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Kupffer cell release of platelet activating factor drives dose limiting toxicities of nucleic acid nanocarriers.

ABSTRACT: This work establishes that Kupffer cell release of platelet activating factor (PAF), a lipidic molecule with pro-inflammatory and vasoactive signaling properties, dictates dose-limiting siRNA nanocarrier-associated toxicities. High-dose intravenous injection of siRNA-polymer nano-polyplexes (si-NPs) elicited acute, shock-like symptoms in mice, associated with increased plasma PAF and consequently reduced PAF acetylhydrolase (PAF-AH) activity. These symptoms were completely prevented by prophylactic PAF receptor inhibition or Kupffer cell depletion. Assessment of varied si-NP chemistries confirmed that toxicity level correlated to relative uptake of the carrier by liver Kupffer cells and that this toxicity mechanism is dependent on carrier endosome disruptive function. 4T1 tumor-bearing mice, which exhibit increased circulating leukocytes, displayed greater sensitivity to these toxicities. PAF-mediated toxicities were generalizable to commercial delivery reagent in vivo-jetPEI® and an MC3 lipid formulation matched to an FDA-approved nanomedicine. These collective results establish Kupffer cell release of PAF as a key mediator of siRNA nanocarrier toxicity and identify PAFR inhibition as an effective strategy to increase siRNA nanocarrier tolerated dose.

SUBMITTER: Jackson MA

PROVIDER: S-EPMC7856291 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BACKGROUND:Increasing evidence suggests that severe skeletal muscle index (SMI) loss (sarcopenia) is associated with poor overall survival in metastatic colorectal cancer patients, but its mechanisms are unknown. We recently found, using data of the randomized phase 3 CAIRO3 study, that SMI loss was related with shorter time to disease progression and overall survival during first-line maintenance treatment with capecitabine + bevacizumab (CAP-B) or observation and during more intensive capecitabine + oxaliplatin + bevacizumab (CAPOX-B) reintroduction treatment. As a potential risk factor for reduced survival, we explored whether sarcopenia and SMI loss were associated with dose-limiting toxicities (DLTs) during CAP-B and CAPOX-B. METHODS:Sarcopenia status and SMI loss were assessed by using consecutive computed tomography scans. DLTs were defined as any dose delay/reduction/discontinuation of systemic treatment because of reported CTCAE (version 3.0) toxicities at the start or during treatment. Poisson regression models were used to study whether sarcopenia and body mass index (BMI) at the start of treatment and SMI and BMI loss during treatment were associated with DLTs. RESULTS:One hundred eighty-two patients (mean age 63.0 ± 8.8 years, 37% female) received CAP-B, and 232 patients (mean age 63.0 ± 9.0 years, 34% female) received CAPOX-B. At the start of CAP-B and CAPOX-B, 54% and 46% of patients were sarcopenic, respectively. Mean BMI was lower in sarcopenic patients, although patients were on average still overweight (sarcopenic vs. non-sarcopenic at the start of CAP-B 25.0 ± 3.9 vs. 26.7 ± 4.1 and CAPOX-B 25.8 ± 3.8 vs. 27.1 ± 3.8 kg/m2 ). Sarcopenia at the start of CAP-B was not associated with DLTs [relative risk 0.87 (95% confidence interval 0.64-1.19)], whereas patients with >2% SMI loss had a significantly higher risk of DLTs [1.29 (1.01-1.66)]. At the start of subsequent CAPOX-B, 25% of patients received a dose reduction, and the risk of dose reduction was significantly higher for patients with preceding SMI loss [1.78 (1.06-3.01)] or sarcopenia [1.75 (1.08-2.86)]. After the received dose reductions, sarcopenia or SMI loss was not significantly associated with a higher risk of DLTs during CAPOX-B [sarcopenia vs. non-sarcopenic: 0.86 (0.69-1.08) and SMI loss vs. stable/gain: 0.83 (0.65-1.07)]. In contrast, BMI (loss) at the start or during either treatment was not associated with an increased risk of DLTs. CONCLUSIONS:In this large longitudinal study in metastatic colorectal cancer patients during palliative systemic treatment, sarcopenia and/or muscle loss was associated with an increased risk of DLTs. BMI was not associated with DLTs and could not detect sarcopenia or SMI loss. Prospective (randomized) studies should reveal whether normalizing chemotherapeutic doses to muscle mass or muscle mass preservation (by exercise and nutritional interventions) increases chemotherapeutic tolerance and improves survival.

Project description:Endothelin-3 (ET-3) stimulated phosphoinositide metabolism and synthesis of prostaglandins in cultured rat Kupffer cells. ET-3-induced hydrolysis of phosphoinositides was characterized by the production of various inositol phosphates and of glycerophosphoinositol. The mechanism of ET-3-stimulated metabolism of phosphoinositides and synthesis of prostaglandins appeared to be distinct from the effect of platelet-activating factor (PAF) on these processes described previously [Gandhi, Hanahan & Olson (1990) J. Biol. Chem. 265, 18234-18241]. On a molar basis ET-3 was significantly more potent than PAF in stimulating phosphoinositide metabolism, e.g. ET-3-induced hydrolysis of phosphoinositides occurred at 1 pM, whereas PAF was ineffective at concentrations less than 1 nM. Upon challenging Kupffer cells with both ET-3 and PAF, an additive stimulation of phosphoinositide metabolism was observed, suggesting that the actions of these factors may be exerted on separate phosphoinositide pools. Treatment of Kupffer cells with pertussis toxin resulted in an inhibition of ET-3-induced phospholipase C activation; in contrast, cholera toxin treatment caused potentiation of ET-3-stimulated phospholipase C activity. Both toxins, however, inhibited PAF-stimulated phospholipase C activity. The present results suggest that the stimulatory effects of ET-3 and PAF on the phosphodiesteric metabolism of phosphoinositides in Kupffer cells require different guanine-nucleotide-binding proteins. Furthermore, the effects of bacterial toxins on ET-3- and PAF-induced phosphoinositide metabolism were not mediated by cyclic AMP. ET-3-induced metabolism of phosphoinositides was inhibited completely in Kupffer cells pretreated with ET-3, suggesting homologous ligand-induced desensitization of the ET-3 receptors. In contrast, similar experiments using PAF showed only a partial desensitization of subsequent PAF-induced phosphoinositide metabolism. In contrast to the increased production of prostaglandins E2 and D2 observed upon stimulation of Kupffer cells with PAF, ET-3 stimulated the biosynthesis of prostaglandin E2 only. Consistent with their additive effects on phosphoinositide metabolism, PAF and ET-3 exhibited an additive stimulation of the synthesis of prostaglandin E2.

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Kupffer cell release of platelet activating factor drives dose limiting toxicities of nucleic acid nanocarriers.

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