Biology subjects

Kaushik, S. R.

Publications and source records attributed to Kaushik, S. R..

4 recordsLinked to original sources

bioRxiv2023

Iron chelation by deferoxamine as useful adjunct therapeutics in murine tuberculosis.

Dysregulated iron metabolism is reported in tuberculosis patients; therefore, it represents an opportunity for developing host-directed therapeutics. This study monitored the antimycobacterial properties of an iron chelator, i.e., Deferoxamine (DFO/D), and its impact on the transcript and metabolite levels of Mycobacterium tuberculosis (Mtb) in vitro. For in vivo validation, a group of mice received ferric carboxymaltose to create an iron overload condition, and controls were aerosol-infected with Mtb H37Rv. Mtb-infected mice received isoniazid (INH/H) and rifampicin (RIF/R) in combination with or without DFO before tissue-specific CFU assay, liver metabolite screening and iron quantification using mass spectrometry. DFO showed antimycobacterial properties comparable to INH in vitro. DFO treatment deregulated (log2DFO/control>{+/-}1.0) Mtb transcript (n=137) levels, the majority of which encode for iron-containing proteins and proteins involved in stress response. DFO treatment up-regulated Rv3622c (PE32), Rv2353c (PPE39) and Rv3022A (PE29) genes and conditional knocking down of ABC transporter like irtA by anhydrotetracycline (Atc) inducible CRISPR interference (CRISPRi) approach compromised Mtb growth showing their potential involvement in iron metabolism. Global Mtb metabolite analysis using GC-MS identified a set of 5 deregulated metabolites indicating a perturbed pentose phosphate pathway and inositol phosphate metabolism in the host upon DFO treatment. Iron-overloaded mice exhibited significantly higher tissue mycobacterial burden at two weeks post-infection, and the efficacy of INH and RIF were compromised, corroborating with previous reports. Iron chelation by DFO or combined with/adjunct to RIF and INH significantly reduced the lung/tissue mycobacterial burden at four weeks post-treatment, specifically in the first ([~]0.5 log) and second weeks ([~]0.5 log) of treatment. The intracellular pro-inflammatory cytokine levels in the lung CD4+ T cells of INH and RIF-treated groups with or without DFO were similar, suggesting DFO has a direct role in Mtb survival and metabolism rather than improved infection, and the efficacy of INH and RIF were compromised, corroborating with previous reports. DFO adjunct to RIF and INH treatment significantly altered liver arginine biosynthesis, which directly neutralizes ammonia and is immune-supportive. Conventionally, DFO is used for treating acute iron toxicity that is common in thalassemic patients, and this study demonstrates DFO has potential as adjunct therapeutics for tuberculosis. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/543389v3_ufig1.gif" ALT="Figure 1"> View larger version (52K): org.highwire.dtl.DTLVardef@5066fdorg.highwire.dtl.DTLVardef@99a292org.highwire.dtl.DTLVardef@80426dorg.highwire.dtl.DTLVardef@892436_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2020

Troxerutin acts on complement mediated inflammation to ameliorate arthritic symptoms in rats.

Troxerutin (TXR), is a phytochemical reported to possess anti-inflammatory and hepatoprotective effects. In this study, we aimed to exploit anti-arthritic properties of TXR using an adjuvant induced arthritic (AIA) rat model. AIA induced rats showed highest arthritis score at disease onset and by oral administration of TXR (50, 100, 200 mg/kg body weight), reduced to basal level in a dose dependent manner. Isobaric tag for relative and absolute quantitative (iTRAQ) proteomics tool was employed to identify deregulated joint homogenate proteins in AIA and TXR treated rats to decipher probable mechanism of the TXR action in arthritis. iTRAQ analysis identified a set of 434 joint homogenate proteins with 65 deregulated proteins (log2 case/control [≥]1.5) in AIA. Expressions of a set of important proteins (AAT, T-kininogen, vimentin, desmin, and nucleophosmin) that could classify AIA from healthy were validated using Western blot analysis. Western blot data corroborated proteomics findings. In silico protein-protein interaction study of joint homogenate proteome revealed that complement component 9, the major building blocks of the membrane attack complex (MAC) responsible for sterile inflammation, gets perturbed in AIA. Our dosimetry study suggests that a TXR dose of 200 mg/kg body weight for 15 days is sufficient to bring the arthritis score to basal levels in AIA rats. We have shown the importance of TXR as an anti-arthritis agent in AIA model and after additional investigation its arthritis ameliorating properties could be exploited for clinical usability.

biochemistry↗

bioRxiv2020

CMTM6 drives cisplatin resistance in OSCC by regulating AKT mediated Wnt signaling

Chemoresistance is one of the important factors for treatment failure in OSCC, which can culminate in progressive tumor growth and metastatic spread. Rewiring tumor cells to undergo drug-induced apoptosis is a promising way to overcome chemoresistance, which can be achieved by identifying the causative factors for acquired chemoresistance. In this study, to explore the key cisplatin resistance triggering factors, we performed global proteomic profiling of OSCC lines representing with sensitive, early and late cisplatin-resistant patterns. The top ranked up-regulated protein appeared to be CMTM6. We found CMTM6 to be elevated in both early and late cisplatin-resistant cells with respect to the sensitive counterpart. Analyses of OSCC patient samples indicate that CMTM6 expression is upregulated in chemotherapy-non-responder tumors as compared to chemotherapy-naive tumors. Stable knockdown of CMTM6 restores cisplatin-mediated cell death in chemoresistant OSCC lines. Similarly, upon CMTM6 overexpression in CMTM6KD lines, the cisplatin resistant phenotype was efficiently rescued. Mechanistically, it was found that CMTM6 interacts with membrane bound Enolase-1 and stabilized its expression, which in turn activates the AKT-GSK3{beta} mediated Wnt signaling. CMTM6 triggers the translocation of {beta}-catenin into the nucleus, which elevates the Wnt target pro-survival genes like Cyclin D, c-Myc and CD44. Moreover, incubation with lithium chloride, a Wnt signaling activator, efficiently rescued the chemoresistant phenotype in CMTM6KD OSCC lines. In a patient-derived cell xenograft model of chemoresistant OSCC, knock-down of CMTM6 restores cisplatin induced cell death and results in significant reduction of tumor burden. CMTM6 has recently been identified as a stabilizer of PD-L1 and henceforth it facilitates immune evasion by tumor cells. Herewith for the first time, we uncovered another novel role of CMTM6 as one of the major driver of cisplatin resistance.

cancer biology↗

bioRxiv2020

RRBP1 rewires cisplatin resistance in Oral Squamous Cell Carcinoma by regulating YAP-1

Cisplatin-based chemotherapy still remains as one of the primary treatment modalities for OSCC. Several OSCC patients experience relapse owing to development of chemoresistance. To identify key resistance triggering molecules, we performed global proteomic profiling of human OSCC lines presenting with sensitive, early and late cisplatin resistance patterns. From the proteomic profiling study, human RRBP1 was identified to be upregulated in both early and late cisplatin-resistant cells with respect to the sensitive counterpart. Analysis of OSCC patient sample indicates that RRBP1 expression is elevated in chemotherapy-non-responder tumors as compared to chemotherapy-naive tumors. Knocking out RRBP1 resulted in restoring cisplatin mediated cell death in chemoresistant lines and patient derived cells (PDC). Mechanistically, RRBP1 regulates YAP-1 to induce chemoresistance in OSCC. The chemoresistant PDC xenograft data suggests that knock out of RRBP1 induces cisplatin mediated cell death and facilitates a significant reduction of tumor burden. We also found Radezolid, a novel oxazolidinone antibiotic represses the expression of RRBP1 and restores cisplatin-induced cell death in chemoresistant OSCC. This unique combinatorial approach needs further clinical investigation to target advanced OSCC. Here with for the first time, we uncover the novel role of RRBP1 as potential modulator of cisplatin resistance in advanced OSCC.

cancer biology↗