Cell-Penetrating and Targeted Peptides Delivery Systems as Potential Pharmaceutical Carriers for Enhanced Delivery across the Blood-Brain Barrier (BBB)

ATF1 promotes ferroptosis resistance in lung cancer through enhancing mRNA stability of PROM2

BACKGROUND

Ferroptotic proteins are promising therapeutic targets for lung cancer. The PROM2 is upregulated in lung cancer and known to suppress ferroptosis. This study examined the molecular mechanisms for PROM2-induced ferroptosis resistance in lung cancer.

METHODS

Ferroptosis in lung cancer was assessed by iron kit, and transmission electron microscopy was applied to observe the changes in mitochondrial morphology. BODIPY™ was applied to test the lipid ROS, and MeRIP was performed to test the m6A modification of PROM2. RIP assay was employed for confirming the binding between METTL3 and PROM2. In addition, dual luciferase assay was employed for exploring the transcriptional regulation of ATF1 to METTL3, and the binding relation between ATF1 and METTL3 promoter region was explored by ChIP assay.

RESULTS

Expression levels of PROM2 were significantly higher in lung cancer cell lines than a noncancerous control line, and PROM2 knockdown significantly reduced both cancer cell viability and proliferation rate. In addition, PROM2 knockdown reduced xenograft tumor growth and exacerbated erastin-induced ferroptosis. Compared to PROM2 mRNA from control cells, transcripts in lung cancer cells exhibited enhanced m6A levels, and showed greater binding with METTL3. Further, ATF1 upregulated METTL3 transcription, thereby stabilizing PROM2 mRNA and increasing ferroptosis resistance.

CONCLUSION

ATF1 could promote ferroptosis resistance in lung cancer through enhancing mRNA stability of PROM2. Thus, our work might shed novel insights on discovering therapeutic strategy for lung cancer.

Enhancing hair regeneration: Recent progress in tailoring nanostructured lipid carriers through surface modification strategies

Background and purpose

Hair loss is a prevalent problem affecting millions of people worldwide, necessitating innovative and efficient regrowth approaches. Nanostructured lipid carriers (NLCs) have become a hopeful option for transporting bioactive substances to hair follicles because of their compatibility with the body and capability to improve drug absorption.

Review approach

Recently, surface modification techniques have been used to enhance hair regeneration by improving the customization of NLCs. These techniques involve applying polymers, incorporating targeting molecules, and modifying the surface charge.

Key results

The conversation focuses on how these techniques enhance stability, compatibility with the body, and precise delivery to hair follicles within NLCs. Moreover, it explains how surface-modified NLCs can improve the bioavailability of hair growth-promoting agents like minoxidil and finasteride. Furthermore, information on how surface-modified NLCs interact with hair follicles is given, uncovering their possible uses in treating hair loss conditions.

Conclusion

This review discusses the potential of altering the surface of NLCs to customize them for enhanced hair growth. It offers important information for upcoming studies on hair growth.

Brain Targeting Nanomedicines: Pitfalls and Promise

Brain diseases are the most devastating problem among the world's increasingly aging population, and the number of patients with neurological diseases is expected to increase in the future. Although methods for delivering drugs to the brain have advanced significantly, none of these approaches provide satisfactory results for the treatment of brain diseases. This remains a challenge due to the unique anatomy and physiology of the brain, including tight regulation and limited access of substances across the blood-brain barrier. Nanoparticles are considered an ideal drug delivery system to hard-to-reach organs such as the brain. The development of new drugs and new nanomaterial-based brain treatments has opened various opportunities for scientists to develop brain-specific delivery systems that could improve treatment outcomes for patients with brain disorders such as Alzheimer's disease, Parkinson's disease, stroke and brain tumors. In this review, we discuss noteworthy literature that examines recent developments in brain-targeted nanomedicines used in the treatment of neurological diseases.

Molecular determinants for brain targeting by peptides: a meta-analysis approach with experimental validation

Blood-brain barrier (BBB) peptide-shuttles (BBBpS) are able to translocate the BBB and reach the brain. Despite the importance of brain targeting in pharmacology, BBBpS are poorly characterized. Currently, their development relies on the empiric assumption that cell-penetrating peptides (CPPs), with proven ability to traverse lipid membranes, will likewise behave as a BBBpS. The relationship between CPPs/BBBpS remains elusive and, to the best of our knowledge, has not hitherto been subject to thorough experimental scrutiny. In this work, we have identified/quantified the main physicochemical properties of BBBpS and then searched for CPPs with these properties, hence potential BBBpS. The specific features found for BBBpS are: (i) small size, (ii) none or few aromatic residues, (iii) hydrophobic, and (iv) slight cationic nature. Then, we selected the 10 scoring best in an ordinary least squares analysis, and tested them in vitro and in vivo. Overall, we identified the molecular determinants for brain targeting by peptides, devised a methodology that can be used to assist in the design of peptides with potential brain penetration from amino acid residue sequences, and found four new BBBpS within the CPP library.

Peptide-conjugated Nanoparticle Platforms for Targeted Delivery, Imaging, and Biosensing Applications

Peptides have become an indispensable tool in engineering of multifunctional nanostructure platforms for biomedical applications such as targeted drug and gene delivery, imaging and biosensing. They can be covalently incorporated into a variety of nanoparticles (NPs) including polymers, metallic nanoparticles, and others. Using different bioconjugation techniques, multifunctional peptide-modified NPs can be formulated to produce therapeutical and diagnostic platforms offering high specificity, lower toxicity, biocompatibility, and stimuli responsive behavior. Targeting peptides can direct the nanoparticles into specific tissues for targeted drug and gene delivery and imaging applications due to their specificity towards certain receptors. Furthermore, due to their stimuli-responsive features, they can offer controlled release of therapeutics into desired sites of disease. In addition, peptide-based biosensors and imaging agents can provide non-invasive detection and monitoring of diseases including cancer, infectious diseases, and neurological disorders. In this review, we covered the design and formulation of recent peptide-based NP platforms, as well as their utilization in in vitro and in vivo applications such as targeted drug and gene delivery, targeting, sensing, and imaging applications. In the end, we provided the future outlook to design new peptide conjugated nanomaterials for biomedical applications.

Cell-Penetrating Peptides: Promising Therapeutics and Drug-Delivery Systems for Neurodegenerative Diseases

Currently, one of the most significant and rapidly growing unmet medical challenges is the treatment of neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). This challenge encompasses the imperative development of efficacious therapeutic agents and overcoming the intricacies of the blood-brain barrier for successful drug delivery. Here we focus on the delivery aspect with particular emphasis on cell-penetrating peptides (CPPs), widely used in basic and translational research as they enhance drug delivery to challenging targets such as tissue and cellular compartments and thus increase therapeutic efficacy. The combination of CPPs with nanomaterials such as nanoparticles (NPs) improves the performance, accuracy, and stability of drug delivery and enables higher drug loads. Our review presents and discusses research that utilizes CPPs, either alone or in conjugation with NPs, to mitigate the pathogenic effects of neurodegenerative diseases with particular reference to AD and PD.

Lipid-Based Nanoparticle Functionalization with Coiled-Coil Peptides for In Vitro and In Vivo Drug Delivery

For the delivery of drugs, different nanosized drug carriers (e.g., liposomes, lipid nanoparticles, and micelles) have been developed in order to treat diseases that afflict society. Frequently, these vehicles are formed by the self-assembly of small molecules to encapsulate the therapeutic cargo of interest. Over decades, nanoparticles have been optimized to make them more efficient and specific to fulfill tailor-made tasks, such as specific cell targeting or enhanced cellular uptake. In recent years, lipid-based nanoparticles in particular have taken center stage; however, off-targeting side effects and poor endosomal escape remain major challenges since therapies require high efficacy and acceptable toxicity.To overcome these issues, many different approaches have been explored to make drug delivery more specific, resulting in reduced side effects, to achieve an optimal therapeutic effect and a lower required dose. The fate of nanoparticles is largely dependent on size, shape, and surface charge. A common approach to designing drug carriers with targeting capability is surface modification. Different approaches to functionalize nanoparticles have been investigated since the attachment of targeting moieties plays a significant role in whether they can later interact with surface-exposed receptors of cells. To this end, various strategies have been used involving different classes of biomolecules, such as small molecules, nucleic acids, antibodies, aptamers, and peptides.Peptides in particular are often used since there are many receptors overexpressed in different specific cell types. Furthermore, peptides can be produced and modified at a low cost, enabling high therapeutic screening. Cell-penetrating peptides (CPPs) and cell-targeting peptides (CTPs) are frequently used for this purpose. Less studied in this context are fusogenic coiled-coil peptides. Lipid-based nanoparticles functionalized with these peptides are able to avoid the endolysosomal pathway; instead such particles can be taken up by membrane fusion, resulting in increased delivery of payload. Furthermore, they can be used for targeting cells/organs but are not directed at surface-exposed receptors. Instead, they recognize complementary peptide sequences, facilitating their uptake into cells.In this Account, we will discuss peptides as moieties for enhanced cytosolic delivery, targeted uptake, and how they can be attached to lipid-based nanoparticles to alter their properties. We will discuss the properties imparted to the particles by peptides, surface modification approaches, and recent examples showing the power of peptides for in vitro and in vivo drug delivery. The main focus will be on the functionalization of lipid-based nanoparticles by fusogenic coiled-coil peptides, highlighting the relevance of this concept for the development of future therapeutics.

Role of NLRP3 Inflammasome in Stroke Pathobiology: Current Therapeutic Avenues and Future Perspective

Neuroinflammation is a key pathophysiological feature of stroke-associated brain injury. A local innate immune response triggers neuroinflammation following a stroke via activating inflammasomes. The nucleotide-binding oligomerization domain leucine-rich repeat and pyrin domain-containing protein 3 (NLRP3) inflammasome has been heavily implicated in stroke pathobiology. Following a stroke, several stimuli have been suggested to trigger the assembly of the NLRP3 inflammasome. Recent studies have advanced the understanding and revealed several new players regulating NLRP3 inflammasome-mediated neuroinflammation. This article discussed recent advancements in NLRP3 assembly and highlighted stroke-induced mitochondrial dysfunction as a major checkpoint to regulating NLRP3 activation. The NLRP3 inflammasome activation leads to caspase-1-dependent maturation and release of IL-1β, IL-18, and gasdermin D. In addition, genetic or pharmacological inhibition of the NLRP3 inflammasome activation and downstream signaling has been shown to attenuate brain infarction and improve the neurological outcome in experimental models of stroke. Several drug-like small molecules targeting the NLRP3 inflammasome are in different phases of development as novel therapeutics for various inflammatory conditions, including stroke. Understanding how these molecules interfere with NLRP3 inflammasome assembly is paramount for their better optimization and/or development of newer NLRP3 inhibitors. In this review, we summarized the assembly of the NLRP3 inflammasome and discussed the recent advances in understanding the upstream regulators of NLRP3 inflammasome-mediated neuroinflammation following stroke. Additionally, we critically examined the role of the NLRP3 inflammasome-mediated signaling in stroke pathophysiology and the development of therapeutic modalities to target the NLRP3 inflammasome-related signaling for stroke treatment.

Metallic Nanocarriers for Therapeutic Peptides: Emerging Solutions Addressing the Delivery Challenges in Brain Ailments

Peptides and proteins have recently emerged as efficient therapeutic alternatives to conventional therapies. Although they emerged a few decades back, extensive exploration of various ailments or disorders began recently. The drawbacks of current chemotherapies and irradiation treatments, such as drug resistance and damage to healthy tissues, have enabled the rise of peptides in the quest for better prospects. The chemical tunability and smaller size make them easy to design selectively for target tissues. Other remarkable properties include antifungal, antiviral, anti-inflammatory, protection from hemorrhage stroke, and as therapeutic agents for gastric disorders and Alzheimer and Parkinson diseases. Despite these unmatched properties, their practical applicability is often hindered due to their weak susceptibility to enzymatic digestion, serum degradation, liver metabolism, kidney clearance, and immunogenic reactions. Several methods are adapted to increase the half-life of peptides, such as chemical modifications, fusing with Fc fragment, change in amino acid composition, and carrier-based delivery. Among these, nanocarrier-mediated encapsulation not only increases the half-life of the peptides in vivo but also aids in the targeted delivery. Despite its structural complexity, they also efficiently deliver therapeutic molecules across the blood-brain barrier. Here, in this review, we tried to emphasize the possible potentiality of metallic nanoparticles to be used as an efficient peptide delivery system against brain tumors and neurodegenerative disorders. SIGNIFICANCE STATEMENT: In this review, we have emphasized the various therapeutic applications of peptides/proteins, including antimicrobial, anticancer, anti-inflammatory, and neurodegenerative diseases. We also focused on these peptides' challenges under physiological conditions after administration. We highlighted the importance and potentiality of metallic nanocarriers in the ability to cross the blood-brain barrier, increasing the stability and half-life of peptides, their efficiency in targeting the delivery, and their diagnostic applications.

Mucosal absorption of antibody drugs enhanced by cell-penetrating peptides anchored to a platform of polysaccharides

Our previous studies demonstrated that L-octaarginine grafted onto hyaluronic acid via a tetraglycine spacer significantly enhanced intranasal absorption of protein drugs with a molecular weight (Mw) of 22 kDa or less. The present study focused on its potential as an absorption enhancer for antibody drugs with a larger Mw and the enhancement mechanism. When ranibizumab (48 kDa) alone was intranasally administered in mice, its absolute bioavailability was 0.67% on average. The mean bioavailability elevated to 6.2% under coadministration with tetraglycine-L-octaarginine-linked hyaluronic acid. A similar result was observed under substitution of ranibizumab with certolizumab pegol (91 kDa), although bioavailability itself decreased with the Mw increase, irrespective of coadministration with the hyaluronic acid derivative. Rat experiments also revealed that coadministration with the polysaccharide derivative resulted in significant enhancement of intranasal absorption of trastuzumab (148 kDa). In vitro studies using gene-knocked down cells indicated that syndecan-4-induced macropinocytosis played a crucial role on acceleration of antibody uptake into epithelial cells on the nasal mucosa, irrespective of their Mw. It appeared that neither clathrin heavy chain nor caveolin-1 involved in cellular uptake of antibodies. Tetraglycine-L-octaarginine-linked hyaluronic acid was concluded to be a promising delivery tool that possessed universal absorption-enhancing abilities independent to Mw of biologics.

Self-Entrapment of Antimicrobial Peptides in Silica Particles for Stable and Effective Antimicrobial Peptide Delivery System

Antimicrobial peptides (AMPs) have emerged as a promising solution to tackle bacterial infections and combat antibiotic resistance. However, their vulnerability to protease degradation and toxicity towards mammalian cells has hindered their clinical application. To overcome these challenges, our study aims to develop a method to enhance the stability and safety of AMPs applicable to effective drug-device combination products. The KR12 antimicrobial peptide was chosen, and in order to further enhance its delivery and efficacy the human immunodeficiency virus TAT protein-derived cell-penetrating peptide (CPP) was fused to form CPP-KR12. A new product, CPP-KR12@Si, was developed by forming silica particles with self-entrapped CPP-KR12 peptide using biomimetic silica precipitability because of its cationic nature. Peptide delivery from CPP-KR12@Si to bacteria and cells was observed at a slightly delivered rate, with improved stability against trypsin treatment and a reduction in cytotoxicity compared to CPP-KR12. Finally, the antimicrobial potential of the CPP-KR12@Si/bone graft substitute (BGS) combination product was demonstrated. CPP-KR12 is coated in the form of submicron-sized particles on the surface of the BGS. Self-entrapped AMP in silica nanoparticles is a safe and effective AMP delivery method that will be useful for developing a drug-device combination product for tissue regeneration.

Improve BBB Penetration and Cytotoxicity of Palbociclib in U87-MG Glioblastoma Cells Delivered by Dual Peptide Functionalized Nanoparticles

Palbociclib (PBC) is an FDA-approved CDK4/6 inhibitor used for breast cancer treatment. PBC has been demonstrated its ability to suppress the proliferation of glioma cells by inducing cell cycle arrest. However, the efflux transporters on the blood-brain barrier (BBB) restricts the delivery of PBC to the brain. The nano-delivery strategy with BBB-penetrating and glioma-targeting abilities was designed. Poly(lactide-co-glycolide)-poly(ethylene glycol) (PLGA-PEG) was functionalized with the potential peptide, T7 targeting peptide and/or R9 penetrating peptide, to prepare PBC-loaded nanoparticles (PBC@NPs). The size of PBC@NPs was in the range of 168.4 ± 4.3-185.8 ± 4.4 nm (PDI < 0.2), and the zeta potential ranged from -17.8 ± 1.4 mV to -14.3 ± 1.0 mV dependent of conjugated peptide. The transport of PBC@NPs across the bEnd.3 cell model was in the order of dual-peptide modified NPs > T7-peptide modified NPs > peptide-free NPs > free PBC, indicating facilitated delivery of PBC by NPs, particularly the T7/R9 dual-peptide modified NPs. Moreover, PBC@NPs significantly enhanced U87-MG glioma cell apoptosis by 2.3-6.5 folds relative to PBC, where the dual-peptide modified NPs was the most effective one. In conclusion, the PBC loaded dual-peptide functionalized NPs improved cellular uptake in bEnd.3 cells followed by targeting to U87-MG glioma cells, leading to effective cytotoxicity and promoting cell death.