Overriding region theme file for user profile pages
I found solution on this blog http://eureka.ykyuen.info/2012/05/10/drupal-7-customize-region-template-file-for-specific-content-type/
and here is my code to suggest a user profile region.

    function YOURTHEME_alpha_preprocess_region(&amp;$vars) {
      $menu_object = menu_get_object();
      if (isset($menu_object-&gt;type) &amp;&amp; $vars['region'] == 'content') {
        $vars['theme_hook_suggestions'][] = 'region__content__'.$menu_object-&gt;type;
        $vars['attributes_array']['class'][] = 'region-content-'.$menu_object-&gt;type;
      }
//theme suggestion for user profile
      elseif ($vars['region'] == 'content' &amp;&amp; $vars['elements']["system_main"] &amp;&amp; $vars['elements']["system_main"]["#entity_type"] == 'user') {
        $vars['theme_hook_suggestions'][] = 'region__content__userprofile';
        $vars['attributes_array']['class'][] = 'region-content-userprofile';
      }
    }