitors, colchicine, chlorpromazine and methyl-β-cyclodextrin,significantly inhibited the cellular uptake of glycinin hydrolysates. The glycinin hydrolysates crossed IPEC-J2 cell monolayers through the transcellular pathway. Both clathrin- and caveolae-dependent endocytosis were involved in the epithelial uptake of the hydrolysates. These findings provided potential targets for the prevention and treatment of soybean allergy.

Combination of Physicochemical Tropism and Affinity Moiety Targeting of Lipid Nanoparticles Enhances Organ Targeting.

Two camps have emerged for targeting nanoparticles to specific organs and cell types: affinity moiety targeting and physicochemical tropism. Here we directly compare and combine both using intravenous (IV) lipid nanoparticles (LNPs) designed to target the lungs. We utilized PECAM antibodies as affinity moieties and cationic lipids for physicochemical tropism. These methods yield nearly identical lung uptake, but aPECAM LNPs show higher endothelial specificity. LNPs combining these targeting methods had >2-fold higher lung uptake than either method alone and markedly enhanced epithelial uptake. To determine if lung uptake is because the lungs are the first organ downstream of IV injection, we compared IV vs intra-arterial (IA) injection into the carotid artery, finding that IA combined-targeting LNPs achieve 35% of the injected dose per gram (%ID/g) in the first-pass organ, the brain, among the highest reported. Thus, combining the affinity moiety and physicochemical strategies provides benefits that neither targeting method achieves alone.

Probing milk extracellular vesicles for intestinal delivery of RNA therapies

BackgroundOral delivery remains unattainable for nucleic acid therapies. Many nanoparticle-based drug delivery systems have been investigated for this, but most suffer from poor gut stability, poor mucus diffusion and/or inefficient epithelial uptake. Extracellular vesicles from bovine milk (mEVs) possess desirable characteristics for oral delivery of nucleic acid therapies since they both survive digestion and traverse the intestinal mucosa.ResultsUsing novel tools, we comprehensively examine the intestinal delivery of mEVs, probing whether they could be used as, or inform the design of, nanoparticles for oral nucleic acid therapies. We show that mEVs efficiently translocate across the Caco-2 intestinal model, which is not compromised by treatment with simulated intestinal fluids. For the first time, we also demonstrate transport of mEVs in novel 3D ‘apical-out’ and monolayer-based human intestinal epithelial organoids (IEOs). Importantly, mEVs loaded with small interfering RNA (siRNA) induced (glyceraldehyde 3-phosphate dehydrogenase, GAPDH) gene silencing in macrophages. Using inflammatory bowel disease (IBD) as an example application, we show that administration of anti-tumour necrosis factor alpha (TNFα) siRNA-loaded mEVs reduced inflammation in a IBD rat model.ConclusionsTogether, this work demonstrates that mEVs could either act as natural and safe systems for oral delivery or nucleic acid therapies, or inform the design of synthetic systems for such application.Graphical

Lipid Corona Formation on Micro- and Nanoplastic Particles Modulates Uptake and Toxicity in A549 Cells.

Plastic waste is a global issue leaving no continents unaffected. In the environment, ultraviolet radiation and shear forces in water and land contribute to generating micro- and nanoplastic particles (MNPP), which organisms can easily take up. Plastic particles enter the human food chain, and the accumulation of particles within the human body is expected. Crossing epithelial barriers and cellular uptake of MNPP involves the interaction of plastic particles with lipids. To this end, we generated unilamellar vesicles from POPC (1-palmitoyl-2-oleoyl-glycero-3-phosphocholine) and POPS (1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine) and incubated them with pristine, carboxylated, or aminated polystyrene spheres (about 1 µm in diameter) to generate lipid coronas around the particles. Lipid coronas enhanced the average particle sizes and partially changed the MNPP zeta potential and polydispersity. In addition, lipid coronas led to significantly enhanced uptake of MNPP particles but not their cytotoxicity, as determined by flow cytometry. Finally, adding proteins to lipid corona nanoparticles further modified MNPP uptake by reducing the uptake kinetics, especially in pristine and carboxylated plastic samples. In conclusion, our study demonstrates for the first time the impact of different types of lipids on differently charged MNPP particles and the biological consequences of such modifications to better understand the potential hazards of plastic exposure.

Engineered lipid liquid crystalline nanoparticles as an inhaled nanoplatform for mucus penetration enhancement.

Nanocarrier-assisted pulmonary drug delivery system has been widely employed for lung local disease treatment due to its enhanced drug lesion accumulation and reduced systematical side effects. However, the mucus barriers covered on the epithelia of trachea and bronchial tree construct a dense barrier for inhaled nanocarrier transport, which compromises the therapeutical effects. In this study, a lipid liquid crystalline nanoparticle NLP@Z with surface zwitterion material hexadecyl betaine (HB) modification and N-acetylcysteine (NAC) encapsulation was presented to exert the combination strategy of mucus-inert surface and mucus degradation. The HB modification endowed NLP@Z mucus-inert surface to inhibit the interaction between NLP@Z and mucins, and the encapsulated NAC could effectively degrade the mucins and further decrease the mucus viscosity. This combination strategy was proved to significantly promote the mucus penetration performance and enhance epithelial cell uptake. In addition, the proposed NLP@Z was equipped with desired nebulization property, which could be served as a potential pulmonary delivery nanoplatform. In summary, the proposed NLP@Z highlights the employment of the combination strategy for mucus penetration enhancement in pulmonary delivery, which may become a versatile platform for lung disease therapy.

Uncovering the gastrointestinal passage, intestinal epithelial cellular uptake, and AGO2 loading of milk miRNAs in neonates using xenomiRs as tracers

BackgroundHuman breast milk has a high microRNA (miRNA) content. It remains unknown whether and how milk miRNAs might affect intestinal gene regulation and homeostasis of the developing microbiome after initiating enteral nutrition. However, this requires that relevant milk miRNA amounts survive the gastrointestinal (GI) passage, are taken up by cells, and become available to the RNA interference machinery. It seems important to dissect the fate of these miRNAs after oral ingestion and GI passage. ObjectivesOur goal was to analyze the potential transmissibility of milk miRNAs via the gastrointestinal system in neonate humans and a porcine model in vivo to contribute to the discussion of whether milk miRNAs could influence gene regulation in neonates and thus might vertically transmit developmental relevant signals. MethodsWe performed cross-species profiling of miRNAs via deep sequencing and utilized dietary xenobiotic taxon-specific milk miRNA (xenomiRs) as tracers in human and porcine neonates, followed by functional studies in primary human fetal intestinal epithelial cells using adenovirus-type 5-mediated miRNA gene transfer. ResultsMammals share many milk miRNAs yet exhibit taxon-specific miRNA fingerprints. We traced bovine-specific miRNAs from formula nutrition in human preterm stool and 9 d after the onset of enteral feeding in intestinal cells (ICs) of preterm piglets. Thereafter, several xenomiRs accumulated in the ICs. Moreover, a few hours after introducing enteral feeding in preterm piglets with supplemented reporter miRNAs (cel-miR-39-5p/-3p), we observed their enrichment in blood serum and in argonaute RISC catalytic component 2 (AGO2)-immunocomplexes from intestinal biopsies. ConclusionsMilk-derived miRNAs survived GI passage in human and porcine neonates. Bovine-specific miRNAs accumulated in ICs of preterm piglets after enteral feeding with bovine colostrum/formula. In piglets, colostrum supplementation with cel-miR-39-5p/-3p resulted in increased blood concentrations of cel-miR-39-3p and argonaute RISC catalytic component 2 (AGO2) loading in ICs. This suggests the possibility of vertical transmission of miRNA signaling from milk through the neonatal digestive tract.

In situ rearranged multifunctional lipid nanoparticles via synergistic potentiation for oral insulin delivery

Oral administration of therapeutic peptides/proteins (TPPs) is confronted with multiple gastrointestinal (GI) barriers such as mucus and intestinal epithelium, and the first-pass metabolism in the liver is also responsible for low bioavailability. In situ rearranged multifunctional lipid nanoparticles (LNs) were developed to overcome these obstacles via synergistic potentiation for oral insulin delivery. After the reverse micelles of insulin (RMI) containing functional components were gavaged, LNs formed in situ under the hydration effect of GI fluid. The nearly electroneutral surface generated by the rearrangement of sodium deoxycholate (SDC) and chitosan (CS) on the reverse micelle core facilitated LNs (RMI@SDC@SB12-CS) to overcome mucus barrier and the sulfobetaine 12 (SB12) modification further promoted epithelial uptake of LNs. Subsequently, chylomicron-like particles formed by the lipid core in the intestinal epithelium were easily transported to the lymphatic circulation and then into the systemic circulation, thus avoiding hepatic first-pass metabolism. Eventually, RMI@SDC@SB12-CS achieved a high pharmacological bioavailability of 13.7% in diabetic rats. In conclusion, this study provides a versatile platform for enhanced oral insulin delivery.

Inhibition of Transglutaminase 2 as a Therapeutic Strategy in Celiac Disease-In Vitro Studies in Intestinal Cells and Duodenal Biopsies.

Enzymatic modification of gliadin peptides by human transglutaminase 2 (TG2) is a key mechanism in the pathogenesis of celiac disease (CD) and represents a potential therapeutic target. Recently, we have identified the small oxidative molecule PX-12 as an effective inhibitor of TG2 in vitro. In this study, we further investigated the effect of PX-12 and the established active-site directed inhibitor ERW1041 on TG2 activity and epithelial transport of gliadin peptides. We analyzed TG2 activity using immobilized TG2, Caco-2 cell lysates, confluent Caco-2 cell monolayers and duodenal biopsies from CD patients. TG2-mediated cross-linking of pepsin-/trypsin-digested gliadin (PTG) and 5BP (5-biotinamidopentylamine) was quantified by colorimetry, fluorometry and confocal microscopy. Cell viability was tested with a resazurin-based fluorometric assay. Epithelial transport of promofluor-conjugated gliadin peptides P31-43 and P56-88 was analyzed by fluorometry and confocal microscopy. PX-12 reduced TG2-mediated cross-linking of PTG and was significantly more effective than ERW1041 (10 µM, 15 ± 3 vs. 48 ± 8%, p < 0.001). In addition, PX-12 inhibited TG2 in cell lysates obtained from Caco-2 cells more than ERW1041 (10 µM; 12 ± 7% vs. 45 ± 19%, p < 0.05). Both substances inhibited TG2 comparably in the intestinal lamina propria of duodenal biopsies (100 µM, 25 ± 13% vs. 22 ± 11%). However, PX-12 did not inhibit TG2 in confluent Caco-2 cells, whereas ERW1041 showed a dose-dependent effect. Similarly, epithelial transport of P56-88 was inhibited by ERW1041, but not by PX-12. Cell viability was not negatively affected by either substance at concentrations up to 100 µM. PX-12 did not reduce TG2 activity or gliadin peptide transport in confluent Caco-2 cells. This could be caused by rapid inactivation or degradation of the substance in the Caco-2 cell culture. Still, our in vitro data underline the potential of the oxidative inhibition of TG2. The fact that the TG2-specific inhibitor ERW1041 reduced the epithelial uptake of P56-88 in Caco-2 cells further strengthens the therapeutic potential of TG2 inhibitors in CD.

Tailor-Made Protein Corona Formation on Polystyrene Microparticles and its Effect on Epithelial Cell Uptake.

Microplastic particles are pollutants in the environment with a potential impact on ecology and human health. As soon as microplastic particles get in contact with complex (biological) environments, they will be covered by an eco- and/or protein corona. In this contribution, protein corona formation was conducted under defined laboratory conditions on polystyrene (PS) microparticles to investigate the influence on surface properties, protein corona evolution, particle-cell interactions, and uptake in two murine epithelial cells. To direct protein corona formation, PS particles were preincubated with five model proteins, namely, bovine serum albumin (BSA), myoglobin, β-lactoglobulin, lysozyme, and fibrinogen. Subsequently, the single-protein-coated particles were incubated in a cell culture medium containing a cocktail of serum proteins to analyze changes in the protein corona profile as well as in the binding kinetics of the model proteins. Therein, we could show that the precoating step has a critical impact on the final composition of the protein corona. Yet, since proteins building the primary corona were still detectable after additional incubations in a protein-containing medium, backtracking of the particle's history is possible. Interestingly, whereas the precoating history significantly disturbs particle-cell interactions (PCIs), the cellular response (i.e., metabolic activity, MTT assay) stays unaffected. Of note, lysozyme precoating revealed one of the highest rates in PCI for both epithelial cell lines. Taken together, we could show that particle history has a significant impact on protein corona formation and subsequently on the interaction of particles with murine intestinal epithelial-like cells. However, as this study was limited to one cell type, further work is needed to assess if these observations can be generalized to other cell types.

Lowering effect of combined sweet potato and onion intake on plasma quercetin concentration and underlying mechanism involving intestinal β-glucosidase activity.

A combined intake of cooked sweet potato and fried onion in humans was found to suppress the increase of plasma quercetin metabolite concentration. Experiments using rat β-glucosidase indicated that excess carbohydrate digestion products, especially glucose-containing saccharides, interfere with the deglycosylation of quercetin glucosides during intestinal epithelial uptake. Combined meals of sweet potato and onion may lower the bioavailability of onion quercetin glucosides.

Transcriptional regulation of milk fat synthesis in dairy cattle

With the rapid development of China's economy and dairy industry, the people’s requirement for milk quality is increasing. Milk fat is a crucial indicator of milk quality. Therefore, exploring the regulatory mechanisms of milk fat synthesis is important. Depending on chain length, milk fatty acids are produced through two mechanisms: de novo synthesis in mammary epithelial cells and uptake from circulating blood. Milk fat synthesis involves many enzymes, proteins and regulatory factors and is a complex and dynamic process. In this paper, recent progress in the transcriptional regulation of milk fat synthesis is reviewed with a focus on the de novo synthesis of fatty acids, the uptake and transport of preformed fatty acids, fatty acid desaturation, triglyceride formation and lipid droplet secretion. In particular, the recently discovered regulatory roles of noncoding RNA are emphasized. Our paper will provide a reference for future research on milk fat derived from dairy cows.

“Two-birds-one-stone” colon-targeted nanomedicine treats ulcerative colitis via remodeling immune microenvironment and anti-fibrosis

Dysregulated mucosal immune responses and colonic fibrosis impose two formidable challenges for ulcerative colitis treatment. It indicates that monotherapy could not sufficiently deal with this complicated disease and combination therapy may provide a potential solution. A chitosan-modified poly(lactic-co-glycolic acid) nanoparticle (CS-PLGA NP) system was developed for co-delivering patchouli alcohol and simvastatin to the inflamed colonic epithelium to alleviate the symptoms of ulcerative colitis via remodeling immune microenvironment and anti-fibrosis, a so-called “two-birds-one-stone” nanotherapeutic strategy. The bioadhesive nanomedicine enhanced the intestinal epithelial cell uptake efficiency and improved the drug stability in the gastrointestinal tract. The nanomedicine effectively regulated the Akt/MAPK/NF-κB pathway and reshaped the immune microenvironment through repolarizing M2Φ, promoting regulatory T cells and G-MDSC, suppressing neutrophil and inflammatory monocyte infiltration, as well as inhibiting dendritic cell maturation. Additionally, the nanomedicine alleviated colonic fibrosis. Our work elucidates that the colon-targeted codelivery for combination therapy is promising for ulcerative colitis treatment and to address the unmet medical need.Graphical

Barriers to the Intestinal Absorption of Four Insulin-Loaded Arginine-Rich Nanoparticles in Human and Rat.

Peptide drugs and biologics provide opportunities for treatments of many diseases. However, due to their poor stability and permeability in the gastrointestinal tract, the oral bioavailability of peptide drugs is negligible. Nanoparticle formulations have been proposed to circumvent these hurdles, but systemic exposure of orally administered peptide drugs has remained elusive. In this study, we investigated the absorption mechanisms of four insulin-loaded arginine-rich nanoparticles displaying differing composition and surface characteristics, developed within the pan-European consortium TRANS-INT. The transport mechanisms and major barriers to nanoparticle permeability were investigated in freshly isolated human jejunal tissue. Cytokine release profiles and standard toxicity markers indicated that the nanoparticles were nontoxic. Three out of four nanoparticles displayed pronounced binding to the mucus layer and did not reach the epithelium. One nanoparticle composed of a mucus inert shell and cell-penetrating octarginine (ENCP), showed significant uptake by the intestinal epithelium corresponding to 28 ± 9% of the administered nanoparticle dose, as determined by super-resolution microscopy. Only a small fraction of nanoparticles taken up by epithelia went on to be transcytosed via a dynamin-dependent process. In situ studies in intact rat jejunal loops confirmed the results from human tissue regarding mucus binding, epithelial uptake, and negligible insulin bioavailability. In conclusion, while none of the four arginine-rich nanoparticles supported systemic insulin delivery, ENCP displayed a consistently high uptake along the intestinal villi. It is proposed that ENCP should be further investigated for local delivery of therapeutics to the intestinal mucosa.

Co-delivery of celastrol and lutein with pH sensitive nano micelles for treating acute kidney injury

To treat acute kidney injury with high efficiency and low toxicity, a novel nanoplatform was developed to remove excess reactive oxygen species (ROS). Lutein (LU) and celastrol (Cel) were loaded into low molecular weight chitosan (CS) to prepare Cel@LU-CA-CS nanomicelles. Renal tubular epithelial (HK−2) cell uptake experiments showed that the drugs could be internalized in renal tubular via the megalin receptor. In this study, the amide bond formed by the reaction of citraconic anhydride (CA) with an amino group of CS could be destroyed under acidic conditions.Therefore, the drugs were released in HK-2 cells due to the acidic environment of the lysosome. In vitro studies showed that the nanomicelles could reduce toxicity in non-target organs and enhance therapeutic efficacy in acute kidney injury (AKI). In addition, Cel@LU-CA-CS micelles had alleviated kidney oxidative stress disorder and stabilized the mitochondrial membrane potential quickly. Next, in vivo studies proved that Cel@LU-CA-CS micelles could inhibit the activation of the NF-κB p65 and p38 MAPK inflammatory signaling pathways. Therefore, the micelles further reduced the overexpression of related inflammatory factors. In conclusion, Cel@LU-CA-CS nanomicelles could treat AKI with high efficiency and low toxicity, and inhibit renal fibrosis.

Effects of subject-variability on nasally inhaled drug deposition, uptake, and clearance

Accurate and realistic predictions of the fate of nasally inhaled generic drugs provide new physical insight which can be of great importance to toxicologists, drug developers and federal regulators alike. To understand the dynamics of mucociliary clearance (MCC) and subsequent absorption of the dissolved drug by the nasal epithelium, it becomes necessary to model the air-particle-mucus dynamics accurately. The MCC process, including particle dissolution, transport and absorption for a 3-D representative nasal cavity, were established by Chari et al. (2021). In this study, the effects of inter-subject variability of three representative nasal cavities (subjects A, B, C) on deposition and subsequent uptake of the dissolved drug in the nasal epithelium are analyzed for three generic drugs: Mometasone furoate (MF), Flunisolide (FN), and Ribavirin (RB). The computational fluid-particle dynamics (CF-PD) results indicate that smaller sized particles (3 μm) deposit more in the ciliated portion of the nasal cavity where the columnar cells responsible for uptake are present. In contrast, larger particles (10 μm) tend to deposit in the unciliated anterior third of the nose. The epithelial uptake in case of subject A was considerably higher than that in subjects B and C because of the unique anatomical characteristics of subject A. Also, FN and RB were found to have a higher rate of uptake compared to MF due to their considerably higher partition coefficient. As a visualization tool, concentration contours are used to explain regional trends in cumulative drug uptake for all three cases.