Tissue Retention Research Articles

A supramolecular gel with unique rheological properties for treating corneal virus infection

Herpes simplex keratitis (HSK) caused by herpes simplex virus-1 infection of the cornea has taken a significant toll on the visual health of people worldwide. Anti-viral hydrogels are preferred in the treatment of HSK due to enhanced topical drug retention and reduced side effects, however, current polymer-based gelling systems usually generate clumpy or uneven gel layers on ocular surface, and are easily cleared by eyelid blinking. This study proposes a supramolecular gel co-assembled by all-small-molecule building blocks including ganciclovir and 2′-deoxyguanosine in the presence of potassium ions. The developed gel performs fascinating rheological and texture properties including high viscoelastic, good spread ability, and deformation recovery behavior, enabling the formation of a uniform and thin gel layer on ocular surface to resist the clearance by eyelid blinking and tear washing. The gel shows similar ocular convenience, but much longer drug retention in ocular tissues and higher therapeutic efficacy compared to the clinical ganciclovir gel on the primary and recurrent mouse HSK models, rabbit HSK models, and also efficiently inhibited the HSV-1 replication in ex vivo human corneal tissues. The results suggest that this all-small-molecule supramolecular gel could be a promising drug formulation for treating HSK. Data and materials availabilityThe main data supporting the results in this study are available within the paper and its Supplementary Information. The associated raw data and analyzed datasets are too large to be readily shared publicly, but they are available from the corresponding author on reasonable request.

Oral ω-3 PUFA supplementation modulates inflammation in adipose tissue depots in morbidly obese women: A randomized trial

ObjectivesObesity is characterized by local and systemic low-grade inflammatory responses. Adipose tissue macrophages (ATM) play decisive roles in inflammation, insulin signaling, and various metabolic dysfunctions. Diets enriched with ω-3 polyunsaturated fatty acids (PUFAs) have been shown to improve health and mitigate pathologic conditions. However, the effects of ω-3 PUFA on adipose tissue inflammation, ATM number, and phenotype are poorly defined in human obesity. The aim of this study was to examine differences in expression of metabolic-inflammatory markers in omental, mesenteric, and subcutaneous fat depots of obese women supplemented with ω-3 PUFAs for 4 wk compared with a low-calorie diet before bariatric surgery. MethodsIn a randomized controlled trial, inflammatory markers in the abdominal adipose tissue and the systemic response in obese women were studied. Patients were treated with a 2-wk low-calorie diet (LCD) or a 4-wk ω-3 PUFA-enriched diet (920 mg eicosapentaenoic acid, 760 mg docosahexaenoic acid daily) before laparoscopic bypass surgery. Omental, mesenteric, and subcutaneous adipose tissue biopsies were collected during surgery and analyzed for quantity and phenotype of ATMs, and profiled for adipokines, cytokines, and signal transduction molecules. ResultsThe chronic inflammatory state characterized by ATM markers was mostly improved by ω-3 PUFAs in visceral adipose tissue. We observed a decreased expression of CD45, CCL2, and CD68, indicating a lower inflammatory state. In patients with type 2 diabetes, ω-3 PUFAs lowered the expression of Netrin-1. ConclusionsCompared with an LCD, a diet enriched with ω-3 PUFAs influences the inflammatory state in different adipose tissue depots, by affecting markers of adipose tissue inflammation, macrophage phenotype, and retention. However, this was not reflected in clinical parameters such as insulin resistance and inflammatory cytokines. Subcutaneous adipose tissue and visceral adipose tissue have different responses to an LCD or a ω-3 PUFA-enriched diet. The presence of diabetes modifies the expression of inflammatory markers.

Abstract 6339: BCA101, a novel tumor-targeted bifunctional fusion antibody simultaneously inhibiting EGFR and TGF-β signaling with potential for durable tumor growth inhibition

Abstract Introduction: The suboptimal clinical efficacy EGFR-targeting therapeutics is attributed to both tumor intrinsic and tumor microenvironment (TME) derived acquired (extrinsic) resistance mechanisms. Intrinsic factors include activation of other receptor tyrosine kinases and key extrinsic resistance mechanism include the enhanced secretion of immunosuppressive factors such as IL-10 and TGF-β1. Here, we describe a first-in-class bifunctional monoclonal antibody fusion designed to simultaneously target EGFR and sequester TGF-β in the TME. Experimental Procedures: Functional activity of BCA101 was evaluated in multiple in vitro assays such as ELISA, inhibition of proliferation, antibody-dependent cellular toxicity, SMAD-reporter assay. Neutralization of TGF-β by BCA101 was demonstrated by epithelial-to-mesenchymal transition and tumor cell/immune cell co-culture assays. BCA101 tumor targeting was evaluated in a whole animal imaging study and efficacy studies were performed in nude xenograft models while combination studies with immune checkpoint inhibitors were performed in B16-EGFR syngeneic models. Results: BCA101 is an anti-EGFR IgG1 monoclonal antibody linked to an extracellular domain of human TGF-βRII. The TGF-β “trap” fused to light chain in BCA101 did not sterically interfere with its ability to bind EGFR, inhibit cell proliferation, or mediate antibody-dependent cellular cytotoxicity in vitro. BCA101 increased production of proinflammatory cytokines and key markers associated with T and NK cell activation, while suppressing VEGF secretion. Additionally, BCA101 inhibited differentiation of naïve CD4+ T cells to inducible T-regulatory (iTreg) cells when compared to cetuximab. In vivo, biodistribution studies showed that BCA101 localized to tumor tissues in xenograft mouse models, with comparable kinetics as cetuximab. TGF-β in tumors was neutralized to about 90% in animals dosed with 10 mg/kg of BCA101 compared to 54% in animals dosed with equimolar TGF-βRII-Fc. BCA101 had longer tumor tissue retention compared to cetuximab, further confirming improved tumor localization. In patient-derived xenograft mouse models of head and neck squamous cell carcinoma, BCA101 showed durable response post dose cessation as compared to cetuximab. In FaDu xenografts, BCA101 displayed early and durable response to cetuximab/cetuximab plus TGF-βRII-Fc combination. The combination of BCA101 and anti-PD1 antibody improved tumor inhibition in both B16-hEGFR expressing syngeneic mouse and in humanized HuNOG-EXL mice bearing human PC-3 xenograft models. Conclusion: These results support clinical development of BCA101, either as a monotherapy or in combination with immune checkpoint therapy. Citation Format: Srinivas Reddy Boreddy, Reshmi Nair, Prashant Kumar Pandey, Anshu Kuriakose, Arindam Banerjee, Chaitali Dey, Madhukara A R, Bhadravathi Marigowda Shivakumar, Hanumant Kulkarni, Milind Sagar, Prashantha Kumar M. V, Shiv Ram Krishn, Jaya Bhatnagar, Moni Abhram Kuriakose, Ram Bhupal Reddy, Amritha Suresh, Praveen Reddy Moole, Usha Bughani, Seng-Lai Tan, Pradip Nair, Rachel Salazar. BCA101, a novel tumor-targeted bifunctional fusion antibody simultaneously inhibiting EGFR and TGF-β signaling with potential for durable tumor growth inhibition. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6339.

Abstract 3464: Dynamics of resident memory (Trm) cell responses between skin and draining lymph nodes during primary and recall responses to melanoma

Abstract Tissue resident memory (TRM) cells reside durably in tissues where they serve as a vital component of protective anti-tumor immunity. In mice, TRM cells are defined by their expression of tissue retention markers such as CD69 and CD103, and lack of egress markers such as CD62L, CCR7 and S1PR1. We previously showed that depletion of regulatory T cells induces the generation of protective CD8 Trm cells in skin and draining LNs of B16 melanoma tumor-excised mice. While tumor specific Trm cells were shown to stably reside in tissues at steady state, little is known about their migration between tissue compartments and circulation during primary and recall responses to melanoma. Using gp100-specific transgenic pmel CD8 T cells expressing a Kaede-GFP photoconvertible marker, we investigated the trafficking patterns of tumor Ag specific CD8+ T-cells that were labeled in situ by exposure to UV light in the skin. During primary tumor growth, we observed pronounced movement of antigen-experienced pmel cells through skin to tumor-draining LNs. This trafficking behavior could be inhibited by treatment with FTY720, indicating its S1PR-dependence. Such movement was no longer evident at memory timepoints. However, re-challenge with B16 cells in the dermis induced rapid pmel T cell egress to both LNs and circulation. Recallenge-mediated Trm cell skin egress was confirmed using anti-Thy1.1 monoclonal antibody to deplete circulating and lymphoid memory, while preserving skin TRM. Here we found that skin TRM proliferate and transiently increase expression of Tbet, but go on to generate a durable secondary Trm response in lymph nodes. These data highlight T cell movement between tissues during Trm programming and recall responses to cancer, and shed light on a potential mechanism for the generation TRM populations in tumor-draining lymph nodes. Moreover, our results highlight the potential for retrograde movement of Trm responses from peripheral tissue reservoirs to participate more broadly in systemic anti-tumor immunity. Citation Format: Cameron Messier, Nikhil Khatwani, Aaron Hawkes, Yuyang (Poppy) Huang, Mary Jo Turk. Dynamics of resident memory (Trm) cell responses between skin and draining lymph nodes during primary and recall responses to melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3464.

Near-infrared fluorescence imaging of hepatocellular carcinoma cells regulated by β-catenin signaling pathway.

Near-infrared fluorescence (NIRF) imaging has recently emerged as a promising tool for noninvasive cancer imaging. However, lack of tumor sensitivity and specificity restricts the application of NIRF dyes in surgical navigation. Herein, we investigated the imaging features of NIRF dye MHI-148 and indocyanine green (ICG) in live cell imaging and xenograft nude mice models. TCGA dataset analysis and immunohistochemistry were conducted to investigate the expression of OATPs or ABCGs in hepatocellular carcinoma (HCC) tissues. OATPs or ABCGs were knocked down and overexpressed in HCC cells using transient transfection by siRNA and plasmids or stable transfection by lentivirus. Further, qRT-PCR ,Western blotting and the use of agonists or inhibitors targeting β-catenin signaling pathway were applied to explore its important role in regulation of OATP2B1 and ABCG2 expression. Here we demonstrated that NIRF dye MHI-148 was biocompatible as indocyanine green (ICG) but with higher imaging intensity and preferential uptake and retention in hepatocellular carcinoma (HCC) cells and tissues. Moreover, our data indicated that membrane transporters OATP2B1 and ABCG2, which regulated by β-catenin signaling pathway, mediated tumor-specific accumulation and retention of MHI-148 in HCC cells. In addition, the treatment with β-catenin inhibitor significantly enhanced the accumulation of MHI-148 in HCC tissues and improved the efficacy of tumor imaging with MHI-148 in vivo. Our study uncovers a mechanism that links the distribution and expression of the membrane transporters OATP2B1 and ABCG2 to the tumor-specific accumulation of MHI-148, and provides evidence supporting a regulating role of the β-catenin signaling pathway in OATP2B1 and ABCG2- induced retention of MHI-148 inHCC tissues, and strategy targeting key components of MHI-148 transport machinery may be a potential approach to improve HCC imaging.

Volumetric assessment of fat graft retention over implant by MRI

**Background**: Autologous fat grafting (AFG) is an increasingly popular adjunct to post-mastectomy breast reconstruction as it can produce a natural cosmetic outcome and alleviate undesirable radiotherapy-associated consequences, with low surgical risk. However, graft retention rates are variable and unpredictable. In order to improve and understand what influences graft retention rates, accurate and consistent methods for the measurement of graft retention must be developed.**Methods**: Twenty patients who were undergoing AFG following a previous mastectomy were prospectively enrolled. Of these, six women suitable for immediate breast reconstruction (IBR) with implant underwent MRI pre- and three months post-AFG. **Results**: All patients had a net gain in volume at three months post-procedure with a mean of 123.6 ± 56.07cm^3^; however, the percentage retention ranged from 30.0 to 104.7 per cent. **Conclusions**: This study has demonstrated the feasibility of measuring AFG retention over implant using MRI, as well as confirming variable tissue retention rates. This is an important step forward for studies on improving overall graft survival.

Recent Emerging Immunological Treatments for Primary Brain Tumors: Focus on Chemokine-Targeting Immunotherapies

Primary brain tumors are a leading cause of death worldwide and are characterized by extraordinary heterogeneity and high invasiveness. Current drug and radiotherapy therapies combined with surgical approaches tend to increase the five-year survival of affected patients, however, the overall mortality rate remains high, thus constituting a clinical challenge for which the discovery of new therapeutic strategies is needed. In this field, novel immunotherapy approaches, aimed at overcoming the complex immunosuppressive microenvironment, could represent a new method of treatment for central nervous system (CNS) tumors. Chemokines especially are a well-defined group of proteins that were so named due to their chemotactic properties of binding their receptors. Chemokines regulate the recruitment and/or tissue retention of immune cells as well as the mobilization of tumor cells that have undergone epithelial-mesenchymal transition, promoting tumor growth. On this basis, this review focuses on the function and involvement of chemokines and their receptors in primary brain tumors, specifically examining chemokine-targeting immunotherapies as one of the most promising strategies in neuro-oncology.

Short-term supplementation of zinc nanoparticles in weaned piglets affects zinc bioaccumulation and carcass classification

High doses of zinc have been used as a prevention against weaned piglets' diarrhea for many years. Nevertheless, since 2022 high doses of zinc oxide have been banned in EU. Currently, there are several studies about the potential of zinc nanoparticles in lower doses which could maintain a preventive effect. Several concerns about nanoparticles' toxicity and bioaccumulation have been raised in many other fields of research. The aim of this short follow-up study is focused on the impact of zinc nanoparticles used as a prevention of diarrhea for weaned piglets, on the classification of slaughtered pigs’ carcasses and on zinc retention in muscle tissue. Seventy piglets (10 groups of 7 piglets) were fed a standard diet. The treated groups’ diets were supplemented with zinc oxide (ZnO), and phosphate-based nanoparticles: spherical- shaped type A (ZnA) and irregular-shaped: type C (ZnC), at the doses of 500, 1000 and 2000 mg Zn equivalent per kilogram of diet. The control group´s diet was not treated with zinc in any form. The feed experiment started when the piglets were 28 days old and lasted for 10 days. Experimental animals were grown to the final weight 120 ± 10 kg and slaughtered in a slaughterhouse. The pig carcasses were evaluated according to S/EUROP standards: the pigs’ weight, back fat thickness and lean meat content were monitored. Moreover, zinc concentrations in M. longissimus dorsi et thoracis were analyzed. The results have not proved significant changes in S/EUROP standard classification and zinc bioaccumulation in muscle tissue. This follow-up experiment was carried out as part of maintaining a precautionary approach to the use the nanoparticles in piglet fattening. In our study we did not confirm their effect on the assessment of carcass classification and their bioaccumulation in muscle tissue.

Ferumoxytol-Enhanced MRI in Children and Young Adults: State of the Art.

Ferumoxytol is an ultrasmall iron oxide nanoparticle that was originally approved by the FDA in 2009 for IV treatment of iron deficiency in adults with chronic kidney disease. Subsequently, its off-label use as an MRI contrast agent increased in clinical practice, particularly in pediatric patients in North America. Unlike conventional MRI contrast agents that are based on the rare earth metal gadolinium (gadolinium-based contrast agents), ferumoxytol is biodegradable and carries no potential risk of nephrogenic systemic fibrosis. At FDA-approved doses, ferumoxytol shows no long-term tissue retention in patients with intact iron metabolism. Ferumoxytol provides unique MRI properties, including long-lasting vascular retention (facilitating high-quality vascular imaging) and retention in reticuloendothelial system tissues, thereby supporting a variety of applications beyond those possible with gadolinium-based contrast agents (GBCAs). This Clinical Perspective describes clinical and early translational applications of ferumoxytol-enhanced MRI in children and young adults through off-label use in a variety of settings, including vascular, cardiac, and cancer imaging, drawing on the institutional experience of the authors. In addition, we describe current advances in pre-clinical and clinical research using ferumoxytol in cellular and molecular imaging as well as the use of ferumoxytol as a novel potential cancer therapeutic agent.

Re-evaluation of the existing health-based guidance values for copper and exposure assessment from all sources.

Copper is an essential micronutrient and also a regulated product used in organic and in conventional farming pest management. Both deficiency and excessive exposure to copper can have adverse health effects. In this Scientific Opinion, the EFSA 2021 harmonised approach for establishing health-based guidance values (HBGVs) for substances that are regulated products and also nutrients was used to resolve the divergent existing HBGVs for copper. The tightly regulated homeostasis prevents toxicity manifestation in the short term, but the development of chronic copper toxicity is dependent on copper homeostasis and its tissue retention. Evidence from Wilson disease suggests that hepatic retention is indicative of potential future and possibly sudden onset of copper toxicity under conditions of continuous intake. Hence, emphasis was placed on copper retention as an early marker of potential adverse effects. The relationships between (a) chronic copper exposure and its retention in the body, particularly the liver, and (b) hepatic copper concentrations and evidence of toxicity were examined. The Scientific Committee (SC) concludes that no retention of copper is expected to occur with intake of 5mg/day and established an Acceptable Daily Intake (ADI) of 0.07mg/kg bw. A refined dietary exposure assessment was performed, assessing contribution from dietary and non-dietary sources. Background copper levels are a significant source of copper. The contribution of copper from its use as plant protection product (PPP), food and feed additives or fertilisers is negligible. The use of copper in fertilisers or PPPs contributes to copper accumulation in soil. Infant formula and follow-on formula are important contributors to dietary exposure of copper in infants and toddlers. Contribution from non-oral sources is negligible. Dietary exposure to total copper does not exceed the HBGV in adolescents, adults, elderly and the very elderly. Neither hepatic copper retention nor adverse effects are expected to occur from the estimated copper exposure in children due to higher nutrient requirements related to growth.

Tumor polyamines as guest cues attract host-functionalized liposomes for targeting and hunting via a bio-orthogonal supramolecular strategy.

Inspired by the attractions of fruit flies to polyamines of rotten food, we developed a facile, bio-orthogonal, supramolecular homing and hunting strategy, relying on the elevated levels of polyamines in tumor as the natural guest cues to attract cucurbit [7] uril (CB[7]) functionalized liposomes to the tumor site, owing to the strong, bio-orthogonal host-guest interactions between CB[7] and polyamines. This supramolecular homing enabled a high targeting efficiency of CB[7] functionalized liposomes, and allowed better tissue penetration and retention in breast tumor. The employment of a receptor functionalized nanomedicine for direct tropism towards endogenous biomarkers as guest cues, reminiscent of natural chemotaxis but in a bio-orthogonal manner, has not been previously reported, offering new sights to the design and development of new nanoformulations that rely on bio-orthogonal interactions for chemotaxis-guided targeting.

Zwitterionic rhodamine-CPT prodrug nanoparticles with GSH/H2O2 responsiveness for cancer theranostics.

Rationale: Fluorescently traceable prodrugs, which can monitor their biodistribution in vivo and track the kinetics of drug delivery in living cells, are promising for constructing theranostic medicines. However, due to their charge and hydrophobicity, most of the fluorescently traceable prodrugs exhibit high protein binding and non-specific tissue retention affecting in vivo distribution and toxicity, with high background signals. Methods: Herein, the zwitterionic rhodamine (RhB) and camptothecin (CPT) were bridged with a disulfide bond to construct a tumorous heterogeneity-activatable prodrug (RhB-SS-CPT). The interaction of zwitterionic RhB-SS-CPT with proteins was detected by UV and fluorescence spectroscopy, and further demonstrated by molecular docking studies. Then, intracellular tracking and cytotoxicity of RhB-SS-CPT were determined in tumor and normal cells. Finally, the in vivo biodistribution, pharmacokinetics, and anticancer efficacy of RhB-SS-CPT were evaluated in a mouse animal model. Results: The tumorous heterogeneity-activatable RhB-SS-CPT prodrug can self-assemble into stable nanoparticles in water based on its amphiphilic structure. Particularly, the zwitterionic prodrug nanoparticles reduce the non-specific binding to generate a low background signal for better identification of cancerous lesions, achieve rapid internalization into cancer cells, selectively release bioactive CPT as a cytotoxic agent in response to high levels of GSH and H2O2, and exhibit high fluorescence that contributes to the visual chemotherapy modality. In addition, the RhB-SS-CPT prodrug nanoparticles show longer circulation time and better antitumor activity than free CPT in vivo. Interestingly, the zwitterionic nature allows RhB-SS-CPT to be excreted through the renal route, with fewer side effects. Conclusions: Zwitterionic features and responsive linkers are important considerations for constructing potent prodrugs, which provide some useful insights to design the next-generation of theranostic prodrugs for cancer.

Effects of Two Soluble ACE2-Fc Variants on Blood Pressure and Albuminuria in Hypertensive Mice: Research Letter.

Angiotensin-converting enzyme 2 (ACE2) hydrolyzes angiotensin (Ang) II to Ang-(1-7), promoting vasodilatation, and inhibiting oxidative stress and inflammation. Plasma membrane ACE2 is the receptor for all known SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) viral variants. In COVID-19 infection, soluble ACE2 variants may act as decoys to bind and neutralize the coronavirus, reducing its tissue infectivity. Furthermore, soluble ACE2 variants have been proposed as potential therapeutics for kidney disease and hypertensive disorders. Soluble ACE2 variants conjugated to human Fc domains and selected for high-potency viral SARS-CoV-2 neutralization were prepared and evaluated for ACE2 activity in vitro. Lead candidates were then tested for systemic ACE2 activity, stability, and effects on blood pressure and albuminuria in mice with Ang II-induced hypertension. ACE2 activity of 10 soluble ACE2 variants was first assessed in cell-free conditions using a fluorogenic substrate, or by Ang II hydrolysis to Ang-(1-7). Hypertension was induced in male or female mice by implantation of osmotic minipumps containing Ang II. Two lead ACE2 variants were injected intravenously (i.v.) into hypertensive mice, followed by measurements of blood pressure (tail-cuff plethysmography), albuminuria, and tissue ACE2 activity and protein (immunoblots). Soluble ACE2-Fc variants demonstrated significant ACE2 enzymatic activity, with kinetics comparable with human recombinant ACE2. In hypertensive mice, single dose i.v. injection of ACE2-Fc variant K (10 mg/kg) significantly decreased systolic blood pressure at 24 hours, with partial lowering sustained to 48 hours, and tendency to reduce albuminuria at 72 hours. By contrast, ACE2-Fc variant I had no effect on blood pressure or albuminuria in hypertensive mice; ACE2-Fc variant K was detected by immunoblotting in plasma, kidney, heart, lung, liver, and spleen lysates 72 hours after injection, associated with significantly increased ACE2 activity in all tissues except kidney and spleen. Angiotensin-converting enzyme 2-Fc variant I had no effect on plasma ACE2 activity. Soluble ACE2-Fc variant K reduces blood pressure and tends to lower albuminuria in hypertensive mice. Furthermore, soluble ACE2-Fc variant K has prolonged tissue retention, associated with increased tissue ACE2 activity. The results support further studies directed at the therapeutic potential of soluble ACE2-Fc variant K for cardiovascular and kidney protection.

The Effects of Antioxidant Nutraceuticals on Cellular Sulfur Metabolism and Signaling.

Significance: Nutraceuticals are ingested for health benefits, in addition to their general nutritional value. These dietary supplements have become increasingly popular since the late 20th century and they are a rapidly expanding global industry approaching a half-trillion U.S. dollars annually. Many nutraceuticals are promulgated as potent antioxidants. Recent Advances: Experimental support for the efficacy of nutraceuticals has lagged behind anecdotal exuberance. However, accumulating epidemiological evidence and recent, well-controlled clinical trials are beginning to support earlier animal and in vitro studies. Although still somewhat limited, encouraging results have been suggested in essentially all organ systems and against a wide range of pathophysiological conditions. Critical Issues: Health benefits of "antioxidant" nutraceuticals are largely attributed to their ability to scavenge oxidants. This has been criticized based on several factors, including limited bioavailability, short tissue retention time, and the preponderance of endogenous antioxidants. Recent attention has turned to nutraceutical activation of downstream antioxidant systems, especially the Keap1/Nrf2 (Kelch like ECH associated protein 1/nuclear factor erythroid 2-related factor 2) axis. The question now becomes, how do nutraceuticals activate this axis? Future Directions: Reactive sulfur species (RSS), including hydrogen sulfide (H2S) and its metabolites, are potent activators of the Keap1/Nrf2 axis and avid scavengers of reactive oxygen species. Evidence is beginning to accumulate that a variety of nutraceuticals increase cellular RSS by directly providing RSS in the diet, or through a number of catalytic mechanisms that increase endogenous RSS production. We propose that nutraceutical-specific targeting of RSS metabolism will lead to the design and development of even more efficacious antioxidant therapeutic strategies. Antioxid. Redox Signal. 38, 68-94.

Design, Synthesis, and Evaluation of DFO-Em: A Modular Chelator with Octadentate Chelation for Optimal Zirconium-89 Radiochemistry

Zirconium-89 has quickly become a favorite radionuclide among academics and clinicians for nuclear imaging. This radiometal has a relatively long half-life, which matches the biological half-life of most antibodies, suitable decay properties for positron emission tomography (PET), and efficient and affordable cyclotron production and purification. The "gold standard" chelator for [89Zr]Zr4+ is desferrioxamine B (DFO), and although it has been used both preclinically and clinically for immunoPET with great success, it has revealed its suboptimal stability in vivo. DFO can only bind to [89Zr]Zr4+ through its six available coordination sites made up by three hydroxamic acid (HA) moieties, which is not sufficient to saturate the coordination sphere (CN 7-8). In this study, we have designed, synthesized, and characterized a new octadentate chelator we have called DFO-Em, which is an improved derivative of our previously published dodecadentate chelator DFO2. This octadentate DFO-Em chelator is smaller than DFO2 but still satisfies the coordination sphere of zirconium-89 and forms a highly stable radiometal-chelator complex. DFO-Em was synthesized by tethering a hydroxamic acid monomer to commercially available DFO using glutamic acid as a linker, providing an octadentate chelator built on a modular amino acid-based synthesis platform. Radiolabeling performance and radiochemical stability of DFO-Em were assessed in vitro by serum stability, ethylenediamine tetraacetic acid (EDTA), and hydroxyapatite challenges. Furthermore, [89Zr]Zr-(DFO-Em) and [89Zr]Zr-DFO were injected in healthy mice and measured in vivo by PET/CT imaging and ex vivo biodistribution. Additionally, the coordination of DFO-Em with Zr(IV) and its isomers was studied using density functional theory (DFT) calculations. The radiolabeling studies revealed that DFO-Em has a comparable radiolabeling profile to the gold standard chelator DFO. The in vitro stability evaluation showed that [89Zr]Zr-(DFO-Em) was significantly more stable than [89Zr]Zr-DFO, and in vivo both had similar clearance in healthy mice with a small decrease in tissue retention for [89Zr]Zr-(DFO-Em) at 24 h post injection. The DFT calculations also confirmed that Zr-(DFO-Em) can adopt highly stable 8-coordinate geometries, which along with NMR characterization suggest no fluxional behavior and the presence of a single isomer. The modular design of DFO-Em means that any natural or unnatural amino acid can be utilized as a linker to gain access to different chemistries (e.g., thiol, amine, carboxylic acid, azide) while retaining an identical coordination sphere to DFO-Em.

Lipid-Based Delivery Systems in Development of Genetic and Subunit Vaccines.

Lipidic carriers are composed of natural, synthetic, or physiological lipid/phospholipid materials. The flexibility of lipid-based delivery systems for transferring a variety of molecules such as immunomodulators, antigens, and drugs play a key role in design of effective vaccination and therapeutic strategies against infectious and non-infectious diseases. Genetic and subunit vaccines are two major groups of promising vaccines that have the potential for improving the protective potency against different diseases. These vaccine strategies rely greatly on delivery systems with various functions, including cargo protection, targeted delivery, high bioavailability, controlled release of antigens, selective induction of antigen-specific humoral or cellular immune responses, and low side effects. Lipidic carriers play a key role in local tissue distribution, retention, trafficking, uptake and processing by antigen-presenting cells. Moreover, lipid nanoparticles have successfully achieved to the clinic for the delivery of mRNA. Their broad potential was shown by the recent approval of COVID-19 mRNA vaccines. However, size, charge, architecture, and composition need to be characterized to develop a standard lipidic carrier. Regarding the major roles of lipid-based delivery systems in increasing the efficiency and safety of vaccine strategies against different diseases, this review concentrates on their recent advancements in preclinical and clinical trials.

Facile preparation of Au- and BODIPY-grafted lipid nanoparticles for synergized photothermal therapy.

Gold nanoparticles with large size exhibit preferable properties for photothermal therapy (PTT). However, the prolonged tissue retention and slow elimination of gold nanoparticles limit their therapeutic applications. Previously, gold nanoclusters carrying lipid nanoparticles (Au-LNPs) have been reported after simply mixing Au3+ with preformed diethylenetriaminepentaacetic acid lipid nanoparticles to solve this contradiction. Au-LNPs demonstrated enhanced photothermal effects in comparison to neat gold nanoparticles. To further improve the photothermal activity, we introduced the organic photothermal agent boron dipyrromethene (BODIPY) to Au-LNPs for synergistic PTT. Au- and BODIPY-grafted LNPs (AB-LNPs) were formed by simply mixing Au-LNPs with BODIPY. The BODIPY could be associated stably to Au-LNPs, and the release of BODIPY from AB-LNPs could be accelerated by laser irradiation. AB-LNPs are scalable and showed excellent photothermal effects. AB-LNPs showed enhanced cellular uptake efficiency compared to free BODIPY in 4T1 breast cancer cells. Under laser irradiation, AB-LNPs exhibited synergistic photothermal effects with significantly reduced dosage compared to monotherapy (treatments with Au-LNPs or free BODIPY alone). This study thus provides a facile and adaptive strategy for the development of a scalable and safe high-performance nanoplatform for synergistic PTT in the treatment of cancer and other diseases.

Responsive shape-shifting nanoarchitectonics and its application in tumor diagnosis and therapy.

Nanodrug delivery system has a great application in the treatment of solid tumors by virtue of EPR effect, though its success in clinics is still limited by its poor extravasation, small intratumoral accumulation, and weak tumor penetration. The shape of nanoparticles (NPs) greatly affects their circulation time, flow behavior, intratumoral amassing, cell internalization as well as tumor tissue penetration. Generally, short nanorods and 100-200nm spherical nanocarriers possess nice circulation behaviors, nanorods and nanofibers with a large aspect ratio (AR) cumulate well at tumor sites, and tiny nanospheres/disks (< 50nm) and short nanorods with a low AR achieve a favorable tumor tissue penetration. The AR and surface evenness of NPs also tune their cell contact, cell ingestion, and drug accumulation at tumor sites. Therefore, adopting stimulus-responsive shape-switching (namely, shape-shifting nanoarchitectonics) can not only ensure a good circulation and extravasation for NPs, but also and more importantly, promote their amassing, retention, and penetration in tumor tissues to maximize therapeutic efficacy. Here we review the recently developed shape-switching nanoarchitectonics of antitumoral NPs based on stimulus-responsiveness, demonstrate how successful they are in tumor shrinking and elimination, and provide new ideas for the optimization of anticancer nanotherapeutics.

Potassium homeostasis and signaling as a determinant of Echinacea species tolerance to salinity stress

Salt tolerant is strongly related to potassium (K+) retention in plant tissues under salt stress conditions. However, it is unclear for different Echinacea species. So, mechanistic basis of four Echinacea species (i.e. Echinacea purpurea, Echinacea angustifolia, Echinacea pallida, and Echinacea sanguinea) to salinity stress tolerance, and K+ retention were assessed in the present study. Non-invasive microelectrode ion flux measuring, dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR) activities, and pharmacological measurements were performed based on the standard methods. Ion flux measurements revealed higher K+ efflux in E. pallida and E. sanguinea species compared to the E. purpurea and E. angustifolia species in the elongation zone. Higher salinity-induced H+ efflux was found in the elongation zone than mature zone. However, E. angustifolia and E. purpurea had more Ca2+ influx compared to E. pallida and E. sanguinea species. Net K+ efflux decreased (> 90 %) in the presence of tetraethylammonium chloride (TEA) and GdCl3. Increasing of Ca2+ uptake and K+ loss in four Echinacea species roots were found in the presence of 0.3 mM Cu/Ascorbate (Cu/Asc). The significant role of H+-ATPase in H+ efflux was demonstrated by sodium orthovanadate. Ultimately, the physiological properties of Echinacea species have a critical role in salinity-resistant/sensitive differences. Future scientific understanding of Echinacea species physiognomies may be necessary for better understanding of the plant behavior to salinity stress.

Cell membrane-camouflaged DOX-loaded β-glucan nanoparticles for highly efficient cancer immunochemotherapy

Biomimetics plays an important role in cancer treatment since it can prolong the circulation of nanoparticles, enhance their delivery and retention in target tissues, and reduce the systemic toxicity of drugs and their carriers. In this study, we developed a biomimetic nanosystem consisting of chemotherapeutic and immunotherapeutic agents wrapped in cell membranes. Specifically, the anti-tumor drug doxorubicin (DOX) was loaded into a bacterial-derived immunomodulatory agent (low molecular weight curdlan, lCUR), and the lCUR-DOX was further wrapped in the red blood cell membrane for camouflage and prolonged circulation. The successful preparation of the lCUR-DOX@RBC nanosystem was supported by various optical and morphological characterizations. In vitro studies indicated that the nanosystem can escape uptake by macrophages, inhibit the invasion of tumor cells, and reprogram M2 macrophages with an immunosuppressive phenotype into M1 macrophages with an immunopromoting phenotype via the MAPK signaling pathway while promoting the phagocytosis of macrophages. In vivo studies showed that the nanosystem effectively inhibits tumor growth in the A-375 tumor-bearing mouse model. Taken together, the above results support further development of the lCUR-DOX@RBC platform for cancer immunochemotherapy in clinical applications.