Biology subjects

Chakrabarti, D.

Publications and source records attributed to Chakrabarti, D..

5 recordsLinked to original sources

bioRxiv2026

Differential Impact of Isoflurane and Propofol on Apoptotic Regulation of Helper T cells

BackgroundAnesthetic agents administered during surgery are one of the key perioperative factors affecting immune modulation in cancer patients. This comparative study elucidated the mechanisms by which the volatile anesthetic, isoflurane and the intravenous anesthetic, propofol impacted apoptosis signaling in CD4+ helper T (Th) cells. MethodsFlow cytometry was used to analyze apoptosis, mitochondrial function and reactive oxygen species (ROS) generation, while Western blotting, ELISA and RT-qPCR were employed to study protein/gene expression in sorted CD4{square} Th cells from perioperative breast cancer female patients (anesthetized with isoflurane or propofol, n=15 per group) and Jurkat T cells. ResultsPatient-derived CD4{square} Th cells and Jurkat T cells exhibited that isoflurane at clinically relevant concentrations triggered apoptosis through mitochondrial depolarization, ROS generation, DNA damage, and activation of caspase-3/7. Specific use of caspase-3/7 inhibitor, Z-DEVD-FMK and antioxidant N-acetyl cysteine rescued isoflurane-induced apoptosis. Further, isoflurane relative to propofol, activated p38 mitogen-activated protein kinase (MAPK), and use of p38 inhibitor, SB203580 suppressed isoflurane-induced apoptosis. Collectively, these findings validated the involvement of the ROS-p38-caspase-3/7 axis in isoflurane-associated apoptosis signaling. On the other hand, propofol conserved mitochondrial integrity, reduced oxidative stress, and maintained higher proliferative capacity. Interestingly, isoflurane-associated apoptosis was transient, with postoperative recovery in patients and similar rescue from apoptosis was evident in Jurkat T cells within 24-48 h of drug removal. ConclusionsBy integrating analyses of patient-derived CD4+ Th cells with mechanistic validations in Jurkat T cells, this study identified the ROS-p38-caspase-3/7 signaling axis and the reversible nature of isoflurane-induced apoptosis.

cancer biology↗

bioRxiv2026

Duplication of superoxide dismutase and a mutation in aquaglyceroporin mediates the sensitivity of Plasmodium falciparum to cryptosporin, a natural product derived from Acaromyces ingoldii

Cryptosporin, a fungal metabolite, exhibited potent antimalarial activity against both asexual blood stage Plasmodium falciparum and liver-stage Plasmodium berghei with minimal human HepG2 toxicity. Unlike atovaquone, cryptosporins mechanism is independent of mitochondrial electron transport. Minimum inoculum of resistance showed a low risk of resistance development. RNA-Seq analysis revealed the upregulation of genes associated with sexual development including many canonical markers such as Pfs25, and PfCCp3, suggesting a stress response that is also seen when parasites are treated with artemisinin. In vitro evolution and whole genome sequencing analysis identified a mutation (F138Y) in PfAQP (PF3D7_1132800) and duplications of the two superoxide dismutase genes, PfSOD-1 (PF3D7_0814900) and PfSOD-2 (PF3D7_0623500). CRISPR/Cas9 editing confirmed that the F138Y mutation in PfAQP was sufficient to confer resistance to cryptosporin. Alignment of the P. falciparum structure with that of HsAQP3 suggests the mutation may impact transport of hydrogen peroxide and the transition between open and closed conformations. Indeed, studies with BY4742 {Delta}fps1 yeast expressing PfAQP showed that the permeability of PfAQP was not affected by cryptosporin and that it is likely not a direct target. Taken together, this study highlights the role of PfAQP in the resistance development of cryptosporin. In addition, cryptosporin likely induces high levels of oxidative stress which results in the duplications of oxidative dismutase genes as part of the parasites defense response. These findings highlight the role of PfAQP in mediating drug resistance, the mechanism of which warrants further research.

genetics↗

bioRxiv2025

Norditerpene natural products from subterranean fungi with anti-parasitic activity

Cryptosporidium is a common, waterborne gastrointestinal parasite that causes diarrheal disease worldwide. Currently there are no effective therapeutics to treat cryptosporidiosis in at-risk populations. Since natural products are a known source of anti-parasitic compounds, we screened a library of extracts and pure natural product compounds isolated from bacteria and fungi collected from subterranean environments for activity against Cryptosporidium parvum. Eight structurally related norditerpene lactones isolated from the fungus Oidiodendron truncatum collected from the Soudan Iron mine in Minnesota showed potent activity and were further tested to identify the most active compounds. The availability of a diverse suite of natural structural analogs with varying activities allowed us to determine some structure activity relationships for both anti-parasitic activity as well as cytotoxicity. The two most potent compounds, oidiolactones A and B, had EC50s against intracellular Cryptosporidium parvum of 530 and 240 nM respectively without cytotoxicity to confluent HCT-8 host cells. Both compounds also inhibited the related parasite Toxoplasma gondii. Oidiolactone A was active against asexual, but not sexual, stages of C. parvum, and killed 80% of the parasites within 8 hours of treatment. This compound reduced C. parvum infection by 70% in IFN{gamma}-/- mice, with no signs of toxicity. The high potency, low cytotoxicity, and in vivo activity combined with high production, easy isolation from fungi, and synthetic accessibility make oidiolactones A and B attractive scaffolds for the development of new anti-Cryptosporidium therapeutics.

microbiology↗

bioRxiv2024

Distinct Proline residues in hinge-regions of SYMRK generates a phosphocode for releasing Malectin-like-Domain to allow progress of rhizobia-legume symbiosis at epidermal-cortical barrier.

Symbiosis Receptor Kinase (SYMRK), a malectin-like-domain/leucine-rich-repeat receptor-like-kinase (MLD-LRR-RLK), is the upstream most component in Common-Symbiosis-Signalling-Pathway. We highlight two Proline residues that were distinctly acquired by SYMRK orthologues in its hinge-regions to evolve a signalling module for allowing progress of symbionts across transcellular barriers during rhizobia-legume symbiosis. Within the Ectodomain hinge (EctoD-hinge) all MLD-LRR-RLKs have a conserved W1xnGDPCxnW2x4C motif, where SYMRK orthologues within legumes have a distinct signature with a Proline preceding W2 enabling cleavage of SYMRK-EctoD for releasing MLD. Within the kinase hinge (KD-hinge) at gatekeeper+1 position, a conserved Glutamate in MLD-LRR-RLKs is replaced by Proline in all SYMRK orthologues that enabled its dual-specific kinase activity for ensuring EctoD-cleavage. Substitution of either Proline restricted symbionts at the transcellular epidermal-cortical barrier forming infection patches in the nodule apex without affecting epidermal invasion and nodule organogenesis. This halt was entirely overcome by ectopic expression of free MLD demonstrating the released MLD to have an active role in progress of symbionts. Overall, we show that adaptations of distinct Prolines in hinge-regions of SYMRK orthologues in legumes have evolved a signalling module involving dimerization and optimal phosphorylation of SYMRK for releasing MLD as an active transducer of symbiosis signalling.

plant biology↗

bioRxiv2024

Rationally Minimizing Natural Product Libraries Using Mass Spectrometry

Natural product libraries are crucial to drug development, but large libraries drastically increase the time and cost during initial high throughput screens. Here, we developed a method that leverages liquid chromatography-tandem mass spectrometry spectral similarity to dramatically reduce library size, with minimal bioactive loss. This method offers a broadly applicable strategy for accelerated drug discovery with cost reductions, which enable implementation in resource-limited settings.

bioinformatics↗