Abundant FUS-immunoreactive pathology in the skin of sporadic amyotrophic lateral sclerosis

OBJECTIVES

The fused in sarcoma (FUS) protein is a 526 amino acid and its expression is ubiquitous. Recently, mutations in a gene coding FUS have been identified in familial amyotrophic lateral sclerosis (ALS). Also, FUS has been found in neuronal cytoplasmic inclusions in sporadic forms of ALS, suggesting that FUS has an important role in the neurodegeneration occurring in sporadic disease. However, there has been no study of FUS in ALS skin.

MATERIAL AND METHODS

We made a quantitative immunohistochemical study of the expression of FUS in the skin from patients with sporadic ALS and controls.

RESULTS

The proportion of FUS-immunoreactive (ir) cells in the epidermis in ALS patients was significantly higher (P < 0.001) than in controls. There was a significant positive relationship (r = 0.78, P < 0.001) between the proportion and duration of illness in ALS patients. The optical density of FUS-ir cells in the epidermis in ALS patients is markedly stronger (P < 0.001) than in controls. There was a significant positive relation (r = 0.49, P < 0.05) between the immunoreactivity and duration of illness in ALS patients.

CONCLUSIONS

These data suggest that changes of FUS in ALS skin are related to the disease process, and that metabolic alterations of FUS may take place in the skin of patients with ALS.

Expression of hepatocyte growth factor in the skin of amyotrophic lateral sclerosis

OBJECTIVES

Hepatocyte growth factor (HGF) is one of the most potent survival-promoting factors for motor neurons. Overexpression of neuronal HGF has been shown to result in the attenuation of neuronal cell death and progression of disease in a familial amyotrophic lateral sclerosis (ALS) transgenic mouse model. HGF might be beneficial for motor neuron survival and is a good candidate agent for the treatment of ALS. So far, studies of the skin of ALS have shown unique pathological and biochemical abnormalities. However, there has been no study of HGF in ALS skin.

MATERIALS AND METHODS

We made a quantitative immunohistochemical study of the expression of HGF in the skin from 19 patients with sporadic ALS and 16 controls.

RESULTS

Hepatocyte growth factor immunoreactivity was positive in the epidermis, some dermal blood vessels, and glands in patients with ALS. These findings became more conspicuous as ALS progressed. The optical density for HGF immunoreactivity of the nucleus and the cytoplasm in the epidermis in ALS was significantly higher (P < 0.001 and P < 0.001) than in controls. There was a significant positive relation (r = 0.53, P < 0.02 and r = 0.73, P < 0.001) between HGF immunoreactivity and duration of illness in the nucleus and the cytoplasm in the epidermis in patients with ALS.

CONCLUSIONS

These findings suggest that changes in HGF in ALS skin are related to the disease process and that metabolic alterations of HGF may take place in the skin of patients with ALS.

Increased progranulin in the skin of amyotrophic lateral sclerosis: an immunohistochemical study

It has been demonstrated that progranulin (PGRN) is a neurotrophic factor that enhances neuronal survival and axonal growth. Several lines of evidence have indicated that PGRN plays a role in the pathomechanism of amyotrophic lateral sclerosis (ALS). However, there has no study of PGRN in ALS skin. We made a quantitative immunohistochemical study of the expression of PGRN in the skin from 18 patients with sporadic ALS and 13 control subjects. Immunohistochemistry for PGRN demonstrated cytoplasmic activity in the epidermis and in some blood vessels and glands. Numerous PGRN-positive (PGRN+) cells were observed in the epidermis in ALS patients, which became more marked as ALS progressed. PGRN immunoreactivity of PGRN+cells was markedly positive in the epidermis in ALS patients. The proportion of PGRN+cells in the epidermis in ALS patients was significantly higher (p<0.001) than in controls. There was a significant positive relationship (r = 0.83, p<0.001) between the proportion and duration of illness in ALS patients. These data suggest that changes of PGRN in ALS skin are related to the disease process and that metabolic alteration of PGRN may take place in the skin of patients with ALS.