Lipid nanoparticles (LNPs) have become an important platform for the delivery of RNA therapeutics, including messenger RNA (mRNA) and small interfering RNA (siRNA). However, most clinically approved LNP formulations exhibit strong liver tropism following systemic administration, which limits efficient delivery to extrahepatic tissues. This inherent biodistribution profile has therefore been recognized as a key challenge for expanding the therapeutic applications of RNA nanomedicine. Recent efforts have focused on engineering functionalized LNP systems to improve delivery specificity beyond the liver. Surface modification with targeting ligands—such as antibodies, peptides, and nucleic acid aptamers—can promote receptor-mediated uptake by specific immune cell populations, including macrophages, dendritic cells and T lymphocytes. In parallel, advances in lipid design have improved intracellular RNA delivery by facilitating endosomal escape. These developments have broadened the potential use of RNA nanomedicine for inflammatory disorders, including autoimmune diseases, neuroinflammation, and cardiovascular inflammation. Functionalized LNPs are also being investigated for in vivo engineering of immune cells. This review summarizes current strategies for designing functionalized LNP systems, highlights their emerging applications in immune and inflammatory diseases, and discusses key challenges for clinical translation.

Estrogen-related receptor-α (ERRα; NR3B1) is an orphan nuclear receptor that drives the progression of several cancers. To develop novel ERRα-targeting therapeutics, we designed and evaluated the function of a new compound, PAMT-001, which interacts with ERRα and effectively suppresses tumorigenesis. We demonstrated a significant interaction between ERRα and PAMT-001 using protein-small molecule binding assays and luciferase assays. Although PAMT-001 exhibited lower activity compared to the established ERRα inverse agonist XCT-790, it showed stronger anticancer effects against both hematological and solid tumors. Mechanistically, PAMT-001 promoted combined cell death mechanisms in tumors. It disrupted mitochondrial respiratory function and structure, leading to excessive production of reactive oxygen species and endoplasmic reticulum stress, ultimately resulting in apoptotic cell death. Additionally, PAMT-001 induced excessive autophagy, contributing to cancer cell death, as well as gasdermin E-mediated pyroptosis in acute myeloid leukemia and colon cancer cells. Furthermore, PAMT-001 demonstrated potential for use in precision medicine, particularly for patients with chemotherapy-resistant and NPM1-mutated acute myeloid leukemia. PAMT-001 is a potent ERRα-targeting anticancer agent capable of inducing anticancer effects through pyroptosis, autophagic cell death, and apoptosis-a newly termed mechanism referred to as "PAAoptosis." It holds significant potential for the treatment of both hematological and solid cancers.

BACKGROUND:Ischemia-reperfusion (I/R) injury remains a major cause of partial skin flap necrosis following microsurgical reconstruction. This study evaluates the therapeutic potential of bovine colostrum-derived extracellular vesicles (C-EVs) as a scalable, cell-free alternative for enhancing skin flap survival. METHODS:Twenty-four Sprague-Dawley rats were randomly assigned to Sham, Control, and Exosome groups (n=8). A 3×6-cm 2 superficial inferior epigastric artery (SIEA) flap was elevated in all animals. The Control and Exosome groups were subjected to 8 hours of ischemia followed by reperfusion, while the Sham group underwent elevation alone. The Exosome group received 200 μg of C-EVs subcutaneously on Days 0 and 3, while Control and Sham groups received PBS. On Day 7, flap survival was evaluated via macroscopic analysis and laser Doppler perfusion imaging. Histological and immunohistochemical analyses were performed on tissue harvested from the standardized watershed zone to evaluate microvessel density (MVD), pro-inflammatory cytokines, and macrophage polarization. RESULTS:C-EVs significantly improved flap survival compared to the Control group (70.50±8.24 vs. 51.75±3.62 percent, p<0.05) and enhanced vascular perfusion (70.88±5.08 vs. 58.88±6.85 percent, p<0.05). Quantitative IHC analysis revealed that C-EV treatment significantly increased MVD (149.00±3.09 vs. 71.88±6.79 vessels/mm 2, p<0.01) and suppressed pro-inflammatory cytokine expression. Furthermore, C-EVs promoted M2 macrophage polarization, evidenced by a significantly lower CD86/CD206 ratio (p<0.01). CONCLUSIONS:This study provides early-stage preliminary evidence in a controlled rat model that C-EVs can mitigate I/R injury and improve skin flap survival. Given the proof-of-concept nature of these findings, further investigation in larger models is required to determine their clinical applicability.

Despite extensive pharmacological efforts to apply targeted protein degradation (TPD) across diverse disease contexts, strategies enabling its convenient and practical use remain limited. To expand the therapeutic landscape of TPD, we herein design a proteolysis-targeting chimera (PROTAC) degrader with excellent compatibility in aqueous hydrogels, thereby establishing a sprayable system for dermatological conditions. This sprayable hydrogel allows user-friendly topical application and ensures prolonged skin retention of the PROTAC through robust tissue adhesion. Targeted proteolysis of the androgen receptor (AR) generates a pro-regenerative microenvironment by inducing a macrophage phenotypic shift from the proinflammatory M1 to the anti-inflammatory M2 state. Consequently, topical spraying of the PROTAC-loaded hydrogel accelerates skin regeneration, highlighting its potential as a versatile therapeutic platform for both wound repair and psoriasis management. Extending beyond conventional PROTAC research, which has primarily focused on target identification and chemical optimization, this study introduces a practical design strategy for translating TPD into regenerative medicine.

Riboswitches are RNAs that recognize ligands and regulate gene expression. They are typically located in the untranslated region of bacterial messenger RNA and consist of an aptamer and an expression platform. In this study, we examine the folding pathway of the Vc2 (Vibrio cholerae) riboswitch aptamer domain, which targets the bacterial secondary messenger cyclic-di-GMP. We demonstrated by nuclear magnetic resonance (NMR) and isothermal titration calorimetry that the stable folding of the Vc2 riboswitch requires an adequate supply of Mg2+, Na+ and K+ ions. We found that Mg2+ has a crucial role in the pre-folding of the aptamer, while K+ is essential for establishing the long-range G-C interactions and stabilizing the ligand binding pocket. Precise imino proton assignments revealed the progressive folding of the aptamer. The results indicate that the P2 helix consists of weaker and more dynamic base pairs compared to the P1b helix, allowing the rearrangement of the base pairs in the P2 helix during the folding process required for effective ligand recognition. This study provides a profound understanding riboswitch architecture and dynamics at the atomic level under physiological conditions as well as structural information on apo-state RNA.

TRIpartite Motif-containing 72 (TRIM72, also known as MG53), a RING-type E3 ubiquitin ligase, is critical for plasma membrane repair. Like other TRIM family proteins, TRIM72 has a conserved architecture comprising RING, B-box, coiled-coil, and C-terminal PRY-SPRY domains. While the coiled-coil domain mediates homo-oligomerization, its specific contribution to the membrane repair machinery remains unclear. In this study, we characterized the structural and dynamic properties of the TRIM72 coiled-coil domain, aiming to elucidate its contribution to membrane association. Small-angle X-ray scattering and molecular dynamics simulations revealed that the coiled-coil domain exhibits significant flexibility, including directional movements perpendicular to the membrane. Cryo-electron microscopy further demonstrated that coiled-coil-mediated oligomerization facilitated the tethering of adjacent liposomes. These findings highlight the role of the coiled-coil domain in supporting higher-order assembly on membranes, providing mechanistic insights into the TRIM72-mediated membrane repair.

In light of the burgeoning successes of cancer immunotherapy, glioblastoma (GBM) remains refractory due to an immunosuppressive microenvironment originating from its molecular heterogeneity. Thus, identifying promising therapeutic targets for treating GBM and discovering methodologies to effectively regulate them is still a tremendous challenge. Here we describe photodynamic protein tyrosine phosphatase 1B (PTP1B) proteolysis mediated by a proteolysis-targeting chimera (PROTAC) nanoassembly. The PTP1B-targeting PROTAC is conjugated with a photosensitizer via a cathepsin B (Cat B)-cleavable peptide, which spontaneously forms nanoassemblies due to intermolecular π-π stacking interactions. In GBM models, PROTAC nanoassemblies significantly accumulate in the tumor region across the disrupted blood-brain barrier (BBB), triggering a burst release of the photosensitizer and active PROTAC by Cat B-mediated enzymatic cleavage. Upon laser irradiation, photodynamic therapy (PDT) synergizes with PROTAC-mediated PTP1B proteolysis to induce potent immunogenic cell death (ICD) in tumor cells. Subsequently, persistent PTP1B degradation by nanoassemblies in Cat B-overexpressed intratumoral T cells downregulates exhaustion markers, reinvigorating their functionality. These sequential processes of photodynamic PTP1B proteolysis ultimately augment T cell-mediated antitumor immunity as well as protective immunity, completely eradicating the primary GBM and preventing its recurrence. Overall, our findings underscore the therapeutic potential of combining PDT with PROTAC activity for GBM immunotherapy.

Human spliceosome-associated factor 3, SART3, is a key factor in spliceosome recycling and engages with U6 small nuclear RNA (snRNA) to promote the formation of the U4/U6 small nuclear ribonucleoprotein complex. Unlike its counterpart U4/U6 snRNA-associated-splicing factor PRP24 (Prp24) from Saccharomyces cerevisiae, which uses four RNA recognition motifs (RRMs) for the U6 snRNA interaction, SART3 has two RRMs at its C terminus. Here, we demonstrate that SART3 binds U6 snRNA as a dimer, and four RRM subunits recognize the asymmetric bulge of U6 snRNA. SART3 RRMs adopt a tandem βαββαβ motif of the canonical RRM fold to interact with the U6 bulge region via a conserved electropositive surface. We identified the cognate U6 elements that specifically bind SART3 RRM1, which is distinct from the Prp24-U6 interactions in yeast. Our findings suggest a divergent RRM binding mechanism for U6 snRNA recognition during spliceosome assembly and recycling.

Autophagy is a vital process that enables plants to adapt to various environmental changes. During heat stress (HS), misfolded and denatured proteins accumulate in cells, necessitating autophagy for their removal. Here, we show that a core autophagy component ATG8a is targeted for degradation via the Arg/N-degron pathway. ATG8a is expressed as two alternatively spliced transcripts encoding ATG8a isoforms, namely ATG8a(S) and ATG8a(L), with distinct N-termini. While ATG8a(S) remains stable, ATG8a(L) is N-terminally processed to expose the Arg/N-degron, leading to its degradation. Ubiquitin protein ligase E3 component N-recognin 7 (UBR7), identified as an N-recognin, is responsible for ubiquitination and proteasomal degradation of ATG8a(L). Notably, ATG8a(S) and ATG8a(L) show dynamic expression patterns, fluctuating ATG8a levels during the HS and recovery periods. Our findings highlight the crucial role of ATG8a turnover in conferring thermotolerance, which is governed by Arg/N-degron-mediated regulation. Understanding the molecular basis of ATG8a stability will provide valuable insights into plant resilience to HS under changing climatic conditions.

Peptide/antibody–drug conjugates (PADCs) are an emerging class of targeted therapeutics that leverage the specificity of peptide or antibody ligands to deliver potent small‐molecule payloads selectively to disease sites via cleavable linkers. This design combines high target affinity with controlled local activation and minimal systemic toxicity. To date, 15 antibody–drug conjugates and 3 peptide–drug conjugates have been approved by the FDA; however, all are indicated exclusively for oncology. Consequently, the development of PADCs has primarily focused on cancer, with relatively few comprehensive reviews addressing their potential in non‐oncological applications. In this review, the therapeutic potential of PADCs as a targeted strategy for treating inflammatory diseases—such as inflammatory bowel disease, chronic kidney inflammation, and arthritis—is explored by detailing how engineered peptide or antibody ligands recognize upregulated pathological markers in inflamed microenvironments and enable site‐specific drug release through stimuli‐responsive linkers. By consolidating recent advances, this review broadens the therapeutic scope of PADCs and highlights their promise as next‐generation immunomodulators for targeted treatment of inflammatory diseases.

Eukaryotic N-degron pathways are proteolytic systems with the ability to recognize specific N-terminal residues of substrate proteins, which are essential parts of their degradation signals. Domains, referred to as UBR boxes, of several E3 ubiquitin ligases can recognize basic N-terminal residues as N-degrons. UBR6 is among the seven mammalian UBR family proteins containing the UBR box domain. However, the recognition of basic type-1 N-degrons by UBR6 is still not well understood. The crystal structure of the UBR box from human UBR6 revealed zinc-mediated dimerization, a structural feature distinct from other monomeric UBR boxes. Furthermore, its folding pattern differed from that of the UBR fold, although the sequences aligned well with those of other UBR boxes. In this study, we re-determined the structure of the UBR box from human UBR6 to investigate whether the unusual domain-swapped dimer was structurally relevant. The newly determined UBR box of UBR6 at 1.5 Å resolution was a monomer with a classical UBR fold. Our structure was compared with previously reported structures of UBR boxes, and its structural features were further analyzed using N-degron binding assays.

PROTEOLYSIS1 (PRT1), an N-recognin of Arabidopsis thaliana, recognizes the N-terminal aromatic hydrophobic residue (Tyr/Phe/Trp) of its substrates and ubiquitylates them for degradation by the ubiquitin-proteasome system. Herein, we report the structures of the ZZ domain of PRT1 (PRT1ZZ) in complex with bulky hydrophobic N-degron peptides. Unlike other ZZ domains, PRT1ZZ has an unusual binding site with two hydrophobic regions. The N-terminal aromatic residues of N-degrons interact with Ile333 and Phe352 in the flexible loops, which undergo a conformational change. Notably, we identify a third residue from the N-terminus of the substrate that participates in the hydrophobic network with PRT1ZZ. Moreover, AlphaFold prediction and biochemical assays revealed that the tandem RING1 and RING2 domains of PRT1 interact intramolecularly. The dimeric RING domains in a single protein represent a unique feature among the RING-type E3 ligases. The biochemical assays using the N-terminal tyrosine-exposed substrate, BIG BROTHER, show that the intramolecular RING dimer is essential for PRT1's robust activity. Therefore, this study expands our knowledge of the structural repertoire in the N-degron pathway and provides insights into the regulation of E3 ligases containing tandem RING domains.

Eukaryotic cells have evolved sophisticated quality control mechanisms to eliminate aggregation-prone proteins that compromise cellular health. Central to this defense is the ubiquitin-proteasome system, where UBR4 acts as an essential E4 ubiquitin ligase, amplifying degradation marks on defective proteins. Cryo-electron microscopy analysis of UBR4 in complex with its cofactors KCMF1 and CALM1 reveals a massive 1.3-megadalton ring structure, featuring a central substrate-binding arena and flexibly attached catalytic units. Our structure shows how UBR4 binds substrate and extends lysine-48-specific ubiquitin chains. Efficient substrate targeting depends on both preubiquitination and specific N-degrons, with KCMF1 acting as a key substrate filter. The architecture of the E4 megacomplex is conserved across eukaryotes, but species-specific adaptations allow UBR4 to perform its precisely tuned quality control function in diverse cellular environments.

RING-type E3 ubiquitin ligases are functional multidomain proteins involved in diverse eukaryotic cellular processes. A major subfamily of RING-type ligases is the tripartite motif (TRIM)-containing protein family, whose members contain RING, B-box, coiled-coil, and variable C-terminal domains. Although the roles of individual TRIM domains are well understood, the function of the coiled-coil domain remains unclear owing to its structural complexity. In this study, we investigated the structural details of the coiled-coil domain of TRIM72 to elucidate its role in facilitating interactions with both concave and convex membranes. Cooperative interactions of the coiled-coil/coiled-coil and B-box/B-box domains were found to drive oligomerization, aiding in the recognition of phospholipid layers by the PRYSPRY domains. These insights provide a fundamental basis for understanding TRIM family E3 ligases and highlight their conserved molecular architecture and pattern recognition capabilities through higher-order assembly.

The NS1 binding protein, known for interacting with the influenza A virus protein, is involved in RNA processing, cancer, and nerve cell growth regulation. However, its role in stress response independent of viral infections remains unclear. This study investigates NS1 binding protein's function in regulating stress granules during oxidative stress through interactions with GABARAP subfamily proteins. We find that NS1 binding protein localizes to stress granules, interacting with core components, GABARAP proteins, and p62, a protein involved in autophagy. In cells lacking NS1 binding protein, stress granule dynamics are altered, and p62 ubiquitination is increased, suggesting impaired stress granule degradation. Overexpression of NS1 binding protein reduces p62 ubiquitination. In amyotrophic lateral sclerosis patient-derived neurons, reduced NS1 binding protein and p62 disrupt stress granule morphology. These findings identify NS1 binding protein as a negative regulator of p62 ubiquitination and a facilitator of GABARAP recruitment to stress granules, implicating it in stress granule regulation and amyotrophic lateral sclerosis pathogenesis.

ISG15 is an interferon-stimulated ubiquitin-like protein (UBL) with multifaceted roles as a posttranslational modifier in ISG15 conjugation (ISGylation). However, the mechanistic consequences of ISGylation in cancer have not been fully elucidated, largely due to a lack of knowledge on the ISG15 target repertoire. Here, we identified SIRT1, a nicotinamide adenine dinucleotide (NAD+)-dependent protein deacetylase, as a new target for ISGylation. SIRT1 ISGylation impairs the association of SIRT1 with its negative regulator, deleted in breast cancer 1 (DBC1), which unleashes SIRT1 from its inactive state and leads to an increase in its deacetylase activity. Importantly, SIRT1 ISGylation promoted lung cancer progression and limited lung cancer cell sensitivity to DNA damage-based therapeutics in vivo and in vitro models. The levels of ISG15 mRNA and protein were significantly higher in lung cancer tissues than in adjacent normal tissues. Accordingly, elevated expression of SIRT1 and ISG15 was associated with poor prognosis in lung cancer patients, a finding that could be translated for lung cancer patient stratification and disease outcome evaluation. Taken together, our findings provide a mechanistic understanding of the regulatory effect of SIRT1 ISGylation on tumor progression and therapeutic efficacy in lung cancer. Interferon-stimulated gene 15 (ISG15) is known to influence tumor growth and severity. Young Joo Jeon at Chungnam National University College of Medicine, Daejon, South Korea, and co-workers found that ISG15 can conjugate to another protein, SIRT1, which also affects tumor growth and response to treatment. The research, conducted on human cells, mice, and human lung cancer tissues, revealed that when ISG15 conjugates to SIRT1, it boosts SIRT1's activity, encouraging tumor growth and reducing the effectiveness of a chemotherapy drug. Additionally, high levels of SIRT1 and ISG15 in lung cancer tissues were linked to worse outcomes. The study suggests that focusing on understanding of the regulatory effect of ISG15 conjugation to SIRT1 could enhance cancer treatments. This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author.

AbstractPoxviruses are implicated in a variety of infectious diseases; however, little is known about the molecular mechanisms that underlie the immune response during poxvirus infection. We investigated the function and mechanisms of the monkeypox virus envelope protein (A30L) and its core peptide (IAMP29) during the activation of innate immune responses. The A30L protein and its core peptide, IAMP29 (a 29-amino-acid inflammasome-activating peptide encompassing His40 to Asp69 of A30L), strongly activated the nucleotide-binding oligomerization domain, leucine rich repeat and pyrin domain-containing 3 (NLRP3) inflammasome by inducing the production of mitochondrial reactive oxygen species in human monocytes. Specifically, IAMP29 triggered metabolic reprogramming toward glycolysis and interacted with pyruvate kinase M isoforms (PKM1 and PKM2), thus activating the NLRP3 inflammasome and interleukin (IL)-1β production in human monocytes and murine macrophages. In human primary monocyte-derived macrophages, IAMP29-induced inflammasome activation promoted an antimicrobial response to rapidly growing non-tuberculous mycobacteria. Furthermore, IAMP29 exhibited cytotoxic activity against leukemia cells, which was mediated by pyroptosis and apoptosis. These findings provide insights into the immunological function of the poxvirus envelope peptide and suggest its therapeutic potential.