first you need to make some changes in the App\Exceptions\Handler

public function render($request, Exception $e)
{
    if ($e instanceof MyException) {
        return response()->json(['exception' => get_class($e), 'message' => $e->getMessage(), 'errors' => $e->getErrors()], 400);
    }

     return parent::render($request, $e);
}

Now you need your own exception class

class MyException extends RuntimeException
{

    private $errors;

    public function __construct($message, $code = 0, Exception $previous = null, $errors = []) 
    {
        parent::__construct($message, $code, $previous);

        $this->errors = $errors; 
    }

    public function getErrors() 
    { 
        return $this->errors; 
    }
}

usage

throw new MyException('exception occured', $errorCode, null, $errorsArray);