Sepsis and rheumatoid arthritis (RA) are distinct yet mechanistically related conditions commonly driven by dysregulated inflammatory responses. Here, we explored the counterintuitive hypothesis that an epitope from a deleterious anti-tetranectin (TN) antibody (mAb9) could hold unforeseen therapeutic potential. By mapping mAb9’s epitope to P2 (residues 55–70), a region crucial for TN’s protective functions, we developed P2-1, a water-soluble derivative as a targeted therapy. We then employed animal models of sepsis (cecal ligation and puncture) and arthritis (collagen antibody-induced arthritis) to evaluate the therapeutic effects of P2, P2-1, and a procathepsin L (pCTS-L)-neutralizing antibody by assessing septic survival, arthritis severity, pain sensitivity, and joint tissue histology. In parallel, we utilized a surface plasmon resonance (SPR) assay and computational modeling to examine the P2-1/high mobility group box 1 (HMGB1) interaction. Finally, we elucidate the effect of P2-1 on the HMGB1-induced release of pCTS-L and other cytokines and chemokines using primary human peripheral blood mononuclear cells (PBMCs). P2-1 significantly improved survival and reduced systemic inflammation in a sepsis model, and attenuated arthritis severity and pain sensitivity in an RA model, even with therapeutic administration after disease onset. Mechanistically, P2-1 exhibited high-affinity binding to HMGB1 and selectively suppressed HMGB1-induced cathepsin L (Ctsl) mRNA upregulation and pCTS-L secretion from human immune cells, crucially without perturbing other HMGB1-induced cytokines and chemokines. We further validated pCTS-L as a therapeutic target by demonstrating that a neutralizing antibody conferred potent antiarthritic effects, reducing joint inflammation, pain, and structural damage. Our findings introduce a paradigm-shifting drug discovery strategy that transforms insights from harmful antibody action into targeted therapeutics for the HMGB1-pCTS-L axis. This approach not only delivers P2-1 as a potent therapy but also establishes pCTS-L as a crucial mediator in inflammatory diseases such as sepsis and RA.

High Mobility Group Box 1 (HMGB1) and Procathepsin L (pCTS-L) are crucial inflammatory mediators, yet their immunomodulating properties in human immune cells have not been systematically compared. This study employed RNA-sequencing to comparatively analyze their transcriptional effects on primary human peripheral blood mononuclear cells (PBMCs). Our findings demonstrate that while both mediators elicited significant transcriptional changes indicative of robust inflammatory responses, HMGB1 consistently induced a more extensive and diversified inflammatory program. Specifically, at a lower concentration of 0.5 µg/ml, HMGB1 triggered nearly four times more differentially expressed genes (DEGs) than pCTS-L (2.0 µg/ml). Despite this quantitative difference, an overlap of 412 DEGs (272 upregulated, 140 downregulated) revealed shared core inflammatory pathways, including the extensive upregulation of pro-inflammatory cytokines (e.g., IL1A, IL1B, and IL6), chemokines (e.g., CCL2 and CXCL1), and S100 proteins (e.g., S100A8, S100A9, and S100A12). Both mediators also converged on activating the non-canonical NF-κB pathway, evidenced by NFKB2 and RELB upregulation, suggesting a common underlying regulatory mechanism. Notably, HMGB1 uniquely upregulated CASP4 and CASP5—key components of the non-canonical inflammasome pathway—and a broader spectrum of cytokines and chemokines (e.g., IL23A, CXCL5). These findings delineate the distinct yet overlapping roles of HMGB1 and pCTS-L in orchestrating immune responses, offering a foundation for targeted therapeutic development for inflammatory diseases.

Dysregulated inflammation, characterized by the uncontrolled release of inflammatory mediators, is central to the pathogenesis of numerous inflammatory diseases, including acute sepsis and chronic rheumatoid arthritis (RA). Despite therapeutic advances in RA, limitations of current anti-inflammatory treatments—such as broad immunosuppression and partial efficacy—highlight an urgent need for novel interventions. This review critically examines the pathogenic roles of High Mobility Group Box 1 (HMGB1) and procathepsin-L (pCTS-L) in dysregulated inflammation, mediated by their interactions with Toll-like receptor 4 (TLR4) and the Receptor for Advanced Glycation End Products (RAGE). Crucially, we highlight the newly established HMGB1-pCTS-L axis, in which HMGB1 directly upregulates pCTS-L expression and release. This axis initiates a delayed yet sustained inflammatory loop, which may predominantly activate the more enduring non-canonical NF-κB pathway. Furthermore, we explore the intricate role of tetranectin (TN), an endogenous HMGB1-binding protein, which inhibits HMGB1 release but paradoxically facilitates HMGB1-induced pyroptosis. Leveraging this complexity, we introduce the TN-derived P2–1 peptide as a highly specific inhibitor of the HMGB1-pCTS-L axis. This peptide binds HMGB1 to prevent its RAGE engagement and subsequent macrophage pyroptosis, without broadly suppressing initial inflammatory cascades. It also specifically inhibits HMGB1-induced pCTS-L expression and release, ameliorating both sepsis and RA even with delayed treatment. Its “disease-triggered” mechanism, selectively targeting extracellular HMGB1 only at pathological sites, promises enhanced safety and precision. This review positions the HMGB1-pCTS-L axis as a critical and therapeutically tractable pathway, with HMGB1- and pCTS-L-inhibiting antibodies and mimetic peptides representing promising next-generation interventions for a spectrum of inflammatory diseases.

A 110-amino acid precursor of dermcidin (pre-dermcidin, pre-DCD) with a 19-residue N-terminal leader signal sequence can be secreted by human eccrine sweat glands as a leader-less pro-domain-containing peptide (pro-DCD), which is enzymatically cleaved to generate C-terminal anti-microbial peptides (dermcidin-1, DCD-1) capable of killing various bacteria. Previously, it was unknown whether pro-DCD could be pharmacologically developed as potential therapeutics for lethal sepsis. Here, we demonstrated that pharmacological suppression of pro-DCD with polyclonal antibodies worsened sepsis-induced inflammation and liver injury, whereas supplementation of pro-DCD or its PEGylation derivatives significantly protected against sepsis, even when given 2–24 h after disease onset. These protective effects were associated with a significant reduction in circulating levels of surrogate biomarkers [e.g., Granulocyte Colony Stimulating Factor (G-CSF), Interleukin-6 (IL-6), keratinocytes-derived chemokine (KC), Monocyte Chemoattractant Protein 1 (MCP-1), Macrophage Inflammatory Protein-2 (MIP-2), and Soluble Tumor Necrosis Factor Receptor I (sTNFRI)], tissue injury, and blood bacterial counts. Although pro-DCD or its PEGylation derivatives failed to directly kill bacteria across a wide range of concentrations, they were able to activate microtubule-associated protein 1A/1B-light chain 3 (LC3), a marker of autophagy and phagosome maturation in LC3-associated bacterial phagocytosis. Our findings suggest that pro-DCD-derived agents hold promise as potential therapies for clinical sepsis.

Human dermcidin (DCD) is synthesized as a 110-amino acid precursor (pre-dermcidin, pre-DCD) containing a 19-residue leader signal sequence, which is removed to produce a leader-less pro-domain-containing peptide termed as pro-dermcidin, pro-DCD. Pro-DCD can be secreted by human eccrine sweat glands and then cleaved into antimicrobial peptides, such as dermcidin (DCD). Emerging evidence suggests that pro-DCD has broader physiological roles beyond antimicrobial defense, potentially serving as a therapeutic agent for inflammatory diseases like sepsis. In this review, we summarize recent evidence supporting pro-DCD as a regulator of innate immunity in sepsis.

Sepsis is a life-threatening organ dysfunction resulting from a dysregulated host response to infections that is initiated by the body’s innate immune system. Nearly a decade ago, we discovered that bacterial lipopolysaccharide (LPS) and serum amyloid A (SAA) upregulated Connexin 43 (Cx43) and Pannexin 1 (Panx1) hemichannels in macrophages. When overexpressed, these hemichannels contribute to sepsis pathogenesis by promoting ATP efflux, which intensifies the double-stranded RNA-activated protein kinase R (PKR)-dependent inflammasome activation, pyroptosis, and the release of pathogenic damage-associated molecular pattern (DAMP) molecules, such as HMGB1. Mimetic peptides targeting specific regions of Cx43 and Panx1 can distinctly modulate hemichannel activity in vitro, and diversely impact sepsis-induced lethality in vivo. Along with extensive supporting evidence from others, we now propose that hemichannel molecules play critical roles as endogenous regulators of innate immunity in sepsis.

The pathogenic mechanisms of bacterial infections and resultant sepsis are partly attributed to dysregulated inflammatory responses sustained by some late-acting mediators including the procathepsin-L (pCTS-L). It was entirely unknown whether any compounds of the U.S. Drug Collection could suppress pCTS-L-induced inflammation, and pharmacologically be exploited into possible therapies. Here, we demonstrated that a macrophage cell-based screening of a U.S. Drug Collection of 1360 compounds resulted in the identification of progesterone (PRO) as an inhibitor of pCTS-L-mediated production of several chemokines [e.g., Epithelial Neutrophil-Activating Peptide (ENA-78), Monocyte Chemoattractant Protein-1 (MCP-1) or MCP-3] and cytokines [e.g., Interleukin-10 (IL-10) or Tumor Necrosis Factor (TNF)] in primary human peripheral blood mononuclear cells (PBMCs). In vivo, these PRO-entrapping 2,6-dimethal-β-cyclodextrin (DM-β-CD) nanoparticles (containing 1.35 mg/kg PRO and 14.65 mg/kg DM-β-CD) significantly increased animal survival in both male (from 30% to 70%, n = 20, P = 0.041) and female (from 50% to 80%, n = 30, P = 0.026) mice even when they were initially administered at 24 h post the onset of sepsis. This protective effect was associated with a reduction of sepsis-triggered accumulation of three surrogate biomarkers [e.g., Granulocyte Colony Stimulating Factor (G-CSF) by 40%; Macrophage Inflammatory Protein-2 (MIP-2) by 45%; and Soluble Tumor Necrosis Factor Receptor I (sTNFRI) by 80%]. Surface Plasmon Resonance (SPR) analysis revealed a strong interaction between PRO and pCTS-L (KD = 78.2 ± 33.7 nM), which was paralleled with a positive correlation between serum PRO concentration and serum pCTS-L level (ρ = 0.56, P = 0.0009) or disease severity (Sequential Organ Failure Assessment, SOFA; ρ = 0.64, P = 0.0001) score in septic patients. Our observations support a promising opportunity to explore DM-β-CD nanoparticles entrapping lipophilic drugs as possible therapies for clinical sepsis.

Inflamm-aging is a condition of low-grade and chronic systemic inflammation characterized by a systemic increase in multiple inflammatory biomarkers such as tumor necrosis factor (TNF), interleukin 6 (IL-6), C-reactive protein (CRP), and CXCL9 (MIG) in experimental and clinical settings. However, despite the recent identification of extracellular procathepsin L (pCTS-L) as a novel mediator of inflammatory diseases such as sepsis, its possible role in inflamm-aging was previously not investigated. In the present study, we compared blood levels of pCTS-L and other 62 cytokines and chemokines between young and aged Balb/C mice by Western blotting and Cytokine Antibody Arrays. In light of the surprising finding of a marked increase in blood pCTS-L levels in aged mice, we propose that blood pCTS-L levels may serve as another biomarker of inflamm-aging. Given the capacity of pCTS-L in inducing various cytokines (e.g., TNF and IL-6), it will be important to test the hypothetic role of pCTS-L in inflamm-aging under experimental and clinical conditions.

Antibody-based strategies have been attempted to antagonize early cytokines of sepsis, but not yet been tried to target inducible late-acting mediators. Here, we report that the expression and secretion of procathepsin-L (pCTS-L) was induced by serum amyloid A (SAA) in innate immune cells, contributing to its late and systemic accumulation in experimental and clinical sepsis. Recombinant pCTS-L induced interleukin-6 (IL-6), IL-8, GRO-α/KC, GRO-β/MIP-2, and MCP-1 release in innate immune cells and moderately correlated with blood concentrations of these cytokines/chemokines in clinical sepsis. Mechanistically, pCTS-L interacted with Toll-like receptor 4 (TLR4) and the receptor for advanced glycation end products (RAGE) to induce cytokines/chemokines. Pharmacological suppression of pCTS-L with neutralizing polyclonal and monoclonal antibodies attenuated pCTS-L–mediated inflammation by impairing its interaction with TLR4 and RAGE receptors, and consequently rescued animals from lethal sepsis. Our findings have suggested a possibility of developing antibody strategies to prevent dysregulated immune responses mediated by late-acting cytokines.

INTRODUCTION:Microbial infections and resultant sepsis are leading causes of death in hospitals, representing approximately 20% of total deaths worldwide. Despite the difficulties in translating experimental insights into effective therapies for often heterogenous patient populations, an improved understanding of the pathogenic mechanisms underlying experimental sepsis is still urgently needed. Sepsis is partly attributable to dysregulated innate immune responses manifested by hyperinflammation and immunosuppression at different stages of microbial infections. AREAS COVERED:Here we review our recent progress in searching for late-acting mediators of experimental sepsis and propose high mobility group box 1 (HMGB1) and procathepsin-L (pCTS-L) as potential therapeutic targets for improving outcomes of lethal sepsis and other infectious diseases. EXPERT OPINION:It will be important to evaluate the efficacy of HMGB1- or pCTS-L-targeting agents for the clinical management of human sepsis and other infectious diseases in future studies.

The pathogenesis of microbial infections and sepsis is partly attributable to dysregulated innate immune responses propagated by late-acting proinflammatory mediators such as procathepsin L (pCTS-L). It was previously not known whether any natural product could inhibit pCTS-L-mediated inflammation or could be strategically developed into a potential sepsis therapy. Here, we report that systemic screening of a NatProduct Collection of 800 natural products led to the identification of a lipophilic sterol, lanosterol (LAN), as a selective inhibitor of pCTS-L-induced production of cytokines [e.g., Tumor Necrosis Factor (TNF) and Interleukin-6 (IL-6)] and chemokines [e.g., Monocyte Chemoattractant Protein-1 (MCP-1) and Epithelial Neutrophil-Activating Peptide (ENA-78)] in innate immune cells. To improve its bioavailability, we generated LAN-carrying liposome nanoparticles and found that these LAN-containing liposomes (LAN-L) similarly inhibited pCTS-L-induced production of several chemokines [e.g., MCP-1, Regulated upon Activation, Normal T Cell Expressed and Presumably Secreted (RANTES) and Macrophage Inflammatory Protein-2 (MIP-2)] in human blood mononuclear cells (PBMCs). In vivo, these LAN-carrying liposomes effectively rescued mice from lethal sepsis even when the first dose was given at 24 h post the onset of this disease. This protection was associated with a significant attenuation of sepsis-induced tissue injury and systemic accumulation of serval surrogate biomarkers [e.g., IL-6, Keratinocyte-derived Chemokine (KC), and Soluble Tumor Necrosis Factor Receptor I (sTNFRI)]. These findings support an exciting possibility to develop liposome nanoparticles carrying anti-inflammatory sterols as potential therapies for human sepsis and other inflammatory diseases.

Algal blooms and untreated wastewater will destroy the environment and ecosystem on which human beings depend. In this study, Solieria tenuis, a potential bloom in some regions of the sea in China, was used to mediate the composite of phycoerythrin (PE) and gold nanoparticles namely Au@PE NPs via a quick, easy, and effective manner. The physicochemical properties of Au@PE NPs were determined through UV-vis spectroscopy (UV-Vis), fluorescence spectroscopy (FP), fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The composite materials with a fine morphology and size (average size of 16 nm) exhibited superior catalytic abilities for the conversion of 4-nitrophenol(4-NP) to 4-aminophenol (4-AP, k298K 1/4 0.36 x 10-2 s) and the degradation of cationic dyes methylene blue (MB) and safranine O (SO) in wastewater. Additionally, the mechanisms of 4-NP's catalytic reduction and decolorization of dyes by Au@PE NPs were proposed. The results indicated that PE could not only act as capping and reducing agents but also enhance solubility and photocatalytic activity of the synthesized gold nanoparticles. The current study provides clear evidence of a potential economic solution for utilizing organisms that are harmful to the environment to develop novel bioconjugated composites with multiple functions for efficient pollutant removal and environmental remediation.& COPY; 2023 Published by Elsevier Ltd.

Glycyrrhizic acid and its primary metabolite glycyrrhetinic acid, are the main active ingredients in the licorice roots (glycyrrhiza species), which are widely used in several countries of the world, especially in east asian countries (China, Japan). These ingredients and their derivatives play an important role in treating many diseases, especially infectious diseases such as COVID-19 and hepatic infections. This review aims to summarize the different ways of synthesising the amide derivatives of glycyrrhizic acid and the main ways to synthesize the glycyrrhitinic acid derivatives. Also, to determine the main biological and pharmacological activity for these compounds from the previous studies to provide essential data to researchers for future studies.

Background Hepatic ischemia and reperfusion (I/R) injury is commonly associated with surgical liver resection or transplantation, and represents a major cause of liver damage and graft failure. Currently, there are no effective therapies to prevent hepatic I/R injury other than ischemic preconditioning and some preventative strategies. Previously, we have revealed the anti-inflammatory activity of a sweat gland-derived peptide, dermcidin (DCD), in macrophage/monocyte cultures. Here, we sought to explore its therapeutic potential and protective mechanisms in a murine model of hepatic I/R. Methods Male C57BL/6 mice were subjected to hepatic ischemia by clamping the hepatic artery and portal vein for 60 min, which was then removed to initiate reperfusion. At the beginning of reperfusion, 0.2 ml saline control or solution of DCD (0.5 mg/kg BW) or DCD-C34S analog (0.25 or 0.5 mg/kg BW) containing a Cys (C)→Ser (S) substitution at residue 34 was injected via the internal jugular vein. For survival experiments, mice were subjected to additional resection to remove non-ischemic liver lobes, and animal survival was monitored for 10 days. For mechanistic studies, blood and tissue samples were collected at 24 h after the onset of reperfusion, and subjected to measurements of various markers of inflammation and tissue injury by real-time RT-PCR, immunoassays, and histological analysis. Results Recombinant DCD or DCD-C34S analog conferred a significant protection against lethal hepatic I/R when given intravenously at the beginning of reperfusion. This protection was associated with a significant reduction in hepatic injury, neutrophilic CXC chemokine (Mip-2) expression, neutrophil infiltration, and associated inflammation. Furthermore, the administration of DCD also resulted in a significant attenuation of remote lung inflammatory injury. Mechanistically, DCD interacted with epidermal growth factor receptor (EGFR), a key regulator of liver inflammation, and significantly inhibited hepatic I/R-induced phosphorylation of EGFR as well as a downstream signaling molecule, protein kinase B (AKT). The suppression of EGFR expression by transducing Egfr-specific shRNA plasmid into macrophages abrogated the DCD-mediated inhibition of nitric oxide (NO) production induced by a damage-associated molecular pattern (DAMP), cold-inducible RNA-binding protein, CIRP. Conclusions The present study suggests that human DCD and its analog may be developed as novel therapeutics to attenuate hepatic I/R-induced inflammatory injury possibly by impairing EGFR signaling.

Sepsis remains a common cause of death in intensive care units, accounting for approximately 20% of total deaths worldwide. Its pathogenesis is partly attributable to dysregulated inflammatory responses to bacterial endotoxins (such as lipopolysaccharide, LPS), which stimulate innate immune cells to sequentially release early cytokines (such as tumor necrosis factor (TNF) and interferons (IFNs)) and late mediators (such as high-mobility group box 1, HMGB1). Despite difficulties in translating mechanistic insights into effective therapies, an improved understanding of the complex mechanisms underlying the pathogenesis of sepsis is still urgently needed. Here, we review recent progress in elucidating the intricate mechanisms underlying the regulation of HMGB1 release and action, and propose a few potential therapeutic candidates for future clinical investigations.

The India‐Asia collision has been the object of vigorous debate for decades, with ages of the start ranging from Late Cretaceous to Oligocene. Sedimentary records preserved in both near‐field and far‐field settings provide critical evidence concerning the age and mechanism of the collision. Gonjo Basin, one of a series of fault‐controlled basins developed along the eastern margin of Tibetan Plateau, contains well‐exposed sedimentary successions, providing great potential for understanding depositional, tectonic‐geomorphological and climatic history associated with India‐Asia collision and plateau uplift. Lithofacies analysis reveals that the sequences consist of sandstone, mudstone and conglomerate, formed in fluvial‐lacustrine systems. High‐resolution magnetostratigraphy, constrained by U‐Pb dating of zircon from a volcaniclastic layer which has been found in the central Gonjo Basin for the first time, indicates that sedimentation started at 69 Ma and continued in this locality until 50 Ma. Anisotropy of magnetic susceptibility (AMS) interpretation based on the age framework reveals a post‐depositional compression after 50 Ma, responding simultaneously to the early uplift of southeast Tibetan Plateau driven by India‐Asia collision.

For the clinical management of sepsis, antibody-based strategies have only been attempted to antagonize proinflammatory cytokines but not yet been tried to target harmless proteins that may interact with these pathogenic mediators. Here, we report an antibody strategy to intervene in the harmful interaction between tetranectin (TN) and a late-acting sepsis mediator, high-mobility group box 1 (HMGB1), in preclinical settings. We found that TN could bind HMGB1 to reciprocally enhance their endocytosis, thereby inducing macrophage pyroptosis and consequent release of lactate dehydrogenase and apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain. The genetic depletion of TN expression or supplementation of exogenous TN protein at subphysiological doses distinctly affected the outcomes of potentially lethal sepsis, revealing a previously underappreciated beneficial role of TN in sepsis. Furthermore, the administration of domain-specific polyclonal and monoclonal antibodies effectively inhibited TN/HMGB1 interaction and endocytosis and attenuated the sepsis-induced TN depletion and tissue injury, thereby rescuing animals from lethal sepsis. Our findings point to a possibility of developing antibody strategies to prevent harmful interactions between harmless proteins and pathogenic mediators of human diseases.

A severe acute respiratory syndrome (SARS)-like coronavirus 2 (SARS-CoV-2) has recently caused a pandemic COVID-19 disease that infected approximately 94 million and killed more than 2,000,000 people worldwide. Like the SARS-CoV, SARS-CoV-2 also employs a receptor-binding motif (RBM) of its envelope spike protein for binding the host angiotensin-converting enzyme 2 (ACE2) to gain viral entry. Currently, extensive efforts are being made to produce vaccines against a surface fragment of a SARS-CoV-2, such as the spike protein, in order to boost protective antibodies that can inhibit virus-ACE2 interaction to prevent viral entry. It was previously unknown how spike protein-targeting antibodies would affect innate inflammatory responses to SARS-CoV-2 infections. Here we generated a highly purified recombinant protein corresponding to the RBM of SARS-CoV-2, and used it to screen for cross-reactive monoclonal antibodies (mAbs). We found two RBM-binding mAbs that competitively inhibited its interaction with human ACE2, and specifically blocked the RBM-induced GM-CSF secretion in both human peripheral blood mononuclear cells and murine macrophage cultures. Our findings have suggested a possible strategy to prevent SARS-CoV-2-elicited “cytokine storm,” and revealed a potentially anti-inflammatory and protective mechanism for SARS-CoV-2 spike-based vaccines.