Activation Motif Research Articles

Mapping immunological and host receptor binding determinants of SARS-CoV spike protein utilizing the Qubevirus platform

The motifs involved in tropism and immunological interactions of SARS-CoV spike (S) protein were investigated utilizing the Qubevirus platform. We showed that separately, 14 overlapping peptide fragments representing the S protein (F1-14 of 100 residues each) could be inserted into the C-terminus of A1 on recombinant Qubevirus without affecting its viability. Additionally, recombinant phage expression resulted in the surface exposure of different engineered fragments in an accessible manner. The F6 from S425-525, was found to contain the binding determinant of the recombinant human angiotensin converting enzyme 2 (rhACE2), with the shortest active binding motif situated between residues S437-492. Upstream, another fragment, F7, containing an overlapping portion of F6 would not bind to rhACE2, confirming that a contiguous stretch of residues could adopt the appropriate structural orientation of F6 as an insertion within the Qubevirus. The F6 (S441-460) and other inserts, including F7/F8 (S601-620) and F10 (S781-800), were demonstrated to contain important immunological determinants through recognition and binding of S protein specific (anti-S) antibodies. An engineered chimeric insert bearing the fusion of all three anti-S reactive epitopes, improved substantially the recognition and binding to their cognate antibodies. These results provide insights into humoral immune relevant epitopes and tropism characteristics of the S protein with implications for the development of subunit vaccines or other biologics against SARS-CoV.

Mesotrode chronic simultaneous mesoscale cortical imaging and subcortical or peripheral nerve spiking activity recording in mice.

Brain function originates from hierarchical spatial-temporal neural dynamics distributed across cortical and subcortical networks. However, techniques available to assess large-scale brain network activity with single-neuron resolution in behaving animals remain limited. Here, we present Mesotrode that integrates chronic wide-field mesoscale cortical imaging and compact multi-site cortical/subcortical cellular electrophysiology in head-fixed mice that undergo self-initiated running or orofacial movements. Specifically, we harnessed the flexibility of chronic multi-site tetrode recordings to monitor single-neuron activity in multiple subcortical structures while simultaneously imaging the mesoscale activity of the entire dorsal cortex. A mesoscale spike-triggered averaging procedure allowed the identification of cortical activity motifs preferentially associated with single-neuron spiking. Using this approach, we were able to characterize chronic single-neuron-related functional connectivity maps for up to 60 days post-implantation. Neurons recorded from distinct subcortical structures display diverse but segregated cortical maps, suggesting that neurons of different origins participate in distinct cortico-subcortical pathways. We extended the capability of Mesotrode by implanting the micro-electrode at the facial motor nerve and found that facial nerve spiking is functionally associated with the PTA, RSP, and M2 network, and optogenetic inhibition of the PTA area significantly reduced the facial movement of the mice. These findings demonstrate that Mesotrode can be used to sample different combinations of cortico-subcortical networks over prolonged periods, generating multimodal and multi-scale network activity from a single implant, offering new insights into the neural mechanisms underlying specific behaviors.

Mesotrode allows chronic simultaneous mesoscale cortical imaging and subcortical or peripheral nerve spiking activity recording in mice

Brain function originates from hierarchical spatial-temporal neural dynamics distributed across cortical and subcortical networks. However, techniques available to assess large-scale brain network activity with single-neuron resolution in behaving animals remain limited. Here, we present Mesotrode that integrates chronic wide-field mesoscale cortical imaging and compact multi-site cortical/subcortical cellular electrophysiology in head-fixed mice that undergo self-initiated running or orofacial movements. Specifically, we harnessed the flexibility of chronic multi-site tetrode recordings to monitor single-neuron activity in multiple subcortical structures while simultaneously imaging the mesoscale activity of the entire dorsal cortex. A mesoscale spike-triggered averaging procedure allowed the identification of cortical activity motifs preferentially associated with single-neuron spiking. Using this approach, we were able to characterize chronic single-neuron-related functional connectivity maps for up to 60 days post-implantation. Neurons recorded from distinct subcortical structures display diverse but segregated cortical maps, suggesting that neurons of different origins participate in distinct cortico-subcortical pathways. We extended the capability of Mesotrode by implanting the micro-electrode at the facial motor nerve and found that facial nerve spiking is functionally associated with the PTA, RSP, and M2 network, and optogenetic inhibition of the PTA area significantly reduced the facial movement of the mice. These findings demonstrate that Mesotrode can be used to sample different combinations of cortico-subcortical networks over prolonged periods, generating multimodal and multi-scale network activity from a single implant, offering new insights into the neural mechanisms underlying specific behaviors.

Resolving Atomic-Scale Structure and Chemical Coordination in High-Entropy Alloy Electrocatalysts for Structure-Function Relationship Elucidation.

The recent breakthrough in confining five or more atomic species in nanocatalysts, referred to as high-entropy alloy nanocatalysts (HEAs), has revealed the possibilities of multielemental interactions that can surpass the limitations of binary and ternary electrocatalysts. The wide range of potential surface configurations in HEAs, however, presents a significant challenge in resolving active structural motifs, preventing the establishment of structure-function relationships for rational catalyst design and optimization. We present a methodology for creating sub-5 nm HEAs using an aqueous-based peptide-directed route. Using a combination of pair distribution function and X-ray absorption spectroscopy, HEA structure models are constructed from reverse Monte Carlo modeling of experimental data sets and showcase a clear peptide-induced influence on atomic-structure and chemical miscibility. Coordination analysis of our structure models facilitated the construction of structure-function correlations applied to electrochemical methanol oxidation reactions, revealing the complex interplay between multiple metals that leads to improved catalytic properties. Our results showcase a viable strategy for elucidating structure-function relationships in HEAs, prospectively providing a pathway for future materials design.

A Phase I Study of CD19-Targeted 19(T2)28z1xx CAR T Cells in Adult Patients with Relapsed or Refractory Diffuse Large B-Cell Lymphoma

Background: Autologous CD19 CAR T cell therapies have demonstrated favorable clinical responses in relapsed or refractory (R/R) diffuse large B-cell lymphomas (DLBCL), but only a subset of patients (pts) experience durable remissions. We hypothesized that the redundancy of CD28 and CD3ζ signaling in a CAR design incorporating all 3 CD3ζ immunoreceptor tyrosine-based activation motifs (ITAMs) might negatively affect T cell differentiation and promote exhaustion. Therefore, we created a new CD19 CAR construct with calibrated CAR activation potential by mutating 2 of the 3 ITAMs, termed 1XX, and hypothesized that a 1XX CAR would afford durable responses at lower dose and fewer toxicities compared to CARs comprising 3 ITAMs. We previously presented the data from the dose-escalation portion of the phase I clinical trial of 19(T2)28z-1XX CAR T cells in DLBCL (Park J et al. ASH 2022). We have now completed accrual and report the updated results from both dose escalation and expansion portion of the study with a longer follow-up (NCT04464200). Methods: This is a single-center, phase I, dose-escalation and expansion trial of 19(T2)28z1XX CAR T cells in adult pts with R/R DLBCL conducted at Memorial Sloan Kettering Cancer Center. Pts received fludarabine and cyclophosphamide lymphodepleting chemotherapy followed by a single infusion of CAR T cells. There were 4 dose levels in the dose escalation cohort: dose level (DL) 1 (25x10 6), DL2 (50x10 6), DL3 (100x10 6) and DL4 (200x10 6 CAR T cells). The primary objective of the trial was to evaluate safety and tolerability and determine the recommended phase 2 dose. Key secondary objectives include assessment of overall response and complete response rates. Results: 28 pts have been enrolled and treated; 16 pts on the dose escalation and 12 pts on the dose expansion phase of the study. Median age was 62 (range, 48-86). 20 pts (71%) had primary refractory disease, 3 pts (11%) had prior autologous HSCT, and 2 pts (7%) had prior autologous CD19 CAR T therapy. In the dose-escalation phase (n=16), 15 pts experienced grade 1-2 CRS (94%) and no pt experienced ≥grade 3 CRS. Two pts (13%) experienced ICANS: 1 pt with grade 1 and 1 pt with grade 3 (Table 1). Eight pts received tocilizumab and 5 pts received corticosteroid. Complete response (CR) was observed in 11 of 16 pts (69%) and partial remission (PR) in 1 pt (6%) with overall response rate (ORR) of 75%. Responses were seen across all dose levels (Table 1). The lowest dose (DL1: 25x10 6) was selected for dose-expansion based on exposure-response analysis and 12 additional pts were treated at that dose level. In a pooled analysis of 16 pts who received DL1 dose (4 in dose escalation and 12 in dose expansion), 12 pts and 1 pt experienced grade 1-2 (75%) and grade 3 CRS (6%), respectively. Only 1 pt experienced ICANS (6%) at grade 3 (same pt who had grade 3 CRS), which was reversible and transient (Table 1). 11 pts received tocilizumab and 9 pts received corticosteroids. Twelve pts achieved CR (75%) and 2 pts (12%) PR with the best ORR of 87% (Table 1). A lower metabolic tumor volume (MTV) at screening but not at post-bridging was associated with a higher likelihood of achieving CR (p=0.039). With a median follow-up of 345 days (range, 33-1024), 4 pts experienced relapse (1 CR and 3 PR pts) and 16 pts have ongoing CR > 6 months (Figure 1). While CAR T cell persistence analysis is ongoing, 5 pts have CAR T cells detected beyond one year in ongoing CR including a patient treated at DL1 with detectable CAR T cells at 2 years. Conclusions: Treatment with 19(T2)28z1XX CAR T cells was shown to be safe with durable remissions with low rates of severe CRS (4%) and ICANS (7%). The overall CR rate of 71% is encouraging and appears durable with the majority of CR patients in ongoing remission > 6 months at a median follow-up of 345 days and with persisting CAR T cells. With more patients treated at DL1 with a longer follow-up, the study demonstrates a high efficacy of 19(T2)28z1XX CAR T cells at a dose significantly lower (25x10 6) than those of approved CD19 CAR T cells (100-300x10 6) and support that the 1XX single ITAM signaling domain may lead to enhanced efficacy of CD19 CARs and allow infusion of a lower T cell dose with favorable toxicity profiles.

Dual Split-Signaling TIM3+CLEC12a Targeting CAR T-Cells with Optimized Signaling As a Safe Potential Therapy for Acute Myeloid Leukemia

Background: The success of chimeric antigen receptor (CAR) T-cell therapies targeting B cell maturation antigen (BCMA) in multiple myeloma and CD19 in B-cell malignancies has demonstrated the immense potential of this immunotherapeutic strategy. However, the translation of CAR T-cell therapy to acute myeloid leukemia (AML) patients has encountered challenges due to the absence of surface antigens specifically or preferentially expressed on AML cells. To overcome this hurdle, we explored the feasibility and safety of simultaneously targeting the AML-associated antigens CLEC12a and TIM3 using an AND-gate strategy in which the essential stimulatory and co-stimulatory T-cell activation signals are segregated into separate CARs. To improve the safety of our strategy we also attenuated signaling through the stimulatory anti-CLEC12a CAR via affinity-optimization or through targeted mutations in its immunoreceptor tyrosine-based activation motif (ITAM) regions. Methods: To identify the most optimal dual-split CAR T-cell configuration, we designed several chimeric antigen receptor constructs in which we targeted CLEC12a with stimulatory CARs (sCARs) with high (C hi) or low (C low) affinities. In addition, the high affinity C hi stimulatory CAR was mutated in the second and third ITAM regions (denoted as C hixx) to attenuate the CD3ζ stimulatory signal. TIM3 was targeted by a costimulatory CAR (cCAR) containing both CD28 and 41BB signaling domains. The dual-split CARs were generated using two separate retroviral constructs. After the assessment of the CAR expression and specific surface markers associated with memory phenotype and exhaustion, dual-split CAR T-cells were functionally tested using an isogenic cell line model for specific lysis against dual CLEC12a/TIM3 positive or single CLEC12a or TIM3 positive isogenic target cells as well as for dual antigen-specific cytokine secretion. The dual-split CAR T-cells were also tested for their efficiency to specifically eliminate leukemic stem/progenitor cells by the colony formatting unit (CFU) assay. Moreover, anti-AML activity and persistence of the dual-split CAR T-cells was assessed using an AML PDX mouse model in which human primary AML cells expressing TIM3 and CLEC12a were injected. Results: Using the isogenic cell line model, we revealed that the dual-split CAR T-cells with the combination of the high affinity CLEC12a sCAR and TIM3 cCAR (C hi+T) show antigen-specific cytokine secretion and cytotoxicity, and that this specificity was enhanced when the CLEC12a sCAR was attenuated through ITAM mutations (C hixx+T). In CFU assays, all tested CLEC12a/TIM3 dual-split CAR T-cell combinations exhibited potent inhibition (up to 95%) of leukemia blast viability and leukemia stem/progenitor self-renewal. In vivo, although AML did not engraft in all mice, the best-performing dual-split C hixx+T1 CAR T-cells displayed potent anti-leukemic activity, as they prevented engraftment in two additional mice compared to control groups (n=6 each group). Furthermore, in contrast to control groups dual-split CAR T-cells exhibited prolonged persistence in the blood up to 20 weeks after injection. Conclusion: We successfully generated highly specific dual-targeting CAR T-cells by splitting the T-cell activation signals into two simultaneously expressed CARs, and using a novel approach of attenuating the sCAR through mutations in ITAM regions. Overall, we show that dual-split CAR T cells targeting CLEC12a and TIM3, particularly the combination C hixx+T CAR T-cells, have specific and promising anti-AML activity. Our findings underscore the potential of innovative dual-split CAR T-cell therapies as a novel and effective immunotherapeutic approach for combating AML.

KB-Lanra 1001: A Phase 1b/2 Study of Safety, PK, PD, and Preliminary Efficacy of the Selective SYK Inhibitor Lanraplenib in Combination with the FLT3 Inhibitor Gilteritinib in FLT3-Mutated R/R AML

Background and Significance: FMS-like tyrosine kinase (FLT3)-mutation (FLT3 mut) in patients with newly diagnosed and relapsed/refractory (R/R) acute myeloid leukemia (AML) is associated with shorter overall survival (OS) and relapse-free survival. Gilteritinib is an approved therapy for R/R FLT3 mut AML, but reduction in FLT3 mut burden and sustained efficacy are rarely achieved, thus necessitating investigation of rational therapeutic combinations to improve outcomes. Spleen Tyrosine Kinase (SYK) is a non-receptor tyrosine kinase known to regulate intracellular signaling in response to extracellular stimuli via its immunoreceptor tyrosine-based activation motif (ITAM). SYK serves as a relay to an oncogenic transcriptional regulatory network (TRN) linked to HOXA9 and MEIS1-facilitated suppression of myeloid progenitor maturation and proliferation. SYK cooperates with internal tandem duplication (ITD)-mutated FLT3 to drive leukemogenesis. Lanraplenib (LANRA) is an oral, potent, selective, next-generation SYK inhibitor with a 24-hour half-life, and once-daily (QD) dosing. In preclinical studies, the combination of LANRA and the FLT3 inhibitor gilteritinib demonstrated strong antileukemic effects ex vivo, resulting in deeper responses, and extended overall survival in FLT3 ITD-driven AML patient-derived xenograft mouse models. LANRA in combination with gilteritinib is currently being evaluated in patients with R/R FLT3 mut AML in the KB-LANRA 1001 trial (NCT05028751). Study Design and Methods: KB-LANRA 1001 is a global, multicenter, open-label phase 1b/2 trial designed to determine the safety and maximally tolerated and/or recommended phase 2 dose (MTD/RP2D) of LANRA in combination with standard dose gilteritinib (120 mg QD) in patients with R/R FLT3 mut AML. Secondary endpoints include evaluating pharmacokinetics (PK), pharmacodynamics (PD), and response evaluation (complete response (CR), CR with partial hematologic recovery (CRh), duration of response (DoR), event-free survival (EFS) and OS of the combination. Key exploratory endpoints include reduction of FLT3 mutvariant allele frequency among patients who achieve CR/CRh, correlation with selected baseline biomarkers that may predict efficacy outcomes, and assessment of LANRA PD properties (including target engagement). Eligibility requirements include documented FLT3 mut (ITD, tyrosine kinase domain [TKD] or both), age ≥18, and receipt of at least 1 prior therapy. Oral LANRA + gilteritinib will be administered daily until progression/relapse, intolerance, or failure to achieve at least a partial response (PR) after 6 cycles. The phase 1b component will follow a 3+3 dose escalation design. A dose-escalation committee (DEC) will decide LANRA dose escalation based on prospectively defined definitions of dose-limiting toxicity and safety metrics. Enrollment of additional patients to dose cohort(s) previously cleared for safety and tolerability by the DEC will be allowed under specific conditions. The phase 2 component will further evaluate safety, PK, PD, and anti-leukemic activity of the combination at the LANRA RP2D

Signaling Role of Viral Protein Motif and Its Application in CAR T Cell Therapy

Adoptive cell therapy using Chimeric Antigen Receptor (CAR) T cells, such as Tisagenlecleucel and Axicabtagene Ciloleucel, has revolutionized cancer immunotherapy and become a game-changer in cancer care. However, several challenges, including durable remission and limited expansion after infusion, persist. Recent work from the Riddell lab (PMID: 34429382) demonstrated that T Cell Receptors (TCRs) are more sensitive than CARs due to the presence of T cell signaling proteins like CD3-, CD3ε, and CD3-, which facilitate the recruitment of Lck to phosphorylate immunoreceptor tyrosine-based activation motifs (ITAMs). Although CARs were designed to mimic TCR signaling, they still lack the full sensitivity. In this study, we hypothesized that enhancing tyrosine phosphorylation of the immunoreceptor tyrosine-based activation motifs (ITAMs) presented on CD3 in CAR T cells amplifies the CAR-mediated signaling as well as improves sensitivity of CAR co-stimulatory signaling. To achieve this, we developed a novel co-stimulation system where anti-CD19 CAR T cells co-expressed Tip37, a 37-amino acid segment of the Herpesvirus saimiri (HVS) tyrosine-protein kinase-interacting protein (Tip). This specific segment interacts exclusively with the major T cell kinase, Lck, effectively regulating its kinase activation. The critical region for this interaction lies within 37 amino acids (146-182) in the central part of Tip, which contains two motifs: the SH3 binding motif (SH3B; 174-182) and the C-terminal Src-related kinase homology motif (CSKH; 146-155). The 37 amino acid peptide fragments alone form a stable complex with Lck. Lck is crucial in the initial stages of T cell activation, not only when triggered by the native TCR stimulation but also in response to CAR-antigen stimulation. Following antigen-induced T cell activation, Lck initiates the phosphorylation of tyrosines in the ITAMs present in CD3ζ domains. This leads to the recruitment of ZAP70 kinases to the ITAMs of CD3ζ, facilitating the formation of signaling protein complexes. The results of our in vitro experiments using the immortalized T cell line, Jurkat cells, demonstrate that the inclusion of the Tip37 component in the CAR leads to the formation of the Lck-CAR complex. This, in turn, significantly enhances the phosphorylation of ITAMs in CARs and triggers downstream signaling. Importantly, the CAR T cells with the Tip37 co-stimulatory domain do not secrete cytokines when in an unstimulated state. This suggests that the heightened Lck phosphorylation does not lead to the auto-activation of T cells. As a result, CAR T cells engineered with Tip37 can be considered safe and hold promise for future applications. We engineered CAR19 T cells co-expressing Tip (Tip-CART19 cells) with a co-stimulatory domain of 4-1BB and CD3 (Tip-CART19 cells). As a control, we generated CART19 cells lacking the TIP domain (WT CART19 cells). We confirmed that Tip expression induced enhanced CD3 phosphorylation in CART19 T cells. Additionally, we observed that a significantly augmented outgrowth of CD8+ cells engineered with the TIP-containing CAR compared with canonical CAR T cells. Further, TIP-CAR T cells displayed increased expression of CD38 and Ki67. Interestingly, we also noted an expansion of CCR7+CD45RA- central memory subsets in CD4+ CART19 cells and CCR7-CD45RA- effector memory subsets in CD8+ CART19 cells. Finally, as evidenced by apparent changes in phenotype, Tip-CART19 cells exhibited improved cytotoxic ability and significant outgrowth of CART19 cells with in vitro repeated CAR stimulation using CD19-expressing tumor cells, as previously described in our study (Fraietta et al., Nature 2018). This study highlights that amplification of the constitutive Lck recruitment and amplified CD3 phosphorylation in CART19 cells via the introduction of Tip37 domain results in enhanced anti-leukemia cytotoxic ability and preservation of proliferative function in CART19 cells. Our discovery introduces a novel approach for amplifying CAR signaling to improve CAR T cell therapy.

Recent advance: Sulfur ylides in organic synthesis

AbstractSulfur ylides are versatile structures that display various characteristics and participate in a myriad of reactions to produce simple, effective, and sometimes stereoselective reactions toward synthesizing sulfur‐containing compounds. Nonetheless, their fulfillment tremendous developments have been made in this field in the past few decades. In this comprehensive review, luminosity is illuminated on the application of sulfur ylides involved in various domino, cascade annulation reactions, and carbene trapping reagents with chameleonic reactivity. In the past numerous decennary, chemists have used sulfur ylides in solvent‐dependent, rhodium catalyzed, dealkylative intercepted, photochemical reaction, halotrifluoromethylation, benzannulation, amidation various name reactions such as Mizoroki–Heck, Suzuki–Miyaura, and Sommelet–Hauser rearrangements. Moreover, other prime applications include metal catalysis, epoxidation of carbonyl compounds, acylmethylation, cyclomerization, oxidation, and insertion reactions. Additionally, some sulfur ylides are extremely useful structures that play a major role in the synthesis of various medicinally active heterocycles structural motifs. This review article discusses all these reactions, their proposed mechanisms, and their application in the current scenario, at length. This tutorial review concludes by providing a future outlook on the investigation into sulfur ylides and various other compounds synthesized using it have great potential to be used in industries, laboratories, pharmaceutical companies, drug production, clinical use, medicinal chemistry, and agrochemical purposes.

Genome-Wide Investigation and Expression Analysis of the Catalase Gene Family in Oat Plants (Avena sativa L.).

Through the degradation of reactive oxygen species (ROS), different antioxidant enzymes, such as catalase (CAT), defend organisms against oxidative stress. These enzymes are crucial to numerous biological functions, like plant development and defense against several biotic and abiotic stresses. However, despite the major economic importance of Avena sativa around the globe, little is known about the CAT gene's structure and organization in this crop. Thus, a genome-wide investigation of the CAT gene family in oat plants has been carried out to characterize the potential roles of those genes under different stressors. Bioinformatic approaches were used in this study to predict the AvCAT gene's structure, secondary and tertiary protein structures, physicochemical properties, phylogenetic tree, and expression profiling under diverse developmental and biological conditions. A local Saudi oat variety (AlShinen) was used in this work. Here, ten AvCAT genes that belong to three groups (Groups I-III) were identified. All identified CATs harbor the two conserved domains (pfam00199 and pfam06628), a heme-binding domain, and a catalase activity motif. Moreover, identified AvCAT proteins were located in different compartments in the cell, such as the peroxisome, mitochondrion, and cytoplasm. By analyzing their promoters, different cis-elements were identified as being related to plant development, maturation, and response to different environmental stresses. Gene expression analysis revealed that three different AvCAT genes belonging to three different subgroups showed noticeable modifications in response to various stresses, such as mannitol, salt, and ABA. As far as we know, this is the first report describing the genome-wide analysis of the oat catalase gene family, and these data will help further study the roles of catalase genes during stress responses, leading to crop improvement.

Oxidative Folding Catalysts of Conotoxins Derived from the Venom Duct Transcriptome of C. frigidus and C. amadis.

Two novel redox conopeptides with proline residues outside and within the active site disulfide loop were derived from the venom duct transcriptome of the marine cone snails Conus frigidus and Conus amadis. Mature peptides with possible post-translational modification of 4-trans-hydroxylation of proline, namely, Fr874, Fr890[P1O], Fr890[P2O], Fr906, Am1038, and Am1054, have been chemically synthesized and characterized using mass spectrometry. The estimated reduction potential of cysteine disulfides of synthetic peptides varied from -298 to -328 mV, similar to the active site cysteine disulfide motifs of the redox family of proteins. Fr906/Am1054 exhibited pronounced catalytic activity and assisted in improving the yields of natively folded globular form α-conotoxin ImI. Three-dimensional (3D) structures of the redox conopeptides were optimized using computational methods and verified by 2D-ROESY NMR spectroscopy: C. frigidus peptides adopt an N-terminal helical fold and C. amadis peptides adopt distinct structures based on the Phe4-Pro/Hyp5 peptide bond configuration. The shift in the cis-trans configuration of the Phe4-Pro/Hyp5 peptide bond of Am1038/Am1054 was observed between reduced free thiol and oxidized disulfide forms of the optimized peptides. The report confirms the position-specific effect of hydroxyproline on the oxidative folding of conotoxins and sequence diversity of redox conopeptides in the venom duct of cone snails.

RIBOSOME-INACTIVATED PROTEINS (RIPS) OF THE BLACK ELDER SAMBUCUS NIGRA

The aim of this work is to study the composition of ribosome-inactivating proteins from the bark and berries of the black elderberry Sambucus nigra L., growing on the territory of the Republic of Uzbekistan.
 The composition of ribosome-inactivating proteins in the bark and berries of black elder Sambucus nigra L., collected in the Botanical Garden of the Republic of Uzbekistan, was studied. According to HPLC-MS/MS sequencing, the bark sample revealed the presence of 9 RIP-2. Based on the obtained amino acid sequences using the CLUSTAL O (1.2.4) program, the amino acid sequence of the identified type 2 RIPs was compared and similar and conserved residues were identified, which will further help identify new RIPs. In the course of the studies, the tryptic peptide LSLVVLQMVSEAAR containing the RIP active site motif (EAAR) was identified with a high degree of probability. Mass spectral data on this fragment will allow further identification of other RIP-1/2 from other samples of natural origin.
 2 RIPs were isolated from berries, one of which is in a reduced form containing one chain. Establishing the amino acid sequence in the isolated RIP from black elderberries with a molecular mass of 62337 Da confirmed our hypothesis of identification by the tryptic peptide containing the RIP active center (EAAR).

A novel Pinellia ternata catalase gene PtCAT2 regulates drought tolerance in Arabidopsis by modulating ROS balance.

Drought is one of the major abiotic stresses limiting agricultural production, particularly for shallow-rooted plants like Pinellia ternata. It damages plants via oxidative burst, but this effect could be mitigated by catalase (CAT). However, no studies have been reported on CAT homologs in P. ternata, a drought-sensitive plant species. In the present study, a novel CAT gene, PtCAT2, was functionally characterized via overexpression in Arabidopsis and analysis of cis-elements in its promoter. The isolated CAT gene was 1479 bp and encoded a protein containing 242 amino acids. The protein contains the CAT activity motif and the heme-binding site of a typical CAT, and the subcellular analysis indicated that the protein localizes at the cytoplasm and membrane. Moreover, the quantitative real-time reverse transcription PCR indicated that PtCAT2 is expressed ubiquitously in P. ternata and is strongly induced by drought stress and abscisic acid (ABA) signals. PtCAT2 overexpression enhanced the drought tolerance of Arabidopsis, as shown by the 30% increase in plant survival and a five-fold- increase in CAT activity. Moreover, PtCAT2-transgenic plants increased superoxide dismutase and peroxidase activities and reduced malondialdehyde, membrane leakage, and hydrogen peroxide (H2O2) (P<0.05). Furthermore, PtCAT2-transgenic plants showed higher tolerance to oxidative stress caused by exogenous H2O2 and retained higher chlorophyll and water contents than the WT. The mitochondria function was better maintained as presented by the higher oxygen consumption rate in transgenics under drought stress (P<0.05). The endogenous CATs and drought response-related genes were also upregulated in transgenic lines under drought stress, indicating that PtCAT2 confers drought stress tolerance by enhancing the H2O2 scavenging ability of plants to maintain their membrane integrity. These results improve our understanding of the drought response mechanisms and provide a potential breeding strategy for P. ternata genetic improvement.

Two APETALA2/ETHYLENE RESPONSE FACTORS coordinately with CaMYC2 positively regulate capsaicinoid biosynthesis in pepper (Capsicum annuum)

The transcriptional cascade and regulatory loop play crucial roles in regulating plant-specialized metabolite biosynthesis. Capsaicinoids are unique to the genus Capsicum and confer a pungent flavor to its fruits. However, the transcriptional regulation of capsaicinoid biosynthesis remains largely unknown. In this study, two AP2/ERF transcription factors (TFs), CaERF102 and CaERF111, were characterized for their role in the capsaicinoid biosynthesis process. Expression analysis of two ERFs and capsaicinoid biosynthetic genes (CBGs) suggested that they were associated with capsaicinoid biosynthesis. Both ERFs encode nuclear-localized proteins and function as transcriptional activators through their C-terminal activation motifs. The two ERF TFs participated in capsaicinoid biosynthesis by directly activating the promoters of key CBGs, and this activation was significantly enhanced when CaMYC2 was co-expressed. Moreover, CaERF102 and CaERF111 were found to interact with CaMYC2. This study helps elucidate the AP2/ERF TF regulatory network that governs capsaicinoid biosynthesis in Capsicum species.

Exceptional Lithium‐Ion Storage Performance on an Azo‐Bridged Covalent Heptazine Framework

AbstractGraphitic carbon nitride (g‐C3N4) possesses rich pyridine nitrogens, which is helpful for facilitating electrochemical capability in Li+ storage; however, its poor conductivity is still the main challenge. Based on the knowledge of its intrinsic merits and defects, here, it is proposed to integrate active heptazine (HEP) species with functional linkers into orderly molecular structures for improved performance. As the first proof‐of‐concept, a unique azo‐linked covalent heptazine framework (Azo‐CHF) where two HEP units are bridged with azo linkages, is ingeniously designed and prepared to enhance the inherent charge conductivity for Li+ storage. Attributing to the deeply extended conjugation along overlapping azo nitrogens and the aromatic π system of HEP cores, Azo‐CHF with the lowest bandgap (2.58 eV) exhibits enhanced Li+/e− transport than g‐C3N4 through density functional theory calculations. Therefore, the Azo‐CHF anode exhibits an unprecedented performance with a large reversible capacity (1723.0 mAh g−1 at 0.1 A g−1), superior rate capability (824.0 mAh g−1 at 10 A g−1), and impressive cyclability (756.5 mAh g−1 undergoing 1000 cycles at 10 A g−1). This study not only demonstrates the great application prospect of Azo‐CHF for Li+ storage, but also opens a fantastic window to further explore high‐performance electrodes by integrating HEP with other active motifs.

A Malassezia pseudoprotease dominates the secreted hydrolase landscape and is a potential allergen on skin

Malassezia globosa is abundant and prevalent on sebaceous areas of the human skin. Genome annotation reveals that M. globosa possesses a repertoire of secreted hydrolytic enzymes relevant for lipid and protein metabolism. However, the functional significance of these enzymes is uncertain and presence of these genes in the genome does not always translate to expression at the cutaneous surface. In this study we utilized targeted RNA sequencing from samples isolated directly from the skin to quantify gene expression of M. globosa secreted proteases, lipases, phospholipases and sphingomyelinases. Our findings indicate that the expression of these enzymes is dynamically regulated by the environment in which the fungus resides, as different growth phases of the planktonic culture of M. globosa show distinct expression levels. Furthermore, we observed significant differences in the expression of these enzymes in culture compared to healthy sebaceous skin sites. By examining the in situ gene expression of M. globosa's secreted hydrolases, we identified a predicted aspartyl protease, MGL_3331, which is highly expressed on both healthy and disease-affected dermatological sites. However, molecular modeling and biochemical studies revealed that this protein has a non-canonical active site motif and lacks measurable proteolytic activity. This pseudoprotease MGL_3331 elicits a heightened IgE-reactivity in blood plasma isolated from patients with atopic dermatitis compared to healthy individuals and invokes a pro-inflammatory response in peripheral blood mononuclear cells. Overall, our study highlights the importance of studying fungal proteins expressed in physiologically relevant environments and underscores the notion that secreted inactive enzymes may have important functions in influencing host immunity.

Functional Water Channels Within the TSH Receptor - a new paradigm for TSH action with disease implications.

The TSH receptor (TSHR) transmembrane domain (TMD) lives in the plasma membrane consisting of lipids and water molecules. To understand the role of TSHR-associated water molecules we used molecular dynamic simulations of the TMD and identified a network of putative receptor associated transmembrane water channels. This result was confirmed with extended simulations of the full length TSHR with and without TSH ligand binding. While the transport time observed in the simulations via the TSHR protein was slower than via the lipid bilayer itself we found that significantly more waters traversed via the TSHR than via the lipid bilayer which more than doubled with the binding of TSH. Using rat thyroid cells (FRTL-5) and a calcein fluorescence technique we measured cell volumes after blockade of aquaporins 1 and 4, the major thyroid cell water transporters. TSH showed a dose-dependent ability to influence water transport and similar effects were observed with stimulating TSHR autoantibodies. Small molecule TSHR agonists, which are allosteric activators of the TMD, also enhanced water transport illustrating the role of the TMD in this phenomenon. Furthermore, the water channel pathway was also mapped across two activation motifs within the TSHR TMD suggesting how water movement may influence activation of the receptor. In pathophysiological conditions such as hypothyroidism and hyperthyroidism where TSH concentrations are highly variable this action of TSH may greatly influence water movement in thyroid cells and many other extrathyroidal sites where the TSHR is expressed thus affecting normal cellular function.

Unveiling the enigmatic traits of Corynebacterium glutamicum mycoredoxin-3: A tiny redox protein displaying swapped homodimer formation and DsbA-like oxidase activity

Mycoredoxins (Mrxs) are a group of small dithiol oxidoreductases that share a conserved CXXC active site sequence motif resembling glutaredoxins. They are commonly found in saprophytic microorganisms, including Actinobacteria such as Mycobacterium tuberculosis. Among the known mycoredoxins, Corynebacterium glutamicum (Cg) Mrx1, featuring a conserved CVQC active site, functions as a mycothiol-dependent monothiol oxidoreductase. On the other hand, Mrx2, also known as NrdH-redoxin and containing the same CVQC motif, exhibits dithiol oxidoreductase properties and receives electrons from thioredoxin reductase (TrxR). Recently, it has been reported that CgMrx3, featuring a CGSC motif, acts as a thioredoxin, although its structural and biophysical characteristics remain unexplored.In this study, we successfully determined the X-ray structure of CgMrx3 at a resolution of 1.7 Å, revealing a swapped dimer arrangement. We compared the structure of CgMrx3 with those of CgMrx1 and CgMrx2 and with the AlphaFold2 predicted structure of Mrx3 from Mycobaterium tuberculosis (MtMrx3). We correlated the number of hydrogen bonds accepted by the nucleophilic cysteines with the relatively low pKa's determined for MtMrx3 and CgMrx3. Finally, we showed that CgMrx3 has DsbA-like oxidase activity. Taken together, our results provide valuable insights into the structural and functional characteristics of Mrx3, thereby enhancing our understanding of mycoredoxin-dependent redox biology.

Chalcone/1,3,4-Oxadiazole/Benzimidazole hybrids as novel anti-proliferative agents inducing apoptosis and inhibiting EGFR & BRAFV600E

IntroductionOne of the most robust global challenges and difficulties in the 21st century is cancer. Treating cancer is a goal which continues to motivate researchers to innovate in design and development of new treatments to help battle the disease.ObjectivesOur objective was developing new antiapoptotic hybrids based on biologically active heterocyclic motifs "benzimidazole?oxadiazole-chalcone hybrids'' that had shown promising ability to inhibit EGFR and induce apoptosis. We expected these scaffolds to display anticancer activity via inhibition of BRAF, EGFR, and Bcl-2 and induction of apoptosis through activation of caspases.MethodsThe new hybrids 7a-x were evaluated for their anti-proliferative, EGFR & BRAFV600E inhibitory, and apoptosis induction activities were detected. Docking study & dynamic stimulation into EGFR and BRAFV600E were studied.ResultsAll hybrids exhibited remarkable cell growth inhibition on the four tested cell lines with IC50 ranging from 0.95 μM to 12.50 μM. which was comparable to Doxorubicin. Compounds 7k-m had the most potent EGFR inhibitory activity. While, compounds 7e, 7g, 7k and 7l showed good inhibitory activities against BRAFV600E. Furthermore, Compounds 7k, 7l, and 7m increased Caspases 3,8 & 9, Cytochrome C and Bax levels and decreased Bcl-2 protein levels. Compounds 7k-m received the best binding scores and showed binding modes that were almost identical to each other and comparable with that of the co-crystalized Erlotinib in EGFR and BRAF active sites.ConclusionCompounds 7k-m could be used as potential apoptotic anti-proliferative agents upon further optimization.

Antiviral mechanisms of sorafenib against foot-and-mouth disease virus via c-RAF and AKT/PI3K pathways.

Foot-and-mouth disease virus (FMDV) is a highly contagious pathogen that poses a significant threat to the global livestock industry. However, specific antiviral treatments against FMDV are currently unavailable. This study aimed to evaluate the antiviral activity of anticancer drugs, including kinase and non-kinase inhibitors against FMDV replication in BHK-21 cells. Sorafenib, a multi-kinase inhibitor, demonstrated a significant dose-dependent reduction in FMDV replication. It exhibited a half maximal effective concentration (EC50) value of 2.46µM at the pre-viral entry stage and 2.03µM at the post-viral entry stage. Further intracellular assays revealed that sorafenib effectively decreased 3Dpol activity with a half maximal inhibitory concentration (IC50) of 155nM, while not affecting 3Cpro function. The study indicates that sorafenib influences host protein pathways during FMDV infection, primarily by potentiating the c-RAF canonical pathway and AKT/PI3K pathway. Molecular docking analysis demonstrated specific binding of sorafenib to the active site of FMDV 3Dpol, interacting with crucial catalytic residues, including D245, D338, S298, and N307. Additionally, sorafenib exhibited significant binding affinity to the active site motifs of cellular kinases, namely c-RAF, AKT, and PI3K, which play critical roles in the viral life cycle. The findings suggest that sorafenib holds promise as a therapeutic agent against FMDV infection. Its mechanism of action may involve inhibiting FMDV replication by reducing 3Dpol activity and regulating cellular kinases. This study provides insights for the development of novel therapeutic strategies to combat FMDV infections.