Detection of endoplasmic reticulum stress and the unfolded protein response in naturally-occurring endocrinopathic equine laminitis
Abstract Background Laminitis is often associated with endocrinopathies that cause hyperinsulinemia and is also induced experimentally by hyperinsulinemia, suggesting that insulin initiates laminitis pathogenesis. Hyperinsulinemia is expected to activate pro-growth and anabolic signaling pathways. W...
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| Format: | Article |
| Language: | English |
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BMC
2019-01-01
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| Series: | BMC Veterinary Research |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s12917-018-1748-x |
| _version_ | 1818521745139695616 |
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| author | Lynne Cassimeris Julie B. Engiles Hannah Galantino-Homer |
| author_facet | Lynne Cassimeris Julie B. Engiles Hannah Galantino-Homer |
| author_sort | Lynne Cassimeris |
| collection | DOAJ |
| description | Abstract Background Laminitis is often associated with endocrinopathies that cause hyperinsulinemia and is also induced experimentally by hyperinsulinemia, suggesting that insulin initiates laminitis pathogenesis. Hyperinsulinemia is expected to activate pro-growth and anabolic signaling pathways. We hypothesize that chronic over-stimulation of these pathways in lamellar tissue results in endoplasmic reticulum stress, contributing to tissue pathology, as it does in human metabolic diseases. We tested this hypothesis by asking whether lamellar tissue from horses with naturally-occurring endocrinopathic laminitis showed expression of protein markers of endoplasmic reticulum stress. Results Three markers of endoplasmic reticulum stress, spliced XBP1, Grp78/BiP and Grp94, were upregulated 2.5–9.5 fold in lamellar tissues of moderately to severely laminitic front limbs (n = 12) compared to levels in controls (n = 6–7) measured by immunoblotting and densitometry. Comparing expression levels between laminitic front limbs and less affected hind limbs from the same horses (paired samples from 7 to 8 individual horses) demonstrated significantly higher expression for both spliced XBP1 and Grp78/BiP in the laminitic front limbs, and a similar trend for Grp94. Expression levels of the 3 markers were minimal in all samples of the control (n = 6–7) or hind limb groups (n = 7–8). Immunofluorescent localizations were used to identify cell types expressing high levels of Grp78/BiP, as an indicator of endoplasmic reticulum stress. Grp78/BiP expression was highly elevated in suprabasal epidermal keratinocytes and only observed in laminitic front limbs (10/12 laminitic samples, compared to 0/7 in sections from the hind limbs and 0/5 of controls). Conclusions These data demonstrate that the endoplasmic reticulum stress pathway is active in naturally occurring cases of laminitis and is most active within a subset of epidermal keratinocytes. These data provide the rationale for further study of endoplasmic reticulum stress in experimental models of laminitis and the links between laminitis and human diseases sharing activation of this stress pathway. Pharmacological options to manipulate the endoplasmic reticulum stress pathway under investigation for human disease could be applicable to laminitis treatment and prevention should this pathway prove to be a driver of disease progression. |
| first_indexed | 2024-12-11T01:55:29Z |
| format | Article |
| id | doaj.art-384b451274534f3ebd611b05eb5e785c |
| institution | Directory Open Access Journal |
| issn | 1746-6148 |
| language | English |
| last_indexed | 2024-12-11T01:55:29Z |
| publishDate | 2019-01-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Veterinary Research |
| spelling | doaj.art-384b451274534f3ebd611b05eb5e785c2022-12-22T01:24:38ZengBMCBMC Veterinary Research1746-61482019-01-0115111610.1186/s12917-018-1748-xDetection of endoplasmic reticulum stress and the unfolded protein response in naturally-occurring endocrinopathic equine laminitisLynne Cassimeris0Julie B. Engiles1Hannah Galantino-Homer2Department of Biological Sciences, Lehigh UniversityDepartment of Clinical Studies/New Bolton Center, School of Veterinary Medicine, University of PennsylvaniaDepartment of Clinical Studies/New Bolton Center, School of Veterinary Medicine, University of PennsylvaniaAbstract Background Laminitis is often associated with endocrinopathies that cause hyperinsulinemia and is also induced experimentally by hyperinsulinemia, suggesting that insulin initiates laminitis pathogenesis. Hyperinsulinemia is expected to activate pro-growth and anabolic signaling pathways. We hypothesize that chronic over-stimulation of these pathways in lamellar tissue results in endoplasmic reticulum stress, contributing to tissue pathology, as it does in human metabolic diseases. We tested this hypothesis by asking whether lamellar tissue from horses with naturally-occurring endocrinopathic laminitis showed expression of protein markers of endoplasmic reticulum stress. Results Three markers of endoplasmic reticulum stress, spliced XBP1, Grp78/BiP and Grp94, were upregulated 2.5–9.5 fold in lamellar tissues of moderately to severely laminitic front limbs (n = 12) compared to levels in controls (n = 6–7) measured by immunoblotting and densitometry. Comparing expression levels between laminitic front limbs and less affected hind limbs from the same horses (paired samples from 7 to 8 individual horses) demonstrated significantly higher expression for both spliced XBP1 and Grp78/BiP in the laminitic front limbs, and a similar trend for Grp94. Expression levels of the 3 markers were minimal in all samples of the control (n = 6–7) or hind limb groups (n = 7–8). Immunofluorescent localizations were used to identify cell types expressing high levels of Grp78/BiP, as an indicator of endoplasmic reticulum stress. Grp78/BiP expression was highly elevated in suprabasal epidermal keratinocytes and only observed in laminitic front limbs (10/12 laminitic samples, compared to 0/7 in sections from the hind limbs and 0/5 of controls). Conclusions These data demonstrate that the endoplasmic reticulum stress pathway is active in naturally occurring cases of laminitis and is most active within a subset of epidermal keratinocytes. These data provide the rationale for further study of endoplasmic reticulum stress in experimental models of laminitis and the links between laminitis and human diseases sharing activation of this stress pathway. Pharmacological options to manipulate the endoplasmic reticulum stress pathway under investigation for human disease could be applicable to laminitis treatment and prevention should this pathway prove to be a driver of disease progression.http://link.springer.com/article/10.1186/s12917-018-1748-xHorseLamellaHoofInsulinCell stress |
| spellingShingle | Lynne Cassimeris Julie B. Engiles Hannah Galantino-Homer Detection of endoplasmic reticulum stress and the unfolded protein response in naturally-occurring endocrinopathic equine laminitis BMC Veterinary Research Horse Lamella Hoof Insulin Cell stress |
| title | Detection of endoplasmic reticulum stress and the unfolded protein response in naturally-occurring endocrinopathic equine laminitis |
| title_full | Detection of endoplasmic reticulum stress and the unfolded protein response in naturally-occurring endocrinopathic equine laminitis |
| title_fullStr | Detection of endoplasmic reticulum stress and the unfolded protein response in naturally-occurring endocrinopathic equine laminitis |
| title_full_unstemmed | Detection of endoplasmic reticulum stress and the unfolded protein response in naturally-occurring endocrinopathic equine laminitis |
| title_short | Detection of endoplasmic reticulum stress and the unfolded protein response in naturally-occurring endocrinopathic equine laminitis |
| title_sort | detection of endoplasmic reticulum stress and the unfolded protein response in naturally occurring endocrinopathic equine laminitis |
| topic | Horse Lamella Hoof Insulin Cell stress |
| url | http://link.springer.com/article/10.1186/s12917-018-1748-x |
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