Javier Garcia-Pardo

Aging is associated with a progressive loss of proteostasis and increased susceptibility to neurodegenerative and metabolic disorders. Among the molecular mechanisms implicated in these processes, protein persulfidation, a hydrogen sulfide (H₂S)-mediated cysteine modification, has emerged as a critical regulator of protein function and redox homeostasis. Recent studies demonstrate that aging is accompanied by a decline in persulfidation and a concomitant increase in irreversible cysteine hyperoxidation, leading to protein dysfunction and aggregation. Beyond its established role in protecting proteins from oxidative damage, persulfidation has recently been shown to regulate biomolecular condensation and liquid–liquid phase separation, suppressing the formation of pathological protein assemblies linked to aging and neurodegenerative diseases. Moreover, pharmacological approaches that enhance persulfidation, including stimulation of endogenous H₂S production and treatment with ergothioneine, improve metabolic resilience, increase NAD⁺ levels, and promote healthspan in experimental models. In this review, we discuss emerging evidence linking loss of persulfidation to protein aggregation, biomolecular condensates, and age-related functional decline, and highlight therapeutic strategies aimed at restoring persulfidation as a promising avenue for healthy aging and disease intervention.

Cell division is a central process in all living organisms and requires the coordinated action of many proteins and regulatory elements. In most bacteria, the division and cell wall (dcw) gene cluster is regulated by the first gene of the dcw operon, mraZ, a highly conserved DNA-binding transcriptional regulator. Here we report the structural basis of MraZ transcriptional regulation by the resolution of three different cryo-EM structures of MraZ in complex with the upstream promoter region of the dcw cluster from Mycoplasma genitalium at 3.36, 3.57 and 3.87 Å resolution. The structures reveal the specific interactions between MraZ DNA-binding motif and nucleobases of the binding boxes, which induces distortion in the MraZ octamer to enable the interaction with the four repetitive binding boxes of the promoter DNA. The “cradle-like” DNA-binding motif of MraZ exposes three highly conserved basic residues, Lys13, Arg15 and Arg86, which are essential for binding to the consensus sequence of its cognate promoter. Ultimately, the mechanism behind MraZ’s DNA binding and regulation of the dcw operon could be translated to other species, working as a general mechanism for the regulation of dcw gene cluster in bacteria.

The self-assembling nature of coiled-coils has brought this common structural motif into the spotlight of protein design since it offers a customizable framework for engineering innovative protein nanoparticles with tailored functionalities. We recently harnessed the self-assembling capabilities of ZapB, a bacterial coiled-coil protein, to build up fluorescent protein nanoparticles possessing remarkable affinity for antibodies. Here, we describe a complete workflow detailing the design, production, and characterization of such coiled-coil-based protein nanostructures. Additionally, we detail their functionalization with specific antibodies and illustrate their utility in stimulating the activation and proliferation of human T cells, underscoring the potential of these protein-only nanoparticles in immunotherapeutic interventions.

The coronavirus disease 2019 (COVID‐19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), continues to challenge global health despite widespread vaccination efforts, underscoring the need for innovative strategies to combat emerging infectious diseases effectively. Herein, LCB1‐NPs and LCB3‐NPs are engineered as a novel class of protein‐only nanoparticles formed through coiled coil‐driven self‐assembly and tailored to interact specifically with the SARS‐CoV‐2 spike protein. The multivalency of LCB1‐NPs and LCB3‐NPs offers a strategy for efficiently targeting and neutralizing SARS‐CoV‐2 both in solution and when immobilized on surfaces. It is demonstrated that LCB1‐NPs and LCB3‐NPs bind to the SARS‐CoV‐2 spike protein's receptor‐binding domain (RBD) with high affinity, effectively blocking the entry of SARS‐CoV‐2 virus‐like particles into angiotensin‐converting enzyme 2 (ACE2)‐coated human cells. The cost‐effectiveness, scalability, and straightforward production process of these protein nanoparticles make them suitable for developing novel anti‐viral materials. Accordingly, it is shown how these nanostructures can be packed into columns to build up economic and highly potent trapping devices for SARS‐CoV‐2 adsorption.

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Background The interleukin (IL)-1-family receptor antagonist IL-38 has emerged as a negative regulator of auto-inflammation. Given the intricate interplay between antitumor immunity and auto-inflammation, we hypothesized that blocking IL-38 may enhance tumor immune control. Methods Our hypothesis was tested in the transgenic polyoma virus middle T oncoprotein mammary carcinoma model that is suitable for identifying strong immunomodulators. To investigate the effect of acute IL-38 blockade, we used a neutralizing antibody, alone or in combination with chemotherapy. Immune cell composition and location in tumors were determined by flow cytometry and immunohistochemistry, respectively. The role of γδ T cells was studied using an antibody blocking γδ T-cell receptor signaling. Whole transcriptome RNA sequencing and RNA expression analysis were employed to determine mechanisms downstream of IL-38 neutralization. Additionally, in vitro assays with γδ T cells, CD8+ T cells and cDC1, followed by in vivo CD8+ T cell depletion, were performed to study the underlying mechanistic pathways. Results Both, genetic ablation of IL-38 and neutralization with the antibody, reduced tumorigenesis, and IL-38 blockade improved chemotherapy efficacy. This was accompanied by an augmented lymphocyte infiltrate dominated by γδ T cells and CD8+ T cells, and signaling through the γδ-T-cell receptor was required for CD8+ T cell infiltration. Rather than directly interacting with CD8+ T cells, γδ T cells recruited conventional dendritic cells (cDC1) into tumors via the chemokine Xcl1. cDC1 in turn activated CD8+ T cells via the Notch pathway. Moreover, IL-38 negatively correlated with cDC1, XCL1-producing γδ T cells, T-cell infiltrates and survival in patients with mammary carcinoma. Conclusions These data suggest that interfering with IL-38 improves antitumor immunity even in immunologically cold tumors.

Antimicrobial peptides (AMPs) are important mediator molecules of the innate defense mechanisms in a wide range of living organisms, including bacteria, mammals, and plants. Among them, peptide protease inhibitors (PPIs) from plants play a central role in their defense mechanisms by directly attacking pathogens or by modulating the plant’s defense response. The growing prevalence of microbial resistance to currently available antibiotics has intensified the interest concerning these molecules as novel antimicrobial agents. In this scenario, PPIs isolated from a variety of plants have shown potential in inhibiting the growth of pathogenic bacteria, protozoans, and fungal strains, either by interfering with essential biochemical or physiological processes or by altering the permeability of biological membranes of invading organisms. Moreover, these molecules are active inhibitors of a range of proteases, including aspartic, serine, and cysteine types, with some showing particular efficacy as trypsin and chymotrypsin inhibitors. In this review, we provide a comprehensive analysis of the potential of plant-derived PPIs as novel antimicrobial molecules, highlighting their broad-spectrum antimicrobial efficacy, specificity, and minimal toxicity. These natural compounds exhibit diverse mechanisms of action and often multifunctionality, positioning them as promising molecular scaffolds for developing new therapeutic antibacterial agents.

Amyloid fibrils are highly ordered supramolecular aggregates, where identical protein molecules stack in a fibrillar conformation. They typically exhibit a cross-ß fold, where ß-sheets are often tw...