Albumin uptake and processing by the proximal tubule: physiological, pathological, and therapeutic implications.

For nearly 50 years the proximal tubule (PT) has been known to reabsorb, process, and either catabolize or transcytose albumin from the glomerular filtrate. Innovative techniques and approaches have provided insights into these processes. Several genetic diseases, nonselective PT cell defects, chronic kidney disease (CKD), and acute PT injury lead to significant albuminuria, reaching nephrotic range. Albumin is also known to stimulate PT injury cascades. Thus, the mechanisms of albumin reabsorption, catabolism, and transcytosis are being reexamined with the use of techniques that allow for novel molecular and cellular discoveries. Megalin, a scavenger receptor, cubilin, amnionless, and Dab2 form a nonselective multireceptor complex that mediates albumin binding and uptake and directs proteins for lysosomal degradation after endocytosis. Albumin transcytosis is mediated by a pH-dependent binding affinity to the neonatal Fc receptor (FcRn) in the endosomal compartments. This reclamation pathway rescues albumin from urinary losses and cellular catabolism, extending its serum half-life. Albumin that has been altered by oxidation, glycation, or carbamylation or because of other bound ligands that do not bind to FcRn traffics to the lysosome. This molecular sorting mechanism reclaims physiological albumin and eliminates potentially toxic albumin. The clinical importance of PT albumin metabolism has also increased as albumin is now being used to bind therapeutic agents to extend their half-life and minimize filtration and kidney injury. The purpose of this review is to update and integrate evolving information regarding the reabsorption and processing of albumin by proximal tubule cells including discussion of genetic disorders and therapeutic considerations.

Amplifying "eat me signal" by immunogenic cell death for potentiating cancer immunotherapy.

Immunogenic cell death (ICD) is a unique mode of cell death, which can release immunogenic damage-associated molecular patterns (DAMPs) and tumor-associated antigens to trigger long-term protective antitumor immune responses. Thus, amplifying "eat me signal" during tumor ICD cascade is critical for cancer immunotherapy. Some therapies (radiotherapy, photodynamic therapy (PDT), photothermal therapy (PTT), etc.) and inducers (chemotherapeutic agents, etc.) have enabled to initiate and/or facilitate ICD and activate antitumor immune responses. Recently, nanostructure-based drug delivery systems have been synthesized for inducing ICD through combining treatment of chemotherapeutic agents, photosensitizers for PDT, photothermal transformation agents for PTT, radiosensitizers for radiotherapy, etc., which can release loaded agents at an appropriate dosage in the designated place at the appropriate time, contributing to higher efficiency and lower toxicity. Also, immunotherapeutic agents in combination with nanostructure-based drug delivery systems can produce synergetic antitumor effects, thus potentiating immunotherapy. Overall, our review outlines the emerging ICD inducers, and nanostructure drug delivery systems loading diverse agents to evoke ICD through chemoradiotherapy, PDT, and PTT or combining immunotherapeutic agents. Moreover, we discuss the prospects and challenges of harnessing ICD induction-based immunotherapy, and highlight the significance of multidisciplinary and interprofessional collaboration to promote the optimal translation of this treatment strategy.

Extracellular vesicles as modifiers of epigenomic profiles.

Extracellular vesicles (EVs), emerging as novel mediators between intercellular communication, encapsulate distinct bioactive cargoes to modulate multiple biological events, such as epigenetic remodeling. In essence, EVs and epigenomic profiles are tightly linked and reciprocally regulated. Epigenetic factors, including histone and DNA modifications, noncoding RNAs, and protein post-translational modifications (PTMs) dynamically regulate EV biogenesis to contribute to EV heterogeneity. Alternatively, EVs actively modify DNA, RNA, and histone profiles in recipient cells by delivering RNA and protein cargoes for downstream epigenetic enzyme regulation. Moreover, EVs display great potential as diagnostic markers and drug-delivery vehicles for therapeutic applications. The combination of parental cell epigenomic modification with single EV characterization would be a promising strategy for EV engineering to enhance the epidrug loading efficacy and accuracy.

In situ formed depot of elastin-like polypeptide-hirudin fusion protein for long-acting antithrombotic therapy.

Thrombosis, induced by abnormal coagulation or fibrinolytic systems, is the most common pathology associated with many life-threatening cardio-cerebrovascular diseases. However, first-line anticoagulant drugs suffer from rapid drug elimination and risk of hemorrhagic complications. Here, we developed an in situ formed depot of elastin-like polypeptide (ELP)-hirudin fusion protein with a prodrug-like feature for long-term antithrombotic therapy. Highly secretory expression of the fusion protein was achieved with the assistance of the Ffu312 tag. Integration of hirudin, ELP, and responsive moiety can customize fusion proteins with properties of adjustable in vivo retention and controllable recovery of drug bioactivity. After subcutaneous injection, the fusion protein can form a reservoir through temperature-induced coacervation of ELP and slowly diffuse into the blood circulation. The biological activity of hirudin is shielded due to the N-terminal modification, while the activated key proteases upon thrombus occurrence trigger the cleavage of fusion protein together with the release of hirudin, which has antithrombotic activity to counteract thrombosis. We substantiated that the optimized fusion protein produced long-term antithrombotic effects without the risk of bleeding in multiple animal thrombosis models.

Synergistic induction of blood-brain barrier properties.

Blood-brain barrier (BBB) models derived from human stem cells are powerful tools to improve our understanding of cerebrovascular diseases and to facilitate drug development for the human brain. Yet providing stem cell-derived endothelial cells with the right signaling cues to acquire BBB characteristics while also retaining their vascular identity remains challenging. Here, we show that the simultaneous activation of cyclic AMP and Wnt/ß-catenin signaling and inhibition of the TGF-ß pathway in endothelial cells robustly induce BBB properties in vitro. To target this interaction, we present a small-molecule cocktail named cARLA, which synergistically enhances barrier tightness in a range of BBB models across species. Mechanistically, we reveal that the three pathways converge on Wnt/ß-catenin signaling to mediate the effect of cARLA via the tight junction protein claudin-5. We demonstrate that cARLA shifts the gene expressional profile of human stem cell-derived endothelial cells toward the in vivo brain endothelial signature, with a higher glycocalyx density and efflux pump activity, lower rates of endocytosis, and a characteristic endothelial response to proinflammatory cytokines. Finally, we illustrate how cARLA can improve the predictive value of human BBB models regarding the brain penetration of drugs and targeted nanoparticles. Due to its synergistic effect, high reproducibility, and ease of use, cARLA has the potential to advance drug development for the human brain by improving BBB models across laboratories.

Modeling of spatiotemporal dynamics of ligand-coated particle flow in targeted drug delivery processes.

Nanoparticles tethered with vasculature-binding epitopes have been used to deliver the drug into injured or diseased tissues via the bloodstream. However, the extent that blood flow dynamics affects nanoparticle retention at the target site after adhesion needs to be better understood. This knowledge gap potentially underlies significantly different therapeutic efficacies between animal models and humans. An experimentally validated mathematical model that accurately simulates the effects of blood flow on nanoparticle adhesion and retention, thus circumventing the limitations of conventional trial-and-error-based drug design in animal models, is lacking. This paper addresses this technical bottleneck and presents an integrated mathematical method that derives heavily from a unique combination of a mechanics-based dispersion model for nanoparticle transport and diffusion in the boundary layers, an asperity model to account for surface roughness of endothelium, and an experimentally calibrated stochastic nanoparticle-cell adhesion model to describe nanoparticle adhesion and subsequent retention at the target site under external flow. PLGA-b-HA nanoparticles tethered with VHSPNKK peptides that specifically bind to vascular cell adhesion molecules on the inflamed vascular wall were investigated. The computational model revealed that larger particles perform better in adhesion and retention at the endothelium for the particle sizes suitable for drug delivery applications and within physiologically relevant shear rates. The computational model corresponded closely to the in vitro experiments which demonstrates the impact that model-based simulations can have on optimizing nanocarriers in vascular microenvironments, thereby substantially reducing in vivo experimentation as well as the development costs.

Topically Applied therapies for the treatment of skin disease : Past Present and Future.

The purpose of this review is to summarize essential biological, pharmaceutical and clinical aspects in the field of topically applied medicines that may help scientists when trying to develop new topical medicines. After a brief history of topical drug delivery, a review of the structure and function of the skin, routes of drug absorption and their limitations is then provided. The most prevalent diseases and current topical treatment approaches are then detailed, the organization of which reflects the key disease categories of autoimmune and inflammatory, microbial infections, skin cancers and genetic skin diseases. The complexity of topical product development through to large scale manufacture along with recommended risk mitigation approaches is then highlighted. As such topical treatments are applied externally patient preferences along with the challenges they invoke are then described and finally the future of this field of drug delivery is discussed with the emphasis on areas that are more likely to yield significant improvements over the topical medicines in current use or would expand the range of medicines and diseases treatable by this route of administration. Significance Statement This review of the key aspects the skin, its associated diseases and current treatments along with the intricacies of topical formulation development should be helpful in making judicious decisions about the development of new or improved topical medicines. These aspects include the choices of the active ingredients, formulations, the target patient populations preferences and limitations and the future with regards to new skin diseases and topical medicine approaches.

Protein click chemistry and its potential for medical applications.

A revolution in chemical biology occurred with the introduction of click chemistry. Click chemistry plays an important role in protein chemistry modifications, providing specific, sensitive, rapid, and easy-to-handle methods. Under physiological conditions, click chemistry often overlaps with bioorthogonal chemistry, defined as reactions that occur rapidly and selectively without interfering with biological processes. Click chemistry is used for the posttranslational modification of proteins based on covalent bond formations. With the contribution of click reactions, selective modification of proteins would be developed, representing an alternative to other technologies in preparing new proteins or enzymes for studying specific protein functions in different biological processes. Click-modified proteins have potential in diverse applications such as imaging, labeling, sensing, drug design, and enzyme technology. Due to the promising role of proteins in disease diagnosis and therapy, this review aims to highlight the growing applications of click strategies in protein chemistry over the last two decades, with a special emphasis on medicinal applications.

Throughput-scalable manufacturing of SARS-CoV-2 mRNA lipid nanoparticle vaccines.

Lipid nanoparticles (LNPs) are a potent delivery technology that have made it possible for the recent clinical breakthroughs in mRNA therapeutics and vaccines. A key challenge to the broader implementation of mRNA therapeutics and vaccines is the development of technology to produce precisely defined LNP formulations, with throughput that can scale from discovery to commercial manufacturing and meet the stringent manufacturing standards of the pharmaceutical industry. To address these challenges, we have developed a microfluidic chip that incorporates 1×, 10×, or 256× LNP-generating units that achieve scalable production rates of up to 17 L/h of precisely defined LNPs. Using these chips, we demonstrate that LNP physical properties and potency in vivo are unchanged as throughput is scaled. Our chips are fabricated out of silicon and glass substrates, which have excellent solvent compatibility, compatibility with pharmaceutical manufacturing, and can be fully reset and reused. SARS-CoV-2 mRNA-LNP vaccines formulated by our chips triggered potent antibody responses in a preclinical study. These results demonstrate the feasibility of directly translating microfluidic-generated LNPs to the scale necessary for commercial production.

In vivo bone marrow microenvironment siRNA delivery using lipid-polymer nanoparticles for multiple myeloma therapy.

Multiple myeloma (MM), a hematologic malignancy that preferentially colonizes the bone marrow, remains incurable with a survival rate of 3 to 6 mo for those with advanced disease despite great efforts to develop effective therapies. Thus, there is an urgent clinical need for innovative and more effective MM therapeutics. Insights suggest that endothelial cells within the bone marrow microenvironment play a critical role. Specifically, cyclophilin A (CyPA), a homing factor secreted by bone marrow endothelial cells (BMECs), is critical to MM homing, progression, survival, and chemotherapeutic resistance. Thus, inhibition of CyPA provides a potential strategy to simultaneously inhibit MM progression and sensitize MM to chemotherapeutics, improving therapeutic response. However, inhibiting factors from the bone marrow endothelium remains challenging due to delivery barriers. Here, we utilize both RNA interference (RNAi) and lipid-polymer nanoparticles to engineer a potential MM therapy, which targets CyPA within blood vessels of the bone marrow. We used combinatorial chemistry and high-throughput in vivo screening methods to engineer a nanoparticle platform for small interfering RNA (siRNA) delivery to bone marrow endothelium. We demonstrate that our strategy inhibits CyPA in BMECs, preventing MM cell extravasation in vitro. Finally, we show that siRNA-based silencing of CyPA in a murine xenograft model of MM, either alone or in combination with the Food and Drug Administration (FDA)-approved MM therapeutic bortezomib, reduces tumor burden and extends survival. This nanoparticle platform may provide a broadly enabling technology to deliver nucleic acid therapeutics to other malignancies that home to bone marrow.

Dendrimer nanosystems for adaptive tumor-assisted drug delivery via extracellular vesicle hijacking.

Drug delivery systems (DDSs) that can overcome tumor heterogeneity and achieve deep tumor penetration are challenging to develop yet in high demand for cancer treatment. We report here a DDS based on self-assembling dendrimer nanomicelles for effective and deep tumor penetration via in situ tumor-secreted extracellular vesicles (EVs), an endogenous transport system that evolves with tumor microenvironment. Upon arrival at a tumor, these dendrimer nanomicelles had their payload repackaged by the cells into EVs, which were further transported and internalized by other cells for delivery "in relay." Using pancreatic and colorectal cancer-derived 2D, 3D, and xenograft models, we demonstrated that the in situ-generated EVs mediated intercellular delivery, propagating cargo from cell to cell and deep within the tumor. Our study provides a new perspective on exploiting the intrinsic features of tumors alongside dendrimer supramolecular chemistry to develop smart and effective DDSs to overcome tumor heterogeneity and their evolutive nature thereby improving cancer therapy.

Self-powered, light-controlled, bioresorbable platforms for programmed drug delivery.

Degradable polymer matrices and porous scaffolds provide powerful mechanisms for passive, sustained release of drugs relevant to the treatment of a broad range of diseases and conditions. Growing interest is in active control of pharmacokinetics tailored to the needs of the patient via programmable engineering platforms that include power sources, delivery mechanisms, communication hardware, and associated electronics, most typically in forms that require surgical extraction after a period of use. Here we report a light-controlled, self-powered technology that bypasses key disadvantages of these systems, in an overall design that is bioresorbable. Programmability relies on the use of an external light source to illuminate an implanted, wavelength-sensitive phototransistor to trigger a short circuit in an electrochemical cell structure that includes a metal gate valve as its anode. Consequent electrochemical corrosion eliminates the gate, thereby opening an underlying reservoir to release a dose of drugs by passive diffusion into surrounding tissue. A wavelength-division multiplexing strategy allows release to be programmed from any one or any arbitrary combination of a collection of reservoirs built into an integrated device. Studies of various bioresorbable electrode materials define the key considerations and guide optimized choices in designs. In vivo demonstrations of programmed release of lidocaine adjacent the sciatic nerves in rat models illustrate the functionality in the context of pain management, an essential aspect of patient care that could benefit from the results presented here.

A bioengineered probiotic for the oral delivery of a peptide Kv1.3 channel blocker to treat rheumatoid arthritis.

Engineered microbes for the delivery of biologics are a promising avenue for the treatment of various conditions such as chronic inflammatory disorders and metabolic disease. In this study, we developed a genetically engineered probiotic delivery system that delivers a peptide to the intestinal tract with high efficacy. We constructed an inducible system in the probiotic Lactobacillus reuteri to secrete the Kv1.3 potassium blocker ShK-235 (LrS235). We show that LrS235 culture supernatants block Kv1.3 currents and preferentially inhibit human T effector memory (TEM) lymphocyte proliferation in vitro. A single oral gavage of healthy rats with LrS235 resulted in sufficient functional ShK-235 in the circulation to reduce inflammation in a delayed-type hypersensitivity model of atopic dermatitis mediated by TEM cells. Furthermore, the daily oral gavage of LrS235 dramatically reduced clinical signs of disease and joint inflammation in rats with a model of rheumatoid arthritis without eliciting immunogenicity against ShK-235. This work demonstrates the efficacy of using the probiotic L. reuteri as a novel oral delivery platform for the peptide ShK-235 and provides an efficacious strategy to deliver other biologics with great translational potential.

Remote control of mechanochemical reactions under physiological conditions using biocompatible focused ultrasound.

External control of chemical reactions in biological settings with spatial and temporal precision is a grand challenge for noninvasive diagnostic and therapeutic applications. While light is a conventional stimulus for remote chemical activation, its penetration is severely attenuated in tissues, which limits biological applicability. On the other hand, ultrasound is a biocompatible remote energy source that is highly penetrant and offers a wide range of functional tunability. Coupling ultrasound to the activation of specific chemical reactions under physiological conditions, however, remains a challenge. Here, we describe a synergistic platform that couples the selective mechanochemical activation of mechanophore-functionalized polymers with biocompatible focused ultrasound (FUS) by leveraging pressure-sensitive gas vesicles (GVs) as acousto-mechanical transducers. The power of this approach is illustrated through the mechanically triggered release of covalently bound fluorogenic and therapeutic cargo molecules from polymers containing a masked 2-furylcarbinol mechanophore. Molecular release occurs selectively in the presence of GVs upon exposure to FUS under physiological conditions. These results showcase the viability of this system for enabling remote control of specific mechanochemical reactions with spatiotemporal precision in biologically relevant settings and demonstrate the translational potential of polymer mechanochemistry.

Synthetic molecular motor activates drug delivery from polymersomes.

The design of stimuli-responsive systems in nanomedicine arises from the challenges associated with the unsolved needs of current molecular drug delivery. Here, we present a delivery system with high spatiotemporal control and tunable release profiles. The design is based on the combination of an hydrophobic synthetic molecular rotary motor and a PDMS-b-PMOXA diblock copolymer to create a responsive self-assembled system. The successful incorporation and selective activation by low-power visible light (λ = 430 nm, 6.9 mW) allowed to trigger the delivery of a fluorescent dye with high efficiencies (up to 75%). Moreover, we proved the ability to turn on and off the responsive behavior on demand over sequential cycles. Low concentrations of photoresponsive units (down to 1 mol% of molecular motor) are shown to effectively promote release. Our system was also tested under relevant physiological conditions using a lung cancer cell line and the encapsulation of an Food and Drug Administration (FDA)-approved drug. Similar levels of cell viability are observed compared to the free given drug showing the potential of our platform to deliver functional drugs on request with high efficiency. This work provides an important step for the application of synthetic molecular machines in the next generation of smart delivery systems.

Regenerative engineering of long bones using the small molecule forskolin.

Bone grafting procedures have become increasingly common in the United States, with approximately 500,000 cases occurring each year at a societal cost exceeding $2.4 billion. Recombinant human bone morphogenetic proteins (rhBMPs) are therapeutic agents that have been widely used by orthopedic surgeons to stimulate bone tissue formation alone and when paired with biomaterials. However, significant limitations such as immunogenicity, high production cost, and ectopic bone growth from these therapies remain. Therefore, efforts have been made to discover and repurpose osteoinductive small-molecule therapeutics to promote bone regeneration. Previously, we have demonstrated that a single-dose treatment with the small-molecule forskolin for just 24 h induces osteogenic differentiation of rabbit bone marrow-derived stem cells in vitro, while mitigating adverse side effects attributed with prolonged small-molecule treatment schemes. In this study, we engineered a composite fibrin-PLGA [poly(lactide-co-glycolide)]-sintered microsphere scaffold for the localized, short-term delivery of the osteoinductive small molecule, forskolin. In vitro characterization studies showed that forskolin released out of the fibrin gel within the first 24 h and retained its bioactivity toward osteogenic differentiation of bone marrow-derived stem cells. The forskolin-loaded fibrin-PLGA scaffold was also able to guide bone formation in a 3-mo rabbit radial critical-sized defect model comparable to recombinant human bone morphogenetic protein-2 (rhBMP-2) treatment, as demonstrated through histological and mechanical evaluation, with minimal systemic off-target side effects. Together, these results demonstrate the successful application of an innovative small-molecule treatment approach within long bone critical-sized defects.

Batteryless implantable device with built-in mechanical clock for automated and precisely timed drug administration.

Adherence to medication plays a crucial role in the effective management of chronic diseases. However, patients often miss their scheduled drug administrations, resulting in suboptimal disease control. Therefore, we propose an implantable device enabled with automated and precisely timed drug administration. Our device incorporates a built-in mechanical clock movement to utilize a clockwork mechanism, i.e., a periodic turn of the hour axis, enabling automatic drug infusion at precise 12-h intervals. The actuation principle relies on the sophisticated design of the device, where the rotational movement of the hour axis is converted into potential mechanical energy and is abruptly released at the exact moment for drug administration. The clock movement can be charged either automatically by mechanical agitations or manually by winding the crown, while the device remains implanted, thereby enabling the device to be used permanently without the need for batteries. When tested using metoprolol, an antihypertensive drug, in a spontaneously hypertensive animal model, the implanted device can deliver drug automatically at precise 12-h intervals without the need for further attention, leading to similarly effective blood pressure control and ultimately, prevention of ventricular hypertrophy as compared with scheduled drug administrations. These findings suggest that our device is a promising alternative to conventional methods for complex drug administration.

Reverse-QTY code design of active human serum albumin self-assembled amphiphilic nanoparticles for effective anti-tumor drug doxorubicin release in mice.

Human serum albumin (HSA) is a highly water-soluble protein with 67% alpha-helix content and three distinct domains (I, II, and III). HSA offers a great promise in drug delivery with enhanced permeability and retention effect. But it is hindered by protein denaturation during drug entrapment or conjugation that result in distinct cellular transport pathways and reduction of biological activities. Here we report using a protein design approach named reverse-QTY (rQTY) code to convert specific hydrophilic alpha-helices to hydrophobic to alpha-helices. The designed HSA undergo self-assembly of well-ordered nanoparticles with highly biological actives. The hydrophilic amino acids, asparagine (N), glutamine (Q), threonine (T), and tyrosine (Y) in the helical B-subdomains of HSA were systematically replaced by hydrophobic leucine (L), valine (V), and phenylalanine (F). HSArQTY nanoparticles exhibited efficient cellular internalization through the cell membrane albumin binding protein GP60, or SPARC (secreted protein, acidic and rich in cysteine)-mediated pathways. The designed HSArQTY variants displayed superior biological activities including: i) encapsulation of drug doxorubicin, ii) receptor-mediated cellular transport, iii) tumor cell targeting, and iv) antitumor efficiency compare to denatured HSA nanoparticles. HSArQTY nanoparticles provided superior tumor targeting and antitumor therapeutic effects compared to the albumin nanoparticles fabricated by antisolvent precipitation method. We believe that the rQTY code is a robust platform for specific hydrophobic modification of functional hydrophilic proteins with clear-defined binding interfaces.

Patient Centricity Driving Formulation Innovation: Improvements in Patient Care Facilitated by Novel Therapeutics and Drug Delivery Technologies.

Innovative formulation technologies can play a crucial role in transforming a novel molecule to a medicine that significantly enhances patients' lives. Improved mechanistic understanding of diseases has inspired researchers to expand the druggable space using new therapeutic modalities such as interfering RNA, protein degraders, and novel formats of monoclonal antibodies. Sophisticated formulation strategies are needed to deliver the drugs to their sites of action and to achieve patient centricity, exemplified by messenger RNA vaccines and oral peptides. Moreover, access to medical information via digital platforms has resulted in better-informed patient groups that are requesting consideration of their needs during drug development. This request is consistent with health authority efforts to upgrade their regulations to advance age-appropriate product development for patients. This review describes formulation innovations contributingto improvements in patient care: convenience of administration, preferred route of administration, reducing dosing burden, and achieving targeted delivery of new modalities.

Local Cancer Recurrence: The Realities, Challenges, and Opportunities for New Therapies.

Locoregional recurrence negatively impacts both long-term survival and quality of life for several malignancies. For appropriate-risk patients with an isolated, resectable, local recurrence, surgery represents the only potentially curative therapy. However, oncologic outcomes remain inferior for patients with locally recurrent disease even after macroscopically complete resection. Unfortunately, these operations are often extensive, with significant perioperative morbidity and mortality. This review highlights selected malignancies (mesothelioma, sarcoma, lung cancer, breast cancer, rectal cancer, and peritoneal surface malignancies) in which surgical resection is a key treatment modality and local recurrence plays a significant role in overall oncologic outcome with regard to survival and quality of life. For each type of cancer, the current, state-of-the-art treatment strategies and their outcomes are assessed. The need for additional therapeutic options is presented given the limitations of the current standard therapies. New and emerging treatment modalities, including polymer films and nanoparticles, are highlighted as potential future solutions for both prevention and treatment of locally recurrent cancers. Finally, the authors identify additional clinical and research opportunities and propose future research strategies based on the various patterns of local recurrence among the different cancers.