Sickle cell disease is accompanied by both chronic and severe episodic pain that is difficult to treat, and profoundly erodes the quality of life of those who suffer from it. Despite a detailed understanding of the genetics, molecular biology and biochemistry of sickle hemoglobin, the pathogenesis of the profound pain syndromes observed in sickle cell disease remain incompletely understood and likely involve complex and heterogeneous steps occurring in both the peripheral and central nervous systems. The goal of this proposal is to elucidate the mechanisms by which sickle cell disease results in pain, focusing on peripheral mechanisms in primary afferent nerve terminals. Using a murine model of severe sickle cell disease, the Berkeley Sickle Mice, we demonstrate that these mice exhibit marked hypersensitivity to mechanical, heat and cold peripheral stimuli. Furthermore, induction of acute sickling with hypoxia specifically exacerbates the ongoing mechanical hypersensitivity in sickle cell mice. In agreement, teased fiber recordings from skin-nerve preparations from these mice indicate that both myelinated A? fiber and unmyelinated C fiber nociceptors are sensitized to mechanical stimuli. These findings parallel the mechanical hypersensitivity and pain reported by patients with sickle cell disease. Thus, these sickle cell mice represent a novel model of long-lasting chronic pain hypersensitivity that is closely associated with a human disease. On the basis of these findings and our observations with sensory plasticity in other pain models, we hypothesize that sensitization of primary afferent terminals contributes to sickle cell pain and that this sensitization is mediated by increased function of Transient Receptor Potential ion channels. Therefore, the Specific Aims for this project are to 1) Characterize the sensitization state of primary afferent fibers to mechanical, heat and cold stimuli in mice with sickle cell disease. 2) Determine the contribution of the Transient Receptor Potential (TRP) Ion Channels TRPA1 and TRPV1 to both the behavioral hypersensitivity and the sensitization of primary afferent fibers in sickle cell disease. 3) Characterize how acute vaso-occlusion modulates mechanical hypersensitivity in sickle mice. We will use both ex vivo and in vivo electrophysiological recordings to characterize the sensitization state of primary afferent fibers in Berkeley sickle cell mice. Next, we will utilize both genetic (TRP channel null mice induced with sickle cell disease) and pharmacologic approaches (selective TRP channel antagonists) to determine the role of specific TRP-family ion channels in sickle cell-associated primary afferent sensitization and pain behavior. Finally, we will induce acute sickling crises by an experimental model of vaso-occlusion to study how vaso-occlusion modulates mechanical hypersensitivity in sickle mice. These interrelated Specific Aims provide a multifaceted, coordinated and tightly focused approach that will clarify the role of primary afferent neurons in the development of pain syndromes within the complex setting of sickle cell-induced vascular and organ pathologies, as well as provide insight into the potential value of targeted TRP antagonist therapies for sickle cell pain.

Public Health Relevance

Sickle cell disease is an inherited disorder of the red blood cell wherein an abnormal hemoglobin molecule (called sickle hemoglobin) can cause the red cell to change shape and clog blood vessels resulting in severe pain and suffering. In 2003 alone, there were over 20,000 hospitalizations for children with sickle cell disease and over 16,000 of these were for vaso- occlusive painful events resulting in over 65,000 hospital days per year. The pain and disability are even more severe in adults. In this grant, we intend to study the precise nerve cells and pathways that sense the pain and carry the message to the brain so that we can develop new methods to treat sickle cell disease more safely and effectively.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZHL1-CSR-Y (S1))
Program Officer
Porter, Linda L
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Medical College of Wisconsin
Anatomy/Cell Biology
Schools of Medicine
United States
Zip Code
Zappia, Katherine J; Guo, Yihe; Retherford, Dawn et al. (2017) Characterization of a mouse model of sickle cell trait: parallels to human trait and a novel finding of cutaneous sensitization. Br J Haematol 179:657-666
Brandow, Amanda M; Zappia, Katherine J; Stucky, Cheryl L (2017) Sickle cell disease: a natural model of acute and chronic pain. Pain 158 Suppl 1:S79-S84
Zappia, Katherine J; Garrison, Sheldon R; Palygin, Oleg et al. (2016) Mechanosensory and ATP Release Deficits following Keratin14-Cre-Mediated TRPA1 Deletion Despite Absence of TRPA1 in Murine Keratinocytes. PLoS One 11:e0151602
Moehring, Francie; O'Hara, Crystal L; Stucky, Cheryl L (2016) Bedding Material Affects Mechanical Thresholds, Heat Thresholds, and Texture Preference. J Pain 17:50-64
Lehto, Sonya G; Weyer, Andy D; Youngblood, Beth D et al. (2016) Selective antagonism of TRPA1 produces limited efficacy in models of inflammatory- and neuropathic-induced mechanical hypersensitivity in rats. Mol Pain 12:
Weyer, Andy D; Zappia, Katherine J; Garrison, Sheldon R et al. (2016) Nociceptor Sensitization Depends on Age and Pain Chronicity(1,2,3). eNeuro 3:
Osteen, Jeremiah D; Herzig, Volker; Gilchrist, John et al. (2016) Selective spider toxins reveal a role for the Nav1.1 channel in mechanical pain. Nature 534:494-9
Weyer, Andy D; O'Hara, Crystal L; Stucky, Cheryl L (2015) Amplified Mechanically Gated Currents in Distinct Subsets of Myelinated Sensory Neurons following In Vivo Inflammation of Skin and Muscle. J Neurosci 35:9456-62
Morita, Takeshi; McClain, Shannan P; Batia, Lyn M et al. (2015) HTR7 Mediates Serotonergic Acute and Chronic Itch. Neuron 87:124-38
Wandersee, Nancy J; Maciaszek, Jamie L; Giger, Katie M et al. (2015) Dietary supplementation with docosahexanoic acid (DHA) increases red blood cell membrane flexibility in mice with sickle cell disease. Blood Cells Mol Dis 54:183-8

Showing the most recent 10 out of 35 publications