Surfactant protein A is expressed in the central nervous system of rats with experimental autoimmune encephalomyelitis, and suppresses inflammation in human astrocytes and microglia

Abstract

The collectin surfactant protein-A (SP-A), a potent host defense molecule, is well recognized for its role in the maintenance of pulmonary homeostasis and the modulation of inflammatory responses. While previous studies have detected SP-A in numerous extrapulmonary tissues, there is still a lack of information regarding its expression in central nervous system (CNS) and potential effects in neuroinflammatory diseases, such as multiple sclerosis (MS). The present study used experimental autoimmune encephalomyelitis (EAE), the most commonly used animal model of MS, to investigate the expression of SP-A in the CNS at different stages of disease progression. In addition, in vitro experiments with lipopolysaccharide (LPS)-stimulated human astrocytes and microglia were performed to investigate the potential role of SP-A in the modulation of CNS inflammatory responses. The results of the present study demonstrated widespread distribution of SP-A in the rat CNS, and also identified specific expression patterns of SP-A at different stages of EAE. In vitro, the current study revealed that treatment of human astrocytes and microglia with LPS promoted SP-A expression in a dose-dependent manner. Furthermore, exogenous SP-A protein significantly decreased Toll-like receptor 4 and nuclear factor-κB expression, and reduced interleukin-1β and tumor necrosis factor-α levels. The results of the current study indicate a potential role for SP-A in the modulation of CNS inflammatory responses.

Extra-Virgin Olive Oil Modifies the Changes Induced in Non-Nervous Organs and Tissues by Experimental Autoimmune Encephalomyelitis Models

“…Different expression patterns have recently been revealed in the rat CNS of the collectin surfactant protein-A (SP-A) in inflammatory response modulation in EAE. Also, in vitro treatment of human astrocytes and microglia with LPS promoted SP-A expression in a dose-dependent manner [41]. In fact, its levels were lower in the cerebrospinal fluid of patients with MS [42,43].…”

“…In fact, its levels were lower in the cerebrospinal fluid of patients with MS [42,43]. SP-A significantly decreases Toll-like receptor 4 and nuclear factor-κB expression, and reduces interleukin-1β and tumor necrosis factor-α levels [41].…”

“…The protein SP-A is not only present in the CNS but also in extra-nervous tissues. Thus, it has been localized in the lung, where it plays a basic role in pulmonary homeostasis and inflammatory response, and also in several extrapulmonary tissues among which the intestine, colon, and mucosa are included [41,44,45]. That discovery led us to develop the idea that the inflammation and oxidative stress accompanying MS and EAE could also be present in other extra-nervous tissues where the protein SP-A could express itself.…”

CSF Surfactant Protein Changes in Preterm Infants After Intraventricular Hemorrhage

“…SP-C levels were reduced within the follow-up period to levels of hydrocephalus patients without hemorrhagic origin. As postulated previously, SP-C may be elevated downstream due to mechanical stress and consecutive increase of intracranial pressure ( 3 – 5 ). Of note, two patients with low SP-C concentrations at 5–10 days after primary intervention did not require shunt surgery.…”

“…In parallel the opsonins SP-A and SP-D are found at the sites of the blood-brain and the blood-CSF barrier, respectively (3). Furthermore, the SPs are also present in significant concentrations in cerebrospinal fluid (CSF) (2,4,5).…”