Unsynchronized butyrophilin molecules dictate cancer cell evasion of Vγ9Vδ2 T-cell killing

BTN3A2 interacted with MFGE8 to alleviate preeclampsia by promoting ferroptosis and inhibiting angiogenesis

AIMS

Preeclampsia (PE) is a major cause of maternal and perinatal morbidity and mortality and is characterized by placental ischemia. Angiogenic disorders and ferroptosis are key mechanisms in PE; however, their relationship remains unclear. The butyrophilin 3A (BTN3A) family member BTN3A2 is involved in the progression of many cancers; however, its role in PE angiogenesis and ferroptosis is unclear. In this study, we investigated the role of BTN3A2 in PE angiogenesis and ferroptosis.

MATERIALS AND METHODS

Placental tissues were collected from healthy individuals and PE patients to explore the correlation between ferroptosis and angiogenesis. Human umbilical vein endothelial cells (HUVECs) were subjected to hypoxia, ferrostatin-1, Erastin, and gene manipulations (oe-BTN3A2, si-BTN3A2, and si-milk factor-globule-EFG factor 8 (MFGE8)) to elucidate the underlying mechanisms. Finally, a rat model of PE was established by intraperitoneal injection of Nomega-nitro-L-arginine methyl ester to verify the effects of BTN3A2 on angiogenesis.

KEY FINDINGS

Placental ferroptosis was negatively correlated with angiogenesis in PE. Clone number, migration, and tube number decreased in HUVECs after hypoxic exposure, and these effects were reversed by ferrostatin-1. BTN3A2 was increased in PE placentae and inhibited the viability of hypoxic HUVECs by inducing ferroptosis. Mechanistically, BTN3A2 interacted with MFGE8, and BTN3A2 promoted hypoxia-induced ferroptosis in HUVECs by downregulating MFGE8. Additionally, BTN3A2 knockdown promoted placental angiogenesis and improved the prognosis in PE rats.

SIGNIFICANCE

BTN3A2 interacted with MFGE8 to alleviate PE by promoting ferroptosis and inhibiting angiogenesis. Therefore, it may serve as a potential therapeutic target for the diagnosis and treatment of PE.

Deciphering Glutaminyl Cyclase Catalytic Pathways Enables Recognition of Anchor Pharmacophores for Inhibitor Discovery

Glutaminyl cyclases are responsible for N-terminal pyroglutamate modifications of various protein/peptide substrates, influencing their metabolic stability or biological functions. However, the precise chemical pathways by which glutaminyl cyclases catalyze the conversion of N-terminal glutamine/glutamate to pyroglutamate are not yet fully understood. We initially identified the catalytically essential components by cross-species structural analysis, followed by ab initio quantum mechanics/molecular mechanics (QM/MM) calculations of human secretory glutaminyl cyclase (sQC) with two tripeptide substrates, QFA and EFA. The results revealed that sQC processes similar reaction pathways for QFA and EFA, but with distinctly different reaction energy barriers. In both reaction pathways, the catalytic triad E201 directly mediates multiple proton transfers, while D248 and D305 primarily maintain the orientation of the triad and stabilize substrate binding. Based on the anchor pharmacophores recognized by the analysis of sQC catalytic intermediates, we successfully identified the imidazole-sulfonamide inhibitors that mimic substrate binding, as validated by cocrystallographic analysis.

Plasma proteomics identifies proteins and pathways associated with incident depression in 46,165 adults

Proteomic alterations preceding the onset of depression offer valuable insights into its development and potential interventions. Leveraging data from 46,165 UK Biobank participants and 2920 plasma proteins profiled at baseline, we conducted a longitudinal analysis with a median follow-up of 14.5 years to explore the relationship between plasma proteins and incident depression. Linear regression was then used to assess associations between depression-related proteins and brain structures, genetic factors, and stress-related events. Our analysis identified 157 proteins associated with incident depression (P <1.71 × 10-5), including novel associations with proteins such as GAST, PLAUR, LRRN1, BCAN, and ITGA11. Notably, higher expression levels of GDF15 (P = 6.18 × 10-26) and PLAUR (P = 2.88 × 10-14) were linked to an increased risk of depression, whereas higher levels of LRRN1 (P = 4.28 × 10-11) and ITGA11 (P = 3.68 × 10-9) were associated with a decreased risk. Dysregulation of the 157 proteins is correlated with brain regions implicated in depression, including the hippocampus and middle temporal gyrus. Additionally, these protein alterations were strongly correlated with stress-related events, including self-harm events, adult, and childhood trauma. Biological pathway enrichment analysis highlighted the critical roles of the immune response. EGFR and TNF emerged as key proteins in the protein-protein interaction network. BTN3A2, newly linked to incident depression (P = 4.35 × 10-10), was confirmed as a causal factor through Mendelian randomization analysis. In summary, our research identified the proteomic signatures associated with the onset of depression, highlighting its potential for early intervention and tailored therapeutic avenues.

Targeting QPCTL: An Emerging Therapeutic Opportunity

Glutaminyl cyclases, including glutaminyl-peptide cyclotransferase (QPCT) and glutaminyl-peptide cyclotransferase-like protein (QPCTL), primarily catalyze the cyclization of N-terminal glutamine or glutamate to pyroglutamate (pGlu). QPCTL, in particular, modifies the N-terminus of CD47, thereby regulating its interaction with signal-regulatory protein alpha (SIRPα) and modulating phagocytosis of tumor cells by immune cells. Additionally, QPCTL cyclizes the N-termini of CCL2, CCL7, and CX3CL1, influencing the tumor microenvironment and inflammatory responses in cancer and other disorders. Consequently, QPCTL is considered a valuable therapeutic target for several human diseases. However, the development of QPCTL inhibitors remains in its early stages. This perspective summarizes the structural features, catalytic mechanisms, and biological functions of QPCTL, along with its recent advances in small-molecule inhibitors. It provides valuable insights into the development of novel QPCTL inhibitors.

Progress of research on γδ T cells in colorectal cancer (Review)

Colorectal cancer (CRC) ranks as the third most prevalent malignancy and second leading cause of cancer‑related fatalities worldwide. Immunotherapy alone or in combination with chemotherapy has a favorable survival benefit for patients with CRC. Unlike αβ T cells, which are prone to drug resistance, γδ T cells do not exhibit major histocompatibility complex restriction and can target tumor cells through diverse mechanisms. Recent research has demonstrated the widespread involvement of Vδ1T, Vδ2T, and γδ T17 cells in tumorigenesis and progression. In the present review, the influence of different factors, including immune checkpoint molecules, the tumor microenvironment and microorganisms, was summarized on the antitumor/protumor effects of these cells, aiming to provide insights for the development of more efficient and less toxic immunotherapy‑based anticancer drugs.

Phosphoantigen recognition by Vγ9Vδ2 T cells

Vγ9Vδ2 T cells comprise 1-10% of human peripheral blood T cells. As multifunctional T cells with a strong antimicrobial and antitumor potential, they are of strong interest for immunotherapeutic development. Their hallmark is the eponymous Vγ9Vδ2 T-cell antigen receptor (TCR), which mediates activation by so-called "phosphoantigens" (PAg). PAg are small pyrophosphorylated intermediates of isoprenoid synthesis of microbial or host origin, with the latter elevated in some tumors and after administration of aminobisphosphonates. This review summarizes the progress in understanding PAg-recognition, with emphasis on the interaction between butyrophilins (BTN) and PAg and insights gained by phylogenetic studies on BTNs and Vγ9Vδ2 T cells, especially the comparison of human and alpaca. It proposes a composite ligand model in which BTN3A1-A2/A3-heteromers and BTN2A1 homodimers form a Vγ9Vδ2 TCR activating complex. An initiating step is the binding of PAg to the intracellular BTN3A1-B30.2 domain and formation of a complex with the B30.2 domains of BTN2A1. On the extracellular surface this results in BTN2A1-IgV binding to Vγ9-TCR framework determinants and BTN3A-IgV to additional complementarity determining regions of both TCR chains. Unresolved questions of this model are discussed, as well as questions on the structural basis and the physiological consequences of PAg-recognition.

X-ray Structure-Guided Discovery of a Potent Benzimidazole Glutaminyl Cyclase Inhibitor That Shows Activity in a Parkinson's Disease Mouse Model

The secretory glutaminyl cyclase (sQC) and Golgi-resident glutaminyl cyclase (gQC) are responsible for N-terminal protein pyroglutamation and associated with various human diseases. Although several sQC/gQC inhibitors have been reported, only one inhibitor, PQ912, is currently undergoing clinic trials for the treatment of Alzheimer's disease. We report an X-ray crystal structure of sQC complexed with PQ912, revealing that the benzimidazole makes "anchor" interactions with the active site zinc ion and catalytic triad. Structure-guided design and optimization led to a series of new benzimidazole derivatives exhibiting nanomolar inhibition for both sQC and gQC. In a MPTP-induced Parkinson's disease (PD) mouse model, BI-43 manifested efficacy in mitigating locomotor deficits through reversing dopaminergic neuronal loss, reducing microglia, and decreasing levels of the sQC/gQC substrates, α-synuclein, and CCL2. This study not only offers structural basis and new leads for drug discovery targeting sQC/gQC but also provides evidence supporting sQC/gQC as potential targets for PD treatment.