Browsing by Subject "mesencephalic astrocyte- derived neurotrophic factor (MANF)"

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by selective loss of upper and lower motor neurons (MN), which causes progressive muscle weakness and paralysis. ALS leads to death typically from 2 to 4 years after diagnosis. It is important to find more effective treatment options for this devastating disease, as the current treatments can prolong the survival by only a few months. Mesencephalic astrocyte-derived neurotrophic factor (MANF) belongs to an evolutionary conserved neurotrophic factor (NTF) family, whose mode of action differs from classical NTFs. MANF is an endoplasmic reticulum (ER) resident protein and is secreted upon ER stress from the ER, and it can protect the cells from ER stress-induced cell death. MANF has shown to be neuroprotective and –restorative in Parkinson’s disease and stroke rodent models. Adeno-associated viral (AAV) vectors can be used to express therapeutic genes in the target tissues for several months, which lessens the need for repetitive dosing. In this master’s thesis project, we aimed to investigate the neuroprotective effects of intrathecally injected AAV1-MANF gene therapy in a SOD1-G93A mouse model of ALS. We used two different MANF genes; full-length MANF and MANF with deleted ER retention signal (MANF-d), to assess the differences between normal and only secreted MANF. Red fluorescent protein (RFP) was used as a control and to further evaluate the transduction and expression of the viral vectors. Intrathecal injections were performed once on 13 weeks old mice, just before the disease onset. Clinical symptom analyses together with a set of behavioral tests were conducted once a week. Mice were sacrificed at the endpoint of the study when they could no longer use their hind limbs for forwarding propulsion. Immunohistochemical staining was performed on spinal cord paraffin samples, where MN count, microglia activation, and RFP expression were evaluated. AAV1-MANF and AAV1-MANF-d treatments improved the motor behavior of the SOD1-G93A mice one-week post- injection. More specifically, a statistically significant difference was seen in the turning times in the static rods test on two different diameter rods compared to control, but there was no difference between MANF groups. In addition, there was a notable difference between AAV1-MANF and the control group on week 16 rotarod scores. There were no statistically significant differences in other tests, survival of the mice, MN counts, or microglia activation between the groups. RFP expression was detected mainly in the ventral areas of the spinal cord with immunohistochemistry. Our results indicate the potential of MANF gene therapy in the treatment of ALS. Furthermore, we showed that intrathecal AAV1-MANF injections were well tolerated.