Neurosteroidogenesis and progesterone anti-inflammatory/neuroprotective effects.

Progesterone shows anti-inflammatory and promyelinating effects in mice with experimental autoimmune encephalomyelitis (EAE), a commonly used model for multiple sclerosis (MS). Because neurosteroids have been implicated as protective factors for MS and EAE, we analysed the expression of neurosteroidogenic enzymes in the compromised spinal cord of EAE mice. EAE was induced in female C57Bl6 mice, which were then killed on day 16 after induction. Progesterone was given by pellet implantation 1 week before EAE induction. Untreated EAE mice showed decreased mRNAs for the steroidogenic acute regulatory protein (Star), voltage-dependent anion channel (VDAC), cholesterol side-chain cleavage (P450scc), 5α-reductase, 3α-hydroxysteroid dehydrogenase (3α-HSOR) and aromatase, whereas changes of 3ß-hydroxysteroid dehydrogenase (3ß-HSD) were not significant. mRNA translocator protein (18 kDa) (TSPO) was elevated, concomitantly with a reactive microgliosis. EAE mice also showed abnormal mitochondrial ultrastructure in axons and neuronal bodies, as well as reduced expression of fission and fusion protein mRNAs. Progesterone pretreatment before EAE induction increased Star, VDAC, P450scc, 5α-reductase type I, 3α-HSOR and aromatase mRNAs and did not modify 3ß-HSD. TSPO mRNA was decreased, possibly as a result of reversal of microgliosis. Progesterone pretreatment also improved mitochondrial ultrastructure and increased fission/fusion protein mRNAs. These mitochondrial effects may be part of the progesterone recovery of neurosteroidogenesis. The enzymes 3ß-HSD, 3α-HSOR and 5α-reductase are also responsible for the formation of androgens. Because MS patients and EAE rodents show changes of central androgen levels, it is likely that, together with progestins and oestrogens, neuroandrogens afford neuroprotection for EAE and MS. The data reviewed suggest that enhanced synthesis of neurosteroids contributes in an auto/paracrine manner to reinforce the neuroprotective and anti-inflammatory effects of exogenous progesterone given to EAE mice.

Progesterone down-regulates spinal cord inflammatory mediators and increases myelination in experimental autoimmune encephalomyelitis.

In mice with experimental autoimmune encephalomyelitis (EAE) pretreatment with progesterone improves clinical signs and decreases the loss of myelin basic protein (MBP) and proteolipid protein (PLP) measured by immunohistochemistry and in situ hybridization. Presently, we analyzed if progesterone effects in the spinal cord of EAE mice involved the decreased transcription of local inflammatory mediators and the increased transcription of myelin proteins and myelin transcription factors. C57Bl/6 female mice were divided into controls, EAE and EAE receiving progesterone (100mg implant) 7 days before EAE induction. Tissues were collected on day 17 post-immunization. Real time PCR technology demonstrated that progesterone blocked the EAE-induced increase of the proinflammatory mediators tumor necrosis factor alpha (TNFα) and its receptor TNFR1, the microglial marker CD11b and toll-like receptor 4 (TLR4) mRNAs, and increased mRNA expression of PLP and MBP, the myelin transcription factors NKx2.2 and Olig1 and enhanced CC1+oligodendrocyte density respect of untreated EAE mice. Immunocytochemistry demonstrated decreased Iba1+microglial cells. Confocal microscopy demonstrated that TNFα colocalized with glial-fibrillary acidic protein+astrocytes and OX-42+microglial cells. Therefore, progesterone treatment improved the clinical signs of EAE, decreased inflammatory glial reactivity and increased myelination. Data suggest that progesterone neuroprotection involves the modulation of transcriptional events in the spinal cord of EAE mice.

Progesterone effects on neuronal brain-derived neurotrophic factor and glial cells during progression of Wobbler mouse neurodegeneration.

Previous results have shown a depletion of brain-derived neurotrophic factor (BDNF) mRNA in the degenerating motoneurons from clinically afflicted Wobbler mice, whereas progesterone treatment reverts this depletion. We now compared progesterone regulation of BDNF in motoneurons and oligodendrocytes of Wobbler mice at the progressive (EP, 1-3 months), symptomatic (SYM, 5-8 months old), and late stages (LS, 12-13 months). As controls we used NFR/NFR mice. Controls and Wobbler mice of different ages remained untreated or received a 20 mg progesterone pellet during 18 days. BDNF mRNA was determined in the ventral, intermediolateral, and dorsal gray matter by film autoradiography and in motoneurons using in situ hybridization. A depletion of BDNF mRNA already occurred at the EP stage of Wobblers, but progesterone was inactive at this period. In contrast, progesterone upregulated the low levels of BDNF mRNA in SYM Wobblers in the three gray matter regions analyzed. Progesterone also increased BDNF mRNA in LS Wobblers, according to grain counting procedures. BDNF protein analyzed by enzyme-linked immunosorbent assay (ELISA) in ventral horns or immunostaining of motoneurons was normal in steroid-naive SYM Wobblers. BDNF protein was decreased by progesterone, suggesting increased anterograde transport and/or release of neuronal BDNF. Wobbler mice also showed depletion of CC1-immunopositive oligodendrocytes, whereas progesterone treatment enhanced the density of BDNF+ and CC1+ oligodendrocytes in EP, SYM, and LS Wobblers. Our results suggest that BDNF could be involved in progesterone effects on motoneurons at the SYM and LS periods, whereas effects on oligodendrocytes occurred at all stages of the Wobbler disease. These steroid actions may be important to arrest the ongoing neurodegeneration.

Endogenous progesterone is associated to amyotrophic lateral sclerosis prognostic factors.

UNLABELLED: Negative prognostic factors in amyotrophic lateral sclerosis include advanced age, shorter time from disease onset to diagnosis, bulbar onset and rapid progression rate. OBJECTIVE: To compare progesterone (PROG) and cortisol serum levels in patients and controls and ascertain its relationship to prognostic factors and survival. METHODS: We assessed serum hormonal levels in 27 patients and 21 controls. RESULTS: Both hormones were 1.4-fold higher in patients. PROG showed a negative correlation with age, positive correlation with survival and positive trend with time to diagnosis. Increased PROG was observed in spinal onset and slow progression patients. No correlation was demonstrated with cortisol. CONCLUSION: Increased hormonal levels in patients are probably due to hypothalamic-pituitary-adrenal axis activation. Nevertheless, in this preliminary report only PROG correlated positively with factors predicting better prognosis and survival. We hypothesize endogenous PROG and cortisol may be engaged in differential roles, the former possibly involved in a neuroprotective response.