Role of pattern recognition receptors in chemotherapy-induced neuropathic pain

doi:10.1093/brain/awad339

. 2024 Mar 1;147(3):1025-1042.

doi: 10.1093/brain/awad339.

Role of pattern recognition receptors in chemotherapy-induced neuropathic pain

Dionéia Araldi¹, Eugen V Khomula¹, Ivan J M Bonet¹, Oliver Bogen¹, Paul G Green^{1

2}, Jon D Levine^{1

3}

Affiliations

¹ Department of Oral and Maxillofacial Surgery, UCSF Pain and Addiction Research Center, University of California at San Francisco, San Francisco, CA 94143, USA.
² Department of Preventative and Restorative Dental Sciences, Division of Neuroscience, University of California at San Francisco, San Francisco, CA 94143, USA.
³ Department of Medicine, Division of Neuroscience, University of California at San Francisco, San Francisco, CA 94143, USA.

PMID: 37787114
PMCID: PMC10907096
DOI: 10.1093/brain/awad339

Role of pattern recognition receptors in chemotherapy-induced neuropathic pain

Dionéia Araldi et al. Brain. 2024.

. 2024 Mar 1;147(3):1025-1042.

doi: 10.1093/brain/awad339.

Authors

Dionéia Araldi¹, Eugen V Khomula¹, Ivan J M Bonet¹, Oliver Bogen¹, Paul G Green^{1

2}, Jon D Levine^{1

3}

Affiliations

¹ Department of Oral and Maxillofacial Surgery, UCSF Pain and Addiction Research Center, University of California at San Francisco, San Francisco, CA 94143, USA.
² Department of Preventative and Restorative Dental Sciences, Division of Neuroscience, University of California at San Francisco, San Francisco, CA 94143, USA.
³ Department of Medicine, Division of Neuroscience, University of California at San Francisco, San Francisco, CA 94143, USA.

PMID: 37787114
PMCID: PMC10907096
DOI: 10.1093/brain/awad339

Abstract

Progress in the development of effective chemotherapy is producing a growing population of patients with acute and chronic painful chemotherapy-induced peripheral neuropathy (CIPN), a serious treatment-limiting side effect for which there is currently no US Food and Drug Administration-approved treatment. CIPNs induced by diverse classes of chemotherapy drugs have remarkably similar clinical presentations, leading to the suggestion they share underlying mechanisms. Sensory neurons share with immune cells the ability to detect damage associated molecular patterns (DAMPs), molecules produced by diverse cell types in response to cellular stress and injury, including by chemotherapy drugs. DAMPs, in turn, are ligands for pattern recognition receptors (PRRs), several of which are found on sensory neurons, as well as satellite cells, and cells of the immune system. In the present experiments, we evaluated the role of two PRRs, TLR4 and RAGE, present in dorsal root ganglion (DRG), in CIPN. Antisense (AS)-oligodeoxynucleotides (ODN) against TLR4 and RAGE mRNA were administered intrathecally before ('prevention protocol') or 3 days after ('reversal protocol') the last administration of each of three chemotherapy drugs that treat cancer by different mechanisms (oxaliplatin, paclitaxel and bortezomib). TLR4 and RAGE AS-ODN prevented the development of CIPN induced by all three chemotherapy drugs. In the reversal protocol, however, while TLR4 AS-ODN completely reversed oxaliplatin- and paclitaxel-induced CIPN, in rats with bortezomib-induced CIPN it only produced a temporary attenuation. RAGE AS-ODN, in contrast, reversed CIPN induced by all three chemotherapy drugs. When a TLR4 antagonist was administered intradermally to the peripheral nociceptor terminal, it did not affect CIPN induced by any of the chemotherapy drugs. However, when administered intrathecally, to the central terminal, it attenuated hyperalgesia induced by all three chemotherapy drugs, compatible with a role of TLR4 in neurotransmission at the central terminal but not sensory transduction at the peripheral terminal. Finally, since it has been established that cultured DRG neurons can be used to study direct effects of chemotherapy on nociceptors, we also evaluated the role of TLR4 in CIPN at the cellular level, using patch-clamp electrophysiology in DRG neurons cultured from control and chemotherapy-treated rats. We found that increased excitability of small-diameter DRG neurons induced by in vivo and in vitro exposure to oxaliplatin is TLR4-dependent. Our findings suggest that in addition to the established contribution of PRR-dependent neuroimmune mechanisms, PRRs in DRG cells also have an important role in CIPN.

Keywords: Toll-like receptor 4 (TLR4); bortezomib; chemotherapy-induced peripheral neuropathy (CIPN); oxaliplatin; paclitaxel; receptor for advanced glycation endproducts (RAGE).

PubMed Disclaimer

Conflict of interest statement

The authors report no competing interests.

Figures

**Figure 1**
**Time-dependent symmetric decrease in mechanical nociceptive threshold produced by oxaliplatin, paclitaxel and bortezomib**. Oxaliplatin [2 mg/kg, intravenously (i.v.), on Day 0], paclitaxel [1 mg/kg, intraperitoneally (i.p.), on Days 0, 2, 4 and 6] or bortezomib (0.2 mg/kg, i.v., on Days 0, 2, 4 and 6) were administered to groups of male rats, and the magnitude of hyperalgesia was measured over 28 days. *Top*: Oxaliplatin decreased the nociceptive threshold from the first time point (30 min), and it remained undiminished over the 28-day testing period. For paclitaxel and bortezomib, the time-dependent decrease in the nociceptive threshold reached a maximum on Day 7 and remained undiminished for the rest of the 28-day testing period. *Bottom*: A symmetry index was calculated at every time point, as the absolute (unsigned) value of the difference between the reduction in nociceptive threshold in the right minus left paws, for each rat, expressed as a percentage of the baseline nociceptive threshold. There was no time dependence of the symmetry index for any of the three agents tested, and the average levels remained very low at all time points (mean values: oxaliplatin 4.4%, paclitaxel 6.0% and bortezomib 3.3%), supporting the presence of symmetry in hind paw mechanical hyperalgesia throughout the time course of the study (Days 0–28) for all three chemotherapy drugs. Values are presented as mean ± SEM; n = 12 for oxaliplatin- and paclitaxel-, and n = 8 for bortezomib-treated rats.

**Figure 2**
**Effect of TLR4 antisense on preventing and reversing oxaliplatin, paclitaxel and bortezomib CIPN.** *Top*: Groups of male rats were treated intrathecally (i.t.) with antisense (AS)-oligodeoxynucleotides (ODN) or mismatch (MM)-ODN (both 120 μg in 20 μl/day) against TLR4 mRNA, once a day starting 3 days before (Day −3) each chemotherapy drug, for seven doses, over 10 days. Rats received (A) oxaliplatin [2 mg/kg, intravenously (i.v.), on Day 0]; (B) paclitaxel [1 mg/kg, intraperitoneally (i.p.), on Days 0, 2, 4 and 6]; or (C) bortezomib (0.2 mg/kg, i.v., on Days 0, 2, 4 and 6). The mechanical nociceptive threshold was evaluated before the first intrathecal administration of ODN (Day −3) and then from Days 0 to 28. In the TLR4 antisense-treated rats, CIPN hyperalgesia was markedly inhibited in the oxaliplatin-, paclitaxel- and bortezomib-treated rats (A, B and C, respectively), and this attenuation was undiminished over the 28-day testing period (all data are mean ± SEM). Statistical analyses for (A) oxaliplatin: two-way repeated-measures ANOVA, Time × TLR4 AS-ODN interaction, F(6,60) = 27.22, P < 0.0001; TLR4 AS-ODN treatment, F(1,10) = 210.6, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ****P < 0.0001 (TLR4 MM-ODN versus TLR4 AS-ODN); (B) paclitaxel: two-way repeated-measures ANOVA, Time × TLR4 AS-ODN interaction, F(7,70) = 39.54, P < 0.0001; TLR4 AS-ODN treatment, F(1,10) = 333.2, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ****P < 0.0001, ***P = 0.0001, *P = 0.0299 (TLR4 MM-ODN versus TLR4 AS-ODN); and (C) ortezomib; two-way repeated-measures ANOVA, Time × TLR4 AS-ODN interaction, F(6,60) = 7.817, P < 0.0001; TLR4 AS-ODN treatment, F(1,10) = 280.8, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ****P < 0.0001, ***P = 0.0004 (TLR4 MM-ODN versus TLR4 AS-ODN). n = 6 paws for each group. *Bottom*: Separate groups of male rats received: (D) oxaliplatin (2 mg/kg, i.v., on Day 0); (E) paclitaxel (1 mg/kg, i.p., on Days 0, 2, 4 and 6); or (F) bortezomib (0.2 mg/kg, i.v., on Days 0, 2, 4 and 6). Each group was then treated intrathecally with AS-ODN or MM-ODN (both 120 μg in 20 μl/day) against TLR4 mRNA once a day starting 3 days after the last dose of chemotherapy agent, for seven doses, over 10 days. The mechanical nociceptive threshold was evaluated from Days 0 to 28. In the TLR4 AS-ODN-treated group, CIPN hyperalgesia was markedly attenuated in oxaliplatin- and paclitaxel-treated rats, and this attenuation was undiminished for the 28-day testing period. Bortezomib-induced hyperalgesia was reversed on Day 14, but hyperalgesia returned, after ending antisense administration, on Days 21 and 28. Statistical analyses for (D) oxaliplatin: two-way repeated-measures ANOVA, Time × TLR4 AS-ODN interaction, F(5,50) = 41.94, P < 0.0001; TLR4 AS-ODN treatment, F(1,10) = 67.68, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ^aaaP = 0.0002, ***P = 0.0008, ****P < 0.0001, ^cccP = 0.0001 (MM-ODN versus AS-ODN); (E) paclitaxel: two-way repeated-measures ANOVA, Time × TLR4 AS-ODN interaction, F(4,40) = 75.11, P < 0.0001; TLR4 AS-ODN treatment, F(1,10) = 100.6, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ****P < 0.0001 (MM-ODN versus AS-ODN); and (F) bortezomib: two-way repeated-measures ANOVA, Time × TLR4 AS-ODN interaction, F(6,60) = 44.08, P < 0.0001; TLR4 AS-ODN treatment, F(1,10) = 23.6, P = 0.0007; Bonferroni's multiple *post hoc* comparisons test, ****P < 0.0001 (MM-ODN versus TLR4 AS-ODN at Day 14 after first bortezomib administration). All data are mean ± SEM. n = 6 paws for each group. CIPN = chemotherapy-induced peripheral neuropathy.

**Figure 3**
**TLR4 antisense attenuates TLR4 protein expression in L4 and L5 dorsal root ganglia and oxaliplatin-induced CIPN.** Western blot analysis of dorsal root ganglia (DRG) extracts from male rats treated intrathecally with antisense-oligodeoxynucleotides (AS-ODN) against TLR4 mRNA, once a day for 4 days (120 µg in 20 µl/day). (A) TLR4 AS-ODN-treatment significantly decreased anti-TLR4 immunoreactivity 24 h after the last treatment (−28.06 ± 1.29%, unpaired Student's t-test, n = 3, *P < 0.05). Of note, the magnitude of the attenuation of TLR4 in DRG neurons is probably an underestimate, as TLR4 levels in other cells in the DRG are not affected by intrathecal antisense but are measured on the western blots. (B) Nine days after the last administration of TLR4 AS-ODN, anti-TLR4 immunoreactivity was not significantly different from the levels in DRG from TLR4 mismatch (MM)-ODN-treated rats (−2.32 ± 3.6%, unpaired Student's t-test, n = 3, P > 0.05). The calculated molecular weight of TLR4 is 96 kDa (according to UniProtKB database entry Q9QX05). The difference between the calculated and apparent molecular weights may be due to the glycosylation of TLR4. β-Actin, which was used as a loading control, has a calculated molecular weight of ∼42 kDa (according to UniProtKB database entry P60771). The full-length gels and blots are included in Supplementary Fig. 3. (C) Male rats were treated intrathecally with AS-ODN or MM-ODN (both 120 μg in 20 μl/day) against TLR4 mRNA once a day for 4 days consecutively. On Day 0 (9 days after the last intrathecal ODN injection), rats received oxaliplatin [2 mg/kg, intravenously (i.v.)], and the mechanical nociceptive threshold was evaluated before the first intrathecal administration of ODN (Day −12) and then from Days 0 to 28. In the TLR4 AS-ODN-treated group, oxaliplatin did not develop hyperalgesia until Day 28. Two-way repeated-measures ANOVA, Time × TLR4 AS-ODN interaction, F(6,60) = 35.66, P < 0.0001; TLR4 AS-ODN treatment, F(1,10) = 881.1, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ****P < 0.0001 (TLR4 MM-ODN versus TLR4 AS-ODN). n = 6 paws for each group. All data are mean ± SEM. CIPN = chemotherapy-induced peripheral neuropathy.

**Figure 4**
**Intrathecal but not intradermal administration of a TLR4 selective antagonist reverses oxaliplatin, paclitaxel and bortezomib CIPN**. *Top*: Groups of male rats received (A and D) oxaliplatin [2 mg/kg, intravenously (i.v.), on Day 0]; (B and E) paclitaxel [1 mg/kg, intraperitoneally (i.p.), on Days 0, 2, 4 and 6]; or (C and F) bortezomib (0.2 mg/kg, i.v., on Days 0, 2, 4 and 6). The mechanical nociceptive threshold was evaluated on Day 0 before the chemotherapy drug was administered and then at Day 28 after their administration. On Day 28 after chemotherapy drugs, rats received intradermal vehicle (saline, 5 μl) or TLR4 antagonist (LPS-RS Ultrapure, 3 μg/5 μl), and the mechanical nociceptive threshold was evaluated 30 and 60 min later. Intradermal TLR4 antagonist did not attenuate CIPN hyperalgesia in the oxaliplatin-, paclitaxel- and bortezomib-treated rats (A, B and C, respectively). Statistical analyses for intradermal TLR4 antagonist (A) oxaliplatin: two-way repeated-measures ANOVA, Time × TLR4 antagonist interaction, F(3,12) = 0.749, P = 0.5434; TLR4 antagonist treatment, F(1,10) = 0.347, P = 0.5876; Bonferroni's multiple *post hoc* comparisons test, not significant (ns; vehicle versus TLR4 antagonist); (B) paclitaxel: two-way repeated-measures ANOVA, Time × TLR4 antagonist interaction, F(3,12) = 1.136, P = 0.3738; TLR4 antagonist treatment, F(1,10) = 2.009, P = 0.3393; Bonferroni's multiple *post hoc* comparisons test, ns (vehicle versus TLR4 antagonist); and (C) bortezomib: two-way repeated-measures ANOVA, Time × TLR4 antagonist interaction, F(3,12) = 2.157, P = 0.1462; TLR4 antagonist treatment, F(1,10) = 1.382, P = 0.3050; Bonferroni's multiple *post hoc* comparisons test, ns (vehicle versus TLR4 antagonist). n = 6 paws for each group. *Bottom*: Separate groups of male rats, treated 28 days prior with (D) oxaliplatin (2 mg/kg, i.v.), (E) paclitaxel (1 mg/kg, i.p.) or (F) bortezomib (0.2 mg/kg, i.v.), received intrathecally vehicle (saline, 20 μl) or TLR4 antagonist (LPS-RS Ultrapure, 10 μg/20 μl), and the mechanical nociceptive threshold was evaluated 30, 60 and 120 min later. In the group treated with intrathecal TLR4 antagonist, oxaliplatin-, paclitaxel- and bortezomib-induced hyperalgesia was markedly attenuated (D, E and F, respectively), and this inhibition was undiminished for the 120-min testing period. Statistical analyses for intrathecal TLR4 antagonist (D) oxaliplatin: two-way repeated-measures ANOVA, Time × TLR4 antagonist interaction, F(4,40) = 74.54, P < 0.0001; TLR4 antagonist treatment, F(1,10) = 168.3, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ****P < 0.0001 (vehicle versus TLR4 antagonist); (E) paclitaxel; two-way repeated-measures ANOVA, Time × TLR4 antagonist interaction, F(4,40) = 73.01, P < 0.0001; TLR4 antagonist treatment, F(1,10) = 216.8, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ****P < 0.0001 (vehicle versus TLR4 antagonist); and (F) bortezomib: two-way repeated-measures ANOVA, Time × TLR4 antagonist interaction, F(4,32) = 32.66, P < 0.0001; TLR4 antagonist treatment, F(1,10) = 30.99, P = 0.0005; Bonferroni's multiple *post hoc* comparisons test, ^aP = 0.0341, *P = 0.0248, ^cP = 0.0252 (vehicle versus TLR4 antagonist). n = 6 paws for each group. All data are mean ± SEM. LPS-RS Ultrapure = lipopolysaccharide from *Rhodobacter sphaeroides*. CIPN = chemotherapy-induced peripheral neuropathy.

**Figure 5**
**Oxaliplatin-induced nociceptor sensitization, *in vitro*, is TLR4 dependent**. (A) Example traces for the lower (more negative) action potential (AP) threshold in a small dorsal root ganglia (DRG) neuron of an oxaliplatin-treated rat (*middle*) compared with naïve rats (*left*), and the lack of such oxaliplatin-induced lowering of the AP threshold after *in vivo* pretreatment with TLR4 antisense-oligodeoxynucleotides (AS-ODN) in the prevention protocol (*right*). Traces show APs generated in response to a current step with height equal to rheobase (minimum current required to induce an AP) in three different neurons. The scale is the same for all panels. AP threshold is indicated by short grey tick. Rectangle *inset* in the *upper right* corner of each panel shows magnified region of recordings near the position of the AP threshold. Thin light grey line shows fit of the initial phase of the depolarization with a single exponent corresponding to passive charging of the neuron's capacitance. Deviation of the actual neuronal depolarization of 2 mV above the fit was defined as the AP threshold (see the ‘Materials and methods’ section for details). (B) Effect of oxaliplatin administered *in vivo* on AP threshold, and the attenuation of this effect by TLR4 AS-ODN administered *in vivo*, in the prevention protocol. Oxaliplatin induced a reduction in the AP threshold compared with the control group [untreated naïve animals; one-way ANOVA: F(2,26) = 6.3, P = 0.006; Holm–Šídák's *post hoc* test: t(26) = 3.6, **adjusted P = 0.003]. TLR4 AS-ODN administered before oxaliplatin produced a significant shift in the AP threshold back towards the control value [t(26) = 2.1, ^#adjusted P = 0.04 compared with *in vivo* oxaliplatin]. (C) Effect of *in vitro* administration of oxaliplatin on the AP threshold, and its attenuation by TLR4 AS-ODN administered *in vivo*, in the prevention protocol. Oxaliplatin (50 μM) induced a significant reduction in the AP threshold (after preincubation for 3 h before recording) compared with the control group [one-way ANOVA: F(2,29) = 10.5, P = 0.0004; Dunnett's *post hoc* test: q(29) = 4.1, ***adjusted P = 0.0005]. TLR4 AS-ODN administered *in vivo*, before oxaliplatin, produced a significant shift in the AP threshold back towards the control value [Dunnett's *post hoc* test: q(29) = 3.9, ^##adjusted P = 0.0010 compared with *in vitro* oxaliplatin]. (D) Effect of *in vitro* administration of LPS-RS Ultrapure, a selective inhibitor of TLR4, on oxaliplatin-induced reduction in AP threshold (‘all *in vitro*’ prevention). Preincubation of cultured neurons with LPS-RS Ultrapure (10 μg/ml for 24 h) before adding oxaliplatin (for 3 h before and during the recording) significantly shifted the AP threshold back towards the control value compared with the significantly more negative AP threshold observed in *in vitro* oxaliplatin-treated neurons [one-way ANOVA: F(2,28) = 7.0, P = 0.004; Dunnett's *post hoc* test: q(25) = 3.7, **adjusted P = 0.0018 for *in vitro* oxaliplatin, when compared with control; q(28) = 2.4, ^#adjusted P = 0.04 for LPS-RS Ultrapure, when compared with *in vitro* oxaliplatin]. (E) Effect of LPS-RS Ultrapure administered *in vitro* on AP threshold in neurons derived from animals treated with oxaliplatin *in vivo* (*in vitro* reversal after *in vivo* induction of nociceptor sensitization). Incubation of such neurons with LPS-RS Ultrapure (10 μg/ml for 24 h) produced a significant shift in the AP threshold back towards the control value when compared with the significantly more negative AP threshold observed in neurons from oxaliplatin-treated animals [one-way ANOVA: F(2,25) = 9.5, P = 0.0009; Dunnett's *post hoc* test: q(25) = 3.7, **adjusted P = 0.0019 for *in vivo* oxaliplatin, when compared with control; q(25) = 3.9, ^##adjusted P = 0.0014 for LPS-RS Ultrapure, when compared with *in vivo* oxaliplatin]. Number of cells: B, C, D and E share the same data set for the control group (*left* bars), n = 14; B and E share the same data set for the *in vivo* oxaliplatin group (*middle* bars), n = 8; C and D share the same dataset for the *in vitro* oxaliplatin group (*middle* bars), n = 9. Number of cells in prevention or reversal groups (*right* bars): n = 7 in B, n = 9 in C, n = 8 in D, n = 6 in E. LPS-RS Ultrapure = lipopolysaccharide from *Rhodobacter sphaeroides*.

**Figure 6**
**RAGE antisense prevents and reverses oxaliplatin, paclitaxel and bortezomib CIPN.** *Top*: Separate groups of male rats were treated intrathecally (i.t.) with antisense (AS)- or sense (SE)-oligodeoxynucleotides (ODN) (both 120 μg in 20 μl/day) against RAGE mRNA, once a day, starting 3 days before the chemotherapy agents, for seven doses, over 10 days. Rats received: (A) oxaliplatin [2 mg/kg, intravenously (i.v.), on Day 0]; (B) paclitaxel [1 mg/kg, intraperitoneally (i.p.), on Days 0, 2, 4 and 6]; or (C) bortezomib (0.2 mg/kg, i.v., on Days 0, 2, 4 and 6). The mechanical nociceptive threshold was evaluated before the first intrathecal administration of ODN (Day −3) and then from Days 0 to 28. In the RAGE AS-ODN-treated groups, CIPN hyperalgesia was markedly inhibited in the oxaliplatin-, paclitaxel- and bortezomib-treated rats (A, B and C, respectively), and this attenuation was undiminished for the 28-day testing period. Statistical analyses for (A) oxaliplatin: two-way repeated-measures ANOVA, Time × RAGE AS-ODN interaction, F(5,50) = 6.772, P < 0.0001; RAGE AS-ODN treatment, F(1,10) = 637.3, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ****P < 0.0001 (RAGE SE-ODN versus AS-ODN); (B) paclitaxel: two-way repeated-measures ANOVA, Time × RAGE AS-ODN interaction, F(7,70) = 21.52, P < 0.0001; RAGE AS-ODN treatment, F(1,10) = 151.6, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ***P = 0.0002, ****P < 0.0001, ^aaaP = 0.0006, ^cccP = 0.0004 (RAGE SE-ODN versus AS-ODN); and (C) bortezomib: two-way repeated-measures ANOVA, Time × RAGE AS-ODN interaction, F(6,60) = 19.11, P < 0.0001; RAGE AS-ODN treatment, F(1,10) = 238.3, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, **P = 0.0071, ****P < 0.0001, ***P = 0.0002, ^aaaP = 0.0007, ^cccP = 0.0006 (RAGE SE-ODN versus AS-ODN). *Bottom*: Separate groups of male rats received: (D) oxaliplatin (2 mg/kg, i.v., on Day 0); (E) paclitaxel (1 mg/kg, i.p., on Days 0, 2, 4 and 6); or (F) bortezomib (0.2 mg/kg, i.v., on Days 0, 2, 4 and 6). Each group was then treated intrathecally with an AS-ODN or SE-ODN (both 120 μg in 20 μl/day) against RAGE mRNA once a day starting 3 days after the last dose of chemotherapy drug, for seven doses, over 10 days. The mechanical nociceptive threshold was evaluated from Days 0 to 28. In the RAGE AS-ODN-treated groups, CIPN hyperalgesia was markedly attenuated in oxaliplatin-, paclitaxel- and bortezomib-treated rats, and this attenuation was undiminished for the 28-day testing period. Statistical analyses for (D) oxaliplatin: two-way repeated-measures ANOVA, Time × RAGE AS-ODN interaction, F(4,40) = 94.86, P < 0.0001; RAGE AS-ODN treatment, F(1,10) = 862.4, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ****P < 0.0001 (RAGE SE-ODN versus AS-ODN); (E) paclitaxel: two-way repeated-measures ANOVA, Time × RAGE AS-ODN interaction, F(4,40) = 91.51, P < 0.0001; RAGE AS-ODN treatment, F(1,10) = 69.15, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ****P < 0.0001 (RAGE SE-ODN versus AS-ODN); and (F) bortezomib: two-way repeated-measures ANOVA, Time × RAGE AS-ODN interaction, F(6,60) = 78.44, P < 0.0001; RAGE AS-ODN treatment, F(1,10) = 246.5, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ****P < 0.0001 (RAGE SE-ODN versus AS-ODN). n = 6 paws for each group. All data are mean ± SEM. CIPN = chemotherapy-induced peripheral neuropathy.

**Figure 7**
**TLR4 and RAGE antisense reverses oxaliplatin CIPN in female rats**. Female rats received oxaliplatin [2 mg/kg, intravenously (i.v.)] on Day 0, and 4 days later, they were treated with intrathecal antisense-oligodeoxynucleotides (AS-ODN) or mismatch (MM)/sense (SE)-ODN (both 120 μg in 20 μl/day) against (A) TLR4 or (B) RAGE mRNA, once a day for 4 days consecutively, and then three more doses, one every other day, for a total of seven doses, over 10 days. The mechanical nociceptive threshold was evaluated from Days 0 to 28. Oxaliplatin-induced hyperalgesia was markedly reversed in the (A) TLR4 and (B) RAGE AS-ODN-treated groups of female rats, and this reversal was undiminished over the 28-day testing period. Statistical analyses for A: two-way repeated-measures ANOVA, Time × TLR4 AS-ODN interaction, F(5,50) = 64.68, P < 0.0001; TLR4 AS-ODN treatment, F(1,10) = 95.41, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ****P < 0.0001 (MM-ODN versus AS-ODN); and B: two-way repeated-measures ANOVA, Time × RAGE AS-ODN interaction, F(5,50) = 77.11, P < 0.0001; RAGE AS-ODN treatment, F(1,10) = 368.2, P < 0.0001; Bonferroni's multiple *post hoc* comparisons test, ****P < 0.0001 (SE-ODN versus AS-ODN). n = 6 paws for each group. All data are mean ± SEM. CIPN = chemotherapy-induced peripheral neuropathy.

**Figure 8**
**Schematic summary of the effects of chemotherapeutic agents on pattern recognition receptors in dorsal root ganglia**. Oxaliplatin, paclitaxel and bortezomib, administered systemically, act on pattern recognition receptors (PRRs; TLR4 and RAGE), present on cells in dorsal root ganglia (DRG) to produce chemotherapy-induced peripheral neuropathy (CIPN) hyperalgesia. Once TLR4 and RAGE are knocked down, in DRG cells, chemotherapeutic drugs are not able to produce CIPN hyperalgesia. It has previously been demonstrated that immune cells infiltrate DRG after administration of chemotherapeutic drugs and release potent pro-inflammatory mediators such as tumor necrosis factor-α (TNFα), interleukin-1β (IL-1β), monocyte chemoattractant protein-1 (MCP-1), nerve growth factor (NGF), nitric oxide (NO) and prostanoids. Additionally, chemotherapeutic drugs activate microglia in the spinal dorsal horn, releasing chemokines and cytokines, which can activate astrocytes.^, Chemotherapy also alters the expression and function of ion channels in the spinal dorsal horn.^, The schematic summary was designed using BioRender.com.

See this image and copyright information in PMC

Cited by

Paclitaxel triggers molecular and cellular changes in the choroid plexus.
Zamani A, EmamiAref P, Kubíčková L, Hašanová K, Šandor O, Dubový P, Joukal M. Zamani A, et al. Front Pain Res (Lausanne). 2024 Nov 25;5:1488369. doi: 10.3389/fpain.2024.1488369. eCollection 2024. Front Pain Res (Lausanne). 2024. PMID: 39654799 Free PMC article.
TLR-4: a promising target for chemotherapy-induced peripheral neuropathy.
Babu N, Gadepalli A, Akhilesh, Sharma D, Singh AK, Chouhan D, Agrawal S, Tiwari V. Babu N, et al. Mol Biol Rep. 2024 Oct 28;51(1):1099. doi: 10.1007/s11033-024-10038-1. Mol Biol Rep. 2024. PMID: 39466456 Review.
The interplay between the microbiota and opioid in the treatment of neuropathic pain.
Gong Z, Xue Q, Luo Y, Yu B, Hua B, Liu Z. Gong Z, et al. Front Microbiol. 2024 Jun 10;15:1390046. doi: 10.3389/fmicb.2024.1390046. eCollection 2024. Front Microbiol. 2024. PMID: 38919504 Free PMC article. Review.
Mu-Opioid Receptor (MOR) Dependence of Pain in Chemotherapy-Induced Peripheral Neuropathy.
Araldi D, Staurengo-Ferrari L, Bogen O, Bonet IJM, Green PG, Levine JD. Araldi D, et al. J Neurosci. 2024 Oct 16;44(42):e0243242024. doi: 10.1523/JNEUROSCI.0243-24.2024. J Neurosci. 2024. PMID: 39256047 Free PMC article.
G-protein-coupled estrogen receptor 30 regulation of signaling downstream of protein kinase Cε mediates sex dimorphism in hyaluronan-induced antihyperalgesia.
Bonet IJM, Araldi D, Khomula EV, Bogen O, Green PG, Levine JD. Bonet IJM, et al. Pain. 2025 Mar 1;166(3):539-556. doi: 10.1097/j.pain.0000000000003419. Epub 2024 Oct 10. Pain. 2025. PMID: 39787533

See all "Cited by" articles

References

1. Maihofner C, Diel I, Tesch H, Quandel T, Baron R. Chemotherapy-induced peripheral neuropathy (CIPN): Current therapies and topical treatment option with high-concentration capsaicin. Support Care Cancer. 2021;29:4223–4238. - PMC - PubMed
1. Miaskowski C, Mastick J, Paul SM, et al. . Chemotherapy-induced neuropathy in cancer survivors. J Pain Symptom Manage. 2017;54:204–218.e2. - PMC - PubMed
1. Salat K. Chemotherapy-induced peripheral neuropathy: Part 1-current state of knowledge and perspectives for pharmacotherapy. Pharmacol Rep. 2020;72:486–507. - PMC - PubMed
1. D'Souza RS, Her YF, Jin MY, Morsi M, Abd-Elsayed A. Neuromodulation therapy for chemotherapy-induced peripheral neuropathy: A systematic review. Biomedicines. 2022;10:1909. - PMC - PubMed
1. Kolb NA, Smith AG, Singleton JR, et al. . The association of chemotherapy-induced peripheral neuropathy symptoms and the risk of falling. JAMA Neurol. 2016;73:860–866. - PMC - PubMed

Publication types

Actions

MeSH terms

Actions
Actions
Actions
Actions
Actions
Actions
Actions
Actions
Actions
Actions
Actions
Actions

Substances

Actions
Actions
Actions
Actions
Actions
Actions

Grants and funding

R01 CA250017/CA/NCI NIH HHS/United States

LinkOut - more resources

Full Text Sources
Research Materials
- NCI CPTC Antibody Characterization Program

[1] Maihofner C, Diel I, Tesch H, Quandel T, Baron R. Chemotherapy-induced peripheral neuropathy (CIPN): Current therapies and topical treatment option with high-concentration capsaicin. Support Care Cancer. 2021;29:4223–4238. - PMC - PubMed

[2] Maihofner C, Diel I, Tesch H, Quandel T, Baron R. Chemotherapy-induced peripheral neuropathy (CIPN): Current therapies and topical treatment option with high-concentration capsaicin. Support Care Cancer. 2021;29:4223–4238. - PMC - PubMed

[3] Miaskowski C, Mastick J, Paul SM, et al. . Chemotherapy-induced neuropathy in cancer survivors. J Pain Symptom Manage. 2017;54:204–218.e2. - PMC - PubMed

[4] Miaskowski C, Mastick J, Paul SM, et al. . Chemotherapy-induced neuropathy in cancer survivors. J Pain Symptom Manage. 2017;54:204–218.e2. - PMC - PubMed

[5] Salat K. Chemotherapy-induced peripheral neuropathy: Part 1-current state of knowledge and perspectives for pharmacotherapy. Pharmacol Rep. 2020;72:486–507. - PMC - PubMed

[6] Salat K. Chemotherapy-induced peripheral neuropathy: Part 1-current state of knowledge and perspectives for pharmacotherapy. Pharmacol Rep. 2020;72:486–507. - PMC - PubMed

[7] D'Souza RS, Her YF, Jin MY, Morsi M, Abd-Elsayed A. Neuromodulation therapy for chemotherapy-induced peripheral neuropathy: A systematic review. Biomedicines. 2022;10:1909. - PMC - PubMed

[8] D'Souza RS, Her YF, Jin MY, Morsi M, Abd-Elsayed A. Neuromodulation therapy for chemotherapy-induced peripheral neuropathy: A systematic review. Biomedicines. 2022;10:1909. - PMC - PubMed

[9] Kolb NA, Smith AG, Singleton JR, et al. . The association of chemotherapy-induced peripheral neuropathy symptoms and the risk of falling. JAMA Neurol. 2016;73:860–866. - PMC - PubMed

[10] Kolb NA, Smith AG, Singleton JR, et al. . The association of chemotherapy-induced peripheral neuropathy symptoms and the risk of falling. JAMA Neurol. 2016;73:860–866. - PMC - PubMed

Save citation to file

Email citation

Add to Collections

Add to My Bibliography

Your saved search

Create a file for external citation management software

Your RSS Feed

Role of pattern recognition receptors in chemotherapy-induced neuropathic pain

Affiliations

Role of pattern recognition receptors in chemotherapy-induced neuropathic pain

Authors

Affiliations

Abstract

Conflict of interest statement

Figures

Similar articles

Cited by

References

Publication types

MeSH terms

Substances

Grants and funding

LinkOut - more resources

Full Text Sources

Research Materials

Abstract

Conflict of interest statement

Figures

Similar articles

Cited by

References

Publication types

MeSH terms

Substances

Related information

Grants and funding

LinkOut - more resources

Full Text Sources

Research Materials