Brianna Dalesandro

Cell Death Dis. 2024 May 2;15(5):311. doi: 10.1038/s41419-024-06668-9.

ABSTRACT

Cancer cells are highly dependent on bioenergetic processes to support their growth and survival. Disruption of metabolic pathways, particularly by targeting the mitochondrial electron transport chain complexes (ETC-I to V) has become an attractive therapeutic strategy. As a result, the search for clinically effective new respiratory chain inhibitors with minimized adverse effects is a major goal. Here, we characterize a new OXPHOS inhibitor compound called MS-L6, which behaves as an inhibitor of ETC-I, combining inhibition of NADH oxidation and uncoupling effect. MS-L6 is effective on both intact and sub-mitochondrial particles, indicating that its efficacy does not depend on its accumulation within the mitochondria. MS-L6 reduces ATP synthesis and induces a metabolic shift with increased glucose consumption and lactate production in cancer cell lines. MS-L6 either dose-dependently inhibits cell proliferation or induces cell death in a variety of cancer cell lines, including B-cell and T-cell lymphomas as well as pediatric sarcoma. Ectopic expression of Saccharomyces cerevisiae NADH dehydrogenase (NDI-1) partially restores the viability of B-lymphoma cells treated with MS-L6, demonstrating that the inhibition of NADH oxidation is functionally linked to its cytotoxic effect. Furthermore, MS-L6 administration induces robust inhibition of lymphoma tumor growth in two murine xenograft models without toxicity. Thus, our data present MS-L6 as an inhibitor of OXPHOS, with a dual mechanism of action on the respiratory chain and with potent antitumor properties in preclinical models, positioning it as the pioneering member of a promising drug class to be evaluated for cancer therapy. MS-L6 exerts dual mitochondrial effects: ETC-I inhibition and uncoupling of OXPHOS. In cancer cells, MS-L6 inhibited ETC-I at least 5 times more than in isolated rat hepatocytes. These mitochondrial effects lead to energy collapse in cancer cells, resulting in proliferation arrest and cell death. In contrast, hepatocytes which completely and rapidly inactivated this molecule, restored their energy status and survived exposure to MS-L6 without apparent toxicity.

PMID:38697987 | PMC:PMC11065874 | DOI:10.1038/s41419-024-06668-9

ACS Chem Biol. 2024 Apr 25. doi: 10.1021/acschembio.4c00092. Online ahead of print.

ABSTRACT

Targeted protein degradation is becoming more and more important in the field of drug development. Compared with proteasomal-based degraders, lysosomal-based degraders have a broader target spectrum of targets, which have been demonstrated to have great potential, especially in degrading undruggable proteins. Recently, we developed a programmable and facile screening PROTAC development platform based on peptide self-assembly termed split-and-mix PROTAC (SM-PROTAC). In this study, we applied this technology for the development of lysosome-based degraders, named a split-and-mix chaperone-mediated autophagy-based degrader (SM-CMAD). We successfully demonstrated SM-CMAD as a universal platform by degrading several targets, including ERα, AR, MEK1/2, and BCR-ABL. Different from other lysosomal-based degraders, SM-CMAD was capable of facile screening with programmable ligand ratios. We believe that our work will promote the development of other multifunctional molecules and clinical translation for lysosomal-based degraders.

PMID:38662199 | DOI:10.1021/acschembio.4c00092

Nat Commun. 2024 Apr 22;15(1):3404. doi: 10.1038/s41467-024-47783-7.

ABSTRACT

DltB, a model member of the Membrane-Bound O-AcylTransferase (MBOAT) superfamily, plays a crucial role in D-alanylation of the lipoteichoic acid (LTA), a significant component of the cell wall of gram-positive bacteria. This process stabilizes the cell wall structure, influences bacterial virulence, and modulates the host immune response. Despite its significance, the role of DltB is not well understood. Through biochemical analysis and cryo-EM imaging, we discover that Streptococcus thermophilus DltB forms a homo-tetramer on the cell membrane. We further visualize DltB in an apo form, in complex with DltC, and in complex with its inhibitor amsacrine (m-AMSA). Each tetramer features a central hole. The C-tunnel of each protomer faces the intratetramer interface and provides access to the periphery membrane. Each protomer binds a DltC without changing the tetrameric organization. A phosphatidylglycerol (PG) molecule in the substrate-binding site may serve as an LTA carrier. The inhibitor m-AMSA bound to the L-tunnel of each protomer blocks the active site. The tetrameric organization of DltB provides a scaffold for catalyzing D-alanyl transfer and regulating the channel opening and closing. Our findings unveil DltB's dual function in the D-alanylation pathway, and provide insight for targeting DltB as a anti-virulence antibiotic.

PMID:38649359 | PMC:PMC11035591 | DOI:10.1038/s41467-024-47783-7

Biomed Chromatogr. 2024 Apr 15:e5866. doi: 10.1002/bmc.5866. Online ahead of print.

ABSTRACT

Immunoglobulin nephropathy (IgAN) stands as the most prevalent primary glomerular nephropathy globally, typically diagnosed through an invasive renal biopsy. Emerging research suggests the significant involvement of chiral amino acids in kidney disease progression. This study introduces a nonderivative LC-tandem mass spectrometry approach, offering efficient separation outcomes within 15 min for identifying chiral amino acids in human urine samples. Subsequently, using this method, the analysis of l- and d-amino acids in the urine of both patients with IgAN and healthy individuals was conducted. Fourteen d-amino acids and 20 l-amino acids were identified in the urine samples obtained from 17 patients with IgAN and 21 healthy individuals. The results indicated notable variances in the concentrations of both l- and d-amino acids between the IgAN and healthy control groups. In contrast to the healthy group, the IgAN group exhibited higher mean urine concentrations of most l-amino acids and lower concentrations of d-amino acids. Furthermore, correlations between amino acids and clinical markers were investigated. These results propose a novel method for monitoring trace amino acids in urine samples and introduce a new concept for potential markers of IgAN.

PMID:38618866 | DOI:10.1002/bmc.5866

Nat Commun. 2024 Apr 24;15(1):3420. doi: 10.1038/s41467-024-47457-4.

ABSTRACT

Poly-β-(1-6)-N-acetylglucosamine (PNAG) is an important vaccine target, expressed on many pathogens. A critical hurdle in developing PNAG based vaccine is that the impacts of the number and the position of free amine vs N-acetylation on its antigenicity are not well understood. In this work, a divergent strategy is developed to synthesize a comprehensive library of 32 PNAG pentasaccharides. This library enables the identification of PNAG sequences with specific patterns of free amines as epitopes for vaccines against Staphylococcus aureus (S. aureus), an important human pathogen. Active vaccination with the conjugate of discovered PNAG epitope with mutant bacteriophage Qβ as a vaccine carrier as well as passive vaccination with diluted rabbit antisera provides mice with near complete protection against infections by S. aureus including methicillin-resistant S. aureus (MRSA). Thus, the comprehensive PNAG pentasaccharide library is an exciting tool to empower the design of next generation vaccines.

PMID:38658531 | PMC:PMC11043332 | DOI:10.1038/s41467-024-47457-4

Arch Virol. 2024 Apr 29;169(5):112. doi: 10.1007/s00705-024-06024-4.

ABSTRACT

Previously, we reported a neutralizing monoclonal antibody, A8A11, raised against a novel conserved epitope within the hepatitis C virus (HCV) E2 protein, that could significantly reduce HCV replication. Here, we report the nucleotide sequence of A8A11 and demonstrate the efficacy of a single-chain variable fragment (scFv) protein that mimics the antibody, inhibits the binding of an HCV virus-like particle to hepatocytes, and reduces viral RNA replication in a cell culture system. More importantly, scFv A8A11 was found to effectively restrict the increase of viral RNA levels in the serum of HCV-infected chimeric mice harbouring human hepatocytes. These results suggest a promising approach to neutralizing-antibody-based therapeutic interventions against HCV infection.

PMID:38683226 | DOI:10.1007/s00705-024-06024-4

Elife. 2024 Apr 30;12:RP89098. doi: 10.7554/eLife.89098.

ABSTRACT

The agr quorum-sensing system links Staphylococcus aureus metabolism to virulence, in part by increasing bacterial survival during exposure to lethal concentrations of H₂O₂, a crucial host defense against S. aureus. We now report that protection by agr surprisingly extends beyond post-exponential growth to the exit from stationary phase when the agr system is no longer turned on. Thus, agr can be considered a constitutive protective factor. Deletion of agr resulted in decreased ATP levels and growth, despite increased rates of respiration or fermentation at appropriate oxygen tensions, suggesting that Δagr cells undergo a shift towards a hyperactive metabolic state in response to diminished metabolic efficiency. As expected from increased respiratory gene expression, reactive oxygen species (ROS) accumulated more in the agr mutant than in wild-type cells, thereby explaining elevated susceptibility of Δagr strains to lethal H₂O₂ doses. Increased survival of wild-type agr cells during H₂O₂ exposure required sodA, which detoxifies superoxide. Additionally, pretreatment of S. aureus with respiration-reducing menadione protected Δagr cells from killing by H₂O₂. Thus, genetic deletion and pharmacologic experiments indicate that agr helps control endogenous ROS, thereby providing resilience against exogenous ROS. The long-lived 'memory' of agr-mediated protection, which is uncoupled from agr activation kinetics, increased hematogenous dissemination to certain tissues during sepsis in ROS-producing, wild-type mice but not ROS-deficient (Cybb^-/-) mice. These results demonstrate the importance of protection that anticipates impending ROS-mediated immune attack. The ubiquity of quorum sensing suggests that it protects many bacterial species from oxidative damage.

PMID:38687677 | PMC:PMC11060713 | DOI:10.7554/eLife.89098

Front Immunol. 2024 Apr 11;15:1337973. doi: 10.3389/fimmu.2024.1337973. eCollection 2024.

ABSTRACT

Cytotoxic T lymphocytes are the primary effector immune cells responsible for protection against cancer, as they target peptide neoantigens presented through the major histocompatibility complex (MHC) on cancer cells, leading to cell death. Targeting peptide-MHC (pMHC) complex offers a promising strategy for immunotherapy due to their specificity and effectiveness against cancer. In this work, we exploit the acidic tumor micro-environment to selectively deliver antigenic peptides to cancer using pH(low) insertion peptides (pHLIP). We demonstrated the delivery of MHC binding peptides directly to the cytoplasm of melanoma cells resulted in the presentation of antigenic peptides on MHC, and activation of T cells. This work highlights the potential of pHLIP as a vehicle for the targeted delivery of antigenic peptides and its presentation via MHC-bound complexes on cancer cell surface for activation of T cells with implications for enhancing anti-cancer immunotherapy.

PMID:38665920 | PMC:PMC11043575 | DOI:10.3389/fimmu.2024.1337973

Int J Mol Sci. 2024 Mar 25;25(7):3638. doi: 10.3390/ijms25073638.

ABSTRACT

Enterotoxigenic Escherichia coli (ETEC) strains are significant contributors to postweaning diarrhea in piglets. Of the ETEC causing diarrhea, K88 and F18 accounted for 92.7%. Despite the prevalence of ETEC K88 and F18, there is currently no effective vaccine available due to the diversity of these strains. This study presents an innovative approach by isolating chicken-derived single-chain variable fragment antibodies (scFvs) specific to K88 and F18 fimbrial antigens from chickens immunized against these ETEC virulence factors. These scFvs effectively inhibited adhesion of K88 and F18 to porcine intestinal epithelial cells (IPEC-J2), with the inhibitory effect demonstrating a dose-dependent increase. Furthermore, a bispecific scFv was designed and expressed in Pichia pastoris. This engineered construct displayed remarkable potency; at a concentration of 25.08 μg, it significantly reduced the adhesion rate of ETEC strains to IPEC-J2 cells by 72.10% and 69.11% when challenged with either K88 or F18 alone. Even in the presence of both antigens, the adhesion rate was notably decreased by 57.92%. By targeting and impeding the initial adhesion step of ETEC pathogenesis, this antibody-based intervention holds promise as a potential alternative to antibiotics, thereby mitigating the risks associated with antibiotic resistance and residual drug contamination in livestock production. Overall, this study lays the groundwork for the development of innovative treatments against ETEC infections in piglets.

PMID:38612450 | PMC:PMC11011568 | DOI:10.3390/ijms25073638

Front Immunol. 2024 Apr 4;15:1392546. doi: 10.3389/fimmu.2024.1392546. eCollection 2024.

ABSTRACT

Immunotherapy has been developed, which harnesses and enhances the innate powers of the immune system to fight disease, particularly cancer. PD-1 (programmed death-1) and PD-L1 (programmed death ligand-1) are key components in the regulation of the immune system, particularly in the context of cancer immunotherapy. PD-1 and PD-L1 are regulated by PTMs, including phosphorylation, ubiquitination, deubiquitination, acetylation, palmitoylation and glycosylation. PROTACs (Proteolysis Targeting Chimeras) are a type of new drug design technology. They are specifically engineered molecules that target specific proteins within a cell for degradation. PROTACs have been designed and demonstrated their inhibitory activity against the PD-1/PD-L1 pathway, and showed their ability to degrade PD-1/PD-L1 proteins. In this review, we describe how PROTACs target PD-1 and PD-L1 proteins to improve the efficacy of immunotherapy. PROTACs could be a novel strategy to combine with radiotherapy, chemotherapy and immunotherapy for cancer patients.

PMID:38638430 | PMC:PMC11024247 | DOI:10.3389/fimmu.2024.1392546

Adv Sci (Weinh). 2024 Apr 11:e2307963. doi: 10.1002/advs.202307963. Online ahead of print.

ABSTRACT

In recent decades, the role of tumor biomechanics on cancer cell behavior at the primary site has been increasingly appreciated. However, the effect of primary tumor biomechanics on the latter stages of the metastatic cascade, such as metastatic seeding of secondary sites and outgrowth remains underappreciated. This work sought to address this in the context of triple negative breast cancer (TNBC), a cancer type known to aggressively disseminate at all stages of disease progression. Using mechanically tuneable model systems, mimicking the range of stiffness's typically found within breast tumors, it is found that, contrary to expectations, cancer cells exposed to softer microenvironments are more able to colonize secondary tissues. It is shown that heightened cell survival is driven by enhanced metabolism of fatty acids within TNBC cells exposed to softer microenvironments. It is demonstrated that uncoupling cellular mechanosensing through integrin β1 blocking antibody effectively causes stiff primed TNBC cells to behave like their soft counterparts, both in vitro and in vivo. This work is the first to show that softer tumor microenvironments may be contributing to changes in disease outcome by imprinting on TNBC cells a greater metabolic flexibility and conferring discrete cell survival advantages.

PMID:38602451 | DOI:10.1002/advs.202307963

Nat Commun. 2024 Apr 2;15(1):2835. doi: 10.1038/s41467-024-47359-5.

ABSTRACT

Obesity is a well-established risk factor for human cancer, yet the underlying mechanisms remain elusive. Immune dysfunction is commonly associated with obesity but whether compromised immune surveillance contributes to cancer susceptibility in individuals with obesity is unclear. Here we use a mouse model of diet-induced obesity to investigate tumor-infiltrating CD8 ⁺ T cell responses in lean, obese, and previously obese hosts that lost weight through either dietary restriction or treatment with semaglutide. While both strategies reduce body mass, only dietary intervention restores T cell function and improves responses to immunotherapy. In mice exposed to a chemical carcinogen, obesity-related immune dysfunction leads to higher incidence of sarcoma development. However, impaired immunoediting in the obese environment enhances tumor immunogenicity, making the malignancies highly sensitive to immunotherapy. These findings offer insight into the complex interplay between obesity, immunity and cancer, and provide explanation for the obesity paradox observed in clinical immunotherapy settings.

PMID:38565540 | PMC:PMC10987624 | DOI:10.1038/s41467-024-47359-5

BMC Infect Dis. 2024 Apr 2;24(1):371. doi: 10.1186/s12879-024-09262-8.

ABSTRACT

BACKGROUND: There is an urgent clinical need for developing novel immunoprophylaxis and immunotherapy strategies against Staphylococcus aureus (S. aureus). In our previous work, immunization with a tetra-branched multiple antigenic peptide, named MAP2-3 that mimics lipoteichoic acid, a cell wall component of S. aureus, successfully induced a humoral immune response and protected BALB/c mice against S. aureus systemic infection. In this study, we further investigated whether vaccination with MAP2-3 can elicit immunologic memory.

METHODS: BALB/c mice were immunized with MAP2-3 five times. After one month of the last vaccination, mice were challenged with heat-killed S. aureus via intraperitoneal injection. After a 7-day inoculation, the percentage of plasma cells, memory B cells, effector memory T cells, and follicular helper T cells were detected by flow cytometry. The levels of IL-6, IL-21, IL-2, and IFN-γ were measured by real-time PCR and ELISA. Flow cytometry results were compared by using one-way ANOVA or Mann-Whitney test, real-time PCR results were compared by using one-way ANOVA, and ELISA results were compared by using one-way ANOVA or student's t-test.

RESULTS: The percentage of plasma cells and memory B cells in the spleen and bone marrow from the MAP2-3 immunized mice was significantly higher than that from the control mice. The percentage of effector memory T cells in spleens and lymphoid nodes as well as follicular helper T cells in spleens from the MAP2-3 immunized mice were also higher. Moreover, the levels of IL-6 and IL-21, two critical cytokines for the development of memory B cells, were significantly higher in the isolated splenocytes from immunized mice after lipoteichoic acid stimulation.

CONCLUSIONS: Immunization with MAP2-3 can efficiently induce memory B cells and memory T cells.

PMID:38566017 | PMC:PMC10986077 | DOI:10.1186/s12879-024-09262-8

bioRxiv [Preprint]. 2024 Mar 14:2024.03.14.584917. doi: 10.1101/2024.03.14.584917.

ABSTRACT

Clostridioides difficile, the leading cause of antibiotic-associated diarrhea, relies primarily on 3-3 crosslinks created by L,D-transpeptidases (LDTs) to fortify its peptidoglycan (PG) cell wall. This is unusual, as in most bacteria the vast majority of PG crosslinks are 4-3 crosslinks, which are created by penicillin-binding proteins (PBPs). Here we report the unprecedented observation that 3-3 crosslinking is essential for viability in C. difficile. We also report the discovery of a new family of LDTs that use a VanW domain to catalyze 3-3 crosslinking rather than a YkuD domain as in all previously known LDTs. Bioinformatic analyses indicate VanW domain LDTs are less common than YkuD domain LDTs and are largely restricted to Gram-positive bacteria. Our findings suggest that LDTs might be exploited as targets for antibiotics that kill C. difficile without disrupting the intestinal microbiota that is important for keeping C. difficile in check.

PMID:38559057 | PMC:PMC10980060 | DOI:10.1101/2024.03.14.584917

Carbohydr Polym. 2024 Jun 15;334:122031. doi: 10.1016/j.carbpol.2024.122031. Epub 2024 Mar 8.

ABSTRACT

The efficacy of cancer therapies is significantly compromised by the immunosuppressive tumor milieu. Herein, we introduce a previously unidentified therapeutic strategy that harnesses the synergistic potential of chitosan-coated bacterial vesicles and a targeted chemotherapeutic agent to activate dendritic cells, thereby reshaping the immunosuppressive milieu for enhanced cancer therapy. Our study focuses on the protein-mediated modification of bacterium-derived minicells with chitosan molecules, facilitating the precise delivery of Doxorubicin to tumor sites guided by folate-mediated homing cues. These engineered minicells demonstrate remarkable specificity in targeting lung carcinomas, triggering immunogenic cell death and releasing tumor antigens and damage-associated molecular patterns, including calreticulin and high mobility group box 1. Additionally, the chitosan coating, coupled with bacterial DNA from the minicells, initiates the generation of reactive oxygen species and mitochondrial DNA release. These orchestrated events culminate in dendritic cell maturation via activation of the stimulator of interferon genes signaling pathway, resulting in the recruitment of CD4⁺ and CD8⁺ cytotoxic T cells and the secretion of interferon-β, interferon-γ, and interleukin-12. Consequently, this integrated approach disrupts the immunosuppressive tumor microenvironment, impeding tumor progression. By leveraging bacterial vesicles as potent dendritic cell activators, our strategy presents a promising paradigm for synergistic cancer treatment, seamlessly integrating chemotherapy and immunotherapy.

PMID:38553230 | DOI:10.1016/j.carbpol.2024.122031

Diabetes Obes Metab. 2024 Mar 21. doi: 10.1111/dom.15524. Online ahead of print.

ABSTRACT

Despite its considerable and growing burden, there are currently no Food and Drug Administration-approved treatments for metabolic dysfunction-associated steatotic liver disease or its progressive form, metabolic dysfunction-associated steatohepatitis (MASH). Several glucagon-like peptide-1 receptor agonists (GLP-1RAs) and other agents are in various phases of clinical development for use in MASH; an ideal therapy should reduce liver fat content, improve chronic liver disease, help mitigate metabolic comorbidities and decrease all-cause mortality. Because of interconnected disease mechanisms, metabolic dysfunction-associated steatotic liver disease/MASH often coexists with type 2 diabetes (T2D), obesity and cardiovascular disease. Various GLP-1RAs are Food and Drug Administration-approved for use in T2D, and two, liraglutide and semaglutide, are approved for overweight and obesity. GLP-1RAs decrease glucose levels and body weight and improve cardiovascular outcomes in people with T2D who are at high risk of cardiovascular disease. In addition, GLP-1RAs have been reported to reduce liver fat content and liver enzymes, reduce oxidative stress and improve hepatic de novo lipogenesis and the histopathology of MASH. Weight loss may contribute to these effects; however, the exact mechanisms are unknown. Adverse events that are commonly associated with GLP-1RAs include vomiting, nausea and diarrhoea. There is a lack of evidence from meta-analyses regarding the increased risk of acute pancreatitis and various forms of cancer with GLP-1RAs. Large-scale, phase 3 trials, which will provide definitive data on GLP-1RAs and other potential therapies in MASH, are ongoing. Given the spectrum of modalities under investigation, it is hoped that these trials will support the identification of pharmacotherapies that provide clinical benefit for patients with MASH.

PMID:38511418 | DOI:10.1111/dom.15524

ACS Omega. 2024 Feb 29;9(10):11551-11561. doi: 10.1021/acsomega.3c08621. eCollection 2024 Mar 12.

ABSTRACT

Mitochondrial uncouplers are actively sought as potential therapeutics. Here, we report the first successful synthesis of mitochondria-targeted derivatives of the highly potent uncoupler 3,5-ditert-butyl-4-hydroxybenzylidene-malononitrile (SF6847), bearing a cationic alkyl(triphenyl)phosphonium (TPP) group. As a key step of the synthesis, we used condensation of a ketophenol with malononitrile via the Knoevenagel reaction. SF-C₅-TPP with a pentamethylene linker between SF6847 and TPP, stimulating respiration and collapsing membrane potential of rat liver mitochondria at submicromolar concentrations, proved to be the most effective uncoupler of the series. SF-C₅-TPP showed pronounced protonophoric activity on a model planar bilayer lipid membrane. Importantly, SF-C₅-TPP exhibited rather low toxicity in fibroblast cell culture, causing mitochondrial depolarization in cells at concentrations that only slightly affected cell viability. SF-C₅-TPP was more effective in decreasing the mitochondrial membrane potential in the cell culture than SF6847, in contrast to the case of isolated mitochondria. Like other zwitterionic uncouplers, SF-C₅-TPP inhibited the growth of Bacillus subtilis in the micromolar concentration range.

PMID:38496966 | PMC:PMC10938414 | DOI:10.1021/acsomega.3c08621

BMJ. 2024 Mar 13;384:q642. doi: 10.1136/bmj.q642.

NO ABSTRACT

PMID:38479760 | DOI:10.1136/bmj.q642

Nat Commun. 2024 Mar 7;15(1):2007. doi: 10.1038/s41467-024-46321-9.

ABSTRACT

Monoclonal IgG antibodies constitute the fastest growing class of therapeutics. Thus, there is an intense interest to design more potent antibody formats, where long plasma half-life is a commercially competitive differentiator affecting dosing, frequency of administration and thereby potentially patient compliance. Here, we report on an Fc-engineered variant with three amino acid substitutions Q311R/M428E/N434W (REW), that enhances plasma half-life and mucosal distribution, as well as allows for needle-free delivery across respiratory epithelial barriers in human FcRn transgenic mice. In addition, the Fc-engineered variant improves on-target complement-mediated killing of cancer cells as well as both gram-positive and gram-negative bacteria. Hence, this versatile Fc technology should be broadly applicable in antibody design aiming for long-acting prophylactic or therapeutic interventions.

PMID:38453922 | PMC:PMC10920689 | DOI:10.1038/s41467-024-46321-9