Myosin heavy chain gene expression in normal and hyperplastic human prostate tissue.

Area of Science:

• Urology
• Molecular Pathophysiology
• Cell Biology

Background:

• Benign prostatic hyperplasia (BPH) is a prevalent condition in aging men, causing bladder outlet obstruction.
• The molecular mechanisms underlying BPH, particularly alterations in prostatic smooth muscle (SM), remain poorly understood.
• Current research explores hormonal effects, cell interactions, and growth factors, but SM changes are understudied.

Purpose of the Study:

• To investigate smooth muscle (SM) phenotypic modulation in hyperplastic prostatic growth.
• To analyze the expression of smooth muscle myosin heavy chain (SMMHC) and nonmuscle myosin heavy chain (NMMHC) in normal and hyperplastic prostate tissues.
• To determine if BPH tissue exhibits altered SMMHC and NMMHC expression compared to normal prostate.

Main Methods:

• Isolated and characterized the 3' end of human SM myosin heavy chain (SMMHC) cDNA.
• Utilized Western blot, Northern blot, and in situ hybridization to assess SMMHC and NMMHC expression.
• Employed competitive reverse transcription polymerase chain reaction (RT-PCR) to quantify SMMHC and NMMHC mRNA levels.

Main Results:

• Both SMMHC and NMMHC are expressed in the human prostate; SMMHC is predominant in normal stroma.
• SMMHC mRNA expression was significantly reduced (nearly fivefold) in BPH tissue compared to normal prostate.
• No significant difference in NMMHC mRNA expression was observed between normal and BPH tissues.

Conclusions:

• BPH pathogenesis involves a unique SM proliferation characterized by downregulated SMMHC mRNA without NMMHC upregulation.
• This pattern mirrors proliferating SM cells in culture and other pathological SM hyperplasias.
• Therapeutic strategies targeting early BPH growth phases are recommended to prevent disease progression.